rusty_emu/tests/intel_400x_tests.rs

use rusty_emu::component::{BaseComponent, Component};
use rusty_emu::components::common::intel_400x::*;
use rusty_emu::components::memory::intel_4001::{Intel4001, IoDirection, IoMode};
use rusty_emu::pin::{Pin, PinValue};
use std::collections::HashMap;
use std::sync::{Arc, Mutex};
use std::time::Instant;

// Mock component for testing trait implementations
#[derive(Debug)]
struct MockComponent {}

impl MockComponent {
    fn new() -> Self {
        Self {}
    }
}

impl Component for MockComponent {
    fn name(&self) -> String {
        "MockComponent".to_string()
    }

    fn pins(&self) -> HashMap<String, Arc<Mutex<rusty_emu::pin::Pin>>> {
        HashMap::new()
    }

    fn get_pin(&self, name: &str) -> Result<Arc<Mutex<rusty_emu::pin::Pin>>, String> {
        // For testing, we'll return an error since we don't have real pins
        Err(format!("Mock pin not implemented for {}", name))
    }

    fn update(&mut self) {
        // No-op for mock
    }

    fn run(&mut self) {
        // No-op for mock
    }

    fn stop(&mut self) {
        // No-op for mock
    }

    fn is_running(&self) -> bool {
        false
    }
}

impl Intel400xAddressHandling for MockComponent {
    fn get_base(&self) -> &BaseComponent {
        unimplemented!("MockComponent doesn't contain BaseComponent")
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use std::thread;
    use std::time::Duration;

    #[test]
    fn test_timing_constants() {
        // Test that timing constants have expected values
        assert_eq!(
            TimingConstants::DEFAULT_ACCESS_TIME,
            Duration::from_nanos(500)
        );
        assert_eq!(TimingConstants::FAST_ACCESS_TIME, Duration::from_nanos(200));
        assert_eq!(TimingConstants::ADDRESS_SETUP, Duration::from_nanos(100));
        assert_eq!(TimingConstants::DATA_VALID, Duration::from_nanos(200));
    }

    #[test]
    fn test_assemble_full_address() {
        // Create a mock trait implementation for testing
        struct TestAddressHandler {}

        impl TestAddressHandler {
            fn new() -> Self {
                Self {}
            }
        }

        impl Intel400xAddressHandling for TestAddressHandler {
            fn get_base(&self) -> &BaseComponent {
                unimplemented!("TestAddressHandler doesn't contain BaseComponent")
            }
        }

        let handler = TestAddressHandler::new();

        // Test address assembly with valid nibbles
        assert_eq!(
            handler.assemble_full_address(Some(0x0F), Some(0x03)),
            Some(0xF3)
        );
        assert_eq!(
            handler.assemble_full_address(Some(0x02), Some(0x04)),
            Some(0x24)
        );
        assert_eq!(
            handler.assemble_full_address(Some(0x00), Some(0x00)),
            Some(0x00)
        );
        assert_eq!(
            handler.assemble_full_address(Some(0x0F), Some(0x0F)),
            Some(0xFF)
        );

        // Test with missing nibbles
        assert_eq!(handler.assemble_full_address(None, Some(0x23)), None);
        assert_eq!(handler.assemble_full_address(Some(0x0F), None), None);
        assert_eq!(handler.assemble_full_address(None, None), None);
    }

    #[test]
    fn test_timing_state_machine() {
        // Test state machine properties
        let idle_state = TimingState::Idle;
        let address_state = TimingState::AddressPhase;
        let wait_state = TimingState::WaitLatency;
        let drive_state = TimingState::DriveData;

        // Test state queries
        assert!(idle_state.is_idle());
        assert!(!idle_state.is_address_phase());
        assert!(!idle_state.is_waiting_latency());
        assert!(!idle_state.is_driving_data());

        assert!(!address_state.is_idle());
        assert!(address_state.is_address_phase());
        assert!(!address_state.is_waiting_latency());
        assert!(!address_state.is_driving_data());

        assert!(!wait_state.is_idle());
        assert!(!wait_state.is_address_phase());
        assert!(wait_state.is_waiting_latency());
        assert!(!wait_state.is_driving_data());

        assert!(!drive_state.is_idle());
        assert!(!drive_state.is_address_phase());
        assert!(!drive_state.is_waiting_latency());
        assert!(drive_state.is_driving_data());
    }

    #[test]
    fn test_memory_state_conversions() {
        // Test conversions between MemoryState and TimingState
        let mem_idle = MemoryState::Idle;
        let timing_idle: TimingState = mem_idle.into();
        assert_eq!(timing_idle, TimingState::Idle);

        let mem_address = MemoryState::AddressPhase;
        let timing_address: TimingState = mem_address.into();
        assert_eq!(timing_address, TimingState::AddressPhase);

        let mem_wait = MemoryState::WaitLatency;
        let timing_wait: TimingState = mem_wait.into();
        assert_eq!(timing_wait, TimingState::WaitLatency);

        let mem_drive = MemoryState::DriveData;
        let timing_drive: TimingState = mem_drive.into();
        assert_eq!(timing_drive, TimingState::DriveData);

        // Test reverse conversions
        let back_to_mem: MemoryState = timing_idle.into();
        assert_eq!(back_to_mem, MemoryState::Idle);
    }

    #[test]
    fn test_ram_state_conversions() {
        // Test conversions between RamState and TimingState
        let ram_idle = RamState::Idle;
        let timing_idle: TimingState = ram_idle.into();
        assert_eq!(timing_idle, TimingState::Idle);

        let ram_read = RamState::ReadData;
        let timing_drive: TimingState = ram_read.into();
        assert_eq!(timing_drive, TimingState::DriveData);

        let ram_write = RamState::WriteData;
        let timing_drive: TimingState = ram_write.into();
        assert_eq!(timing_drive, TimingState::DriveData);

        let ram_output = RamState::OutputPort;
        let timing_drive: TimingState = ram_output.into();
        assert_eq!(timing_drive, TimingState::DriveData);
    }

    #[test]
    fn test_utils_create_driver_name() {
        assert_eq!(create_driver_name("COMP1", "DATA"), "COMP1_DATA");
        assert_eq!(create_driver_name("MEMORY", "ADDR"), "MEMORY_ADDR");
        assert_eq!(create_driver_name("CPU", "CONTROL"), "CPU_CONTROL");
    }

    #[test]
    fn test_data_bus_bit_operations() {
        // Test bit manipulation for data bus operations
        let test_values = vec![
            (0x00, [false, false, false, false]),
            (0x01, [true, false, false, false]),
            (0x02, [false, true, false, false]),
            (0x04, [false, false, true, false]),
            (0x08, [false, false, false, true]),
            (0x05, [true, false, true, false]),
            (0x0A, [false, true, false, true]),
            (0x0F, [true, true, true, true]),
        ];

        for (value, expected_bits) in test_values {
            // Test bit extraction (reading from bus)
            for i in 0..4 {
                let bit_value = (value >> i) & 1;
                assert_eq!(bit_value == 1, expected_bits[i as usize]);
            }

            // Test bit setting (writing to bus)
            let mut reconstructed = 0;
            for i in 0..4 {
                if expected_bits[i as usize] {
                    reconstructed |= 1 << i;
                }
            }
            assert_eq!(value, reconstructed);
        }
    }

    #[test]
    fn test_address_latching_logic() {
        // Test the address latching algorithm
        let mut high_nibble: Option<u8> = None;
        let mut low_nibble: Option<u8> = None;
        let mut full_address_ready = false;
        let mut address_latch_time: Option<Instant> = None;
        let access_time = Duration::from_nanos(100);

        // Mock address handler for testing the algorithm
        struct TestAddressHandler {}

        impl TestAddressHandler {
            fn new() -> Self {
                Self {}
            }
        }

        impl Intel400xAddressHandling for TestAddressHandler {
            fn get_base(&self) -> &BaseComponent {
                unimplemented!("TestAddressHandler doesn't contain BaseComponent")
            }
        }

        let handler = TestAddressHandler::new();

        // First cycle: high nibble
        handler.handle_address_latching(
            0x12,
            &mut high_nibble,
            &mut low_nibble,
            &mut full_address_ready,
            &mut address_latch_time,
            access_time,
        );

        assert_eq!(high_nibble, Some(0x12));
        assert_eq!(low_nibble, None);
        assert_eq!(full_address_ready, false);
        assert_eq!(address_latch_time, None);

        // Second cycle: low nibble
        handler.handle_address_latching(
            0x34,
            &mut high_nibble,
            &mut low_nibble,
            &mut full_address_ready,
            &mut address_latch_time,
            access_time,
        );

        assert_eq!(high_nibble, None); // Should be cleared
        assert_eq!(low_nibble, None); // Should be cleared
        assert_eq!(full_address_ready, true);
        assert!(address_latch_time.is_some());

        // Verify the assembled address
        let assembled = handler.assemble_full_address(Some(0x02), Some(0x04));
        assert_eq!(assembled, Some(0x24));
    }

    #[test]
    fn test_latency_timing_logic() {
        let access_time = Duration::from_nanos(100);

        // Test with no latch time (should return false)
        assert_eq!(
            Intel400xAddressHandling::handle_latency_wait(
                &MockComponent::new(),
                &None,
                access_time
            ),
            false
        );

        thread::sleep(Duration::from_micros(1));

        // Test with recent latch time (should return false if not enough time elapsed)
        let recent_time = Some(Instant::now());
        assert_eq!(
            Intel400xAddressHandling::handle_latency_wait(
                &MockComponent::new(),
                &recent_time,
                access_time
            ),
            true
        );

        // Note: Testing with elapsed time would require sleeping or mocking time
        // This demonstrates the logic structure is correct
    }

    #[test]
    fn test_intel4001_integration_debugging() {
        println!("=== Intel 4001 Integration Test: Setup ===");
        let mut rom = Intel4001::new_with_access_time("TestROM".to_string(), 1); // 1ns for fast testing
        rom.base.set_running(true);

        // Load test data: simple arithmetic sequence
        let test_data = vec![
            0x01, 0x02, 0x03, 0x04, 0x05, 0x10, 0x20, 0x30, 0x40, 0x50, 0xFF,
        ];
        rom.load_rom_data(test_data.clone(), 0).unwrap();

        // Verify test data loaded
        for (i, &data) in test_data.iter().enumerate() {
            assert_eq!(rom.read_rom(i as u8).unwrap(), data);
        }

        // Get pin references
        let sync_pin = rom.get_pin("SYNC").unwrap();
        let cm_pin = rom.get_pin("CM").unwrap();
        let ci_pin = rom.get_pin("CI").unwrap();
        let reset_pin = rom.get_pin("RESET").unwrap();
        let phi1_pin = rom.get_pin("PHI1").unwrap();
        let phi2_pin = rom.get_pin("PHI2").unwrap();
        let d0_pin = rom.get_pin("D0").unwrap();
        let d1_pin = rom.get_pin("D1").unwrap();
        let d2_pin = rom.get_pin("D2").unwrap();
        let d3_pin = rom.get_pin("D3").unwrap();

        // Set settlement time to 0 for immediate testing
        sync_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        cm_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        ci_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        reset_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        phi1_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        phi2_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        d0_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        d1_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        d2_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        d3_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));

        // Initially, all data pins should be HighZ
        assert_eq!(d0_pin.lock().unwrap().read(), PinValue::HighZ);
        assert_eq!(d1_pin.lock().unwrap().read(), PinValue::HighZ);
        assert_eq!(d2_pin.lock().unwrap().read(), PinValue::HighZ);
        assert_eq!(d3_pin.lock().unwrap().read(), PinValue::HighZ);

        // Test reset (RESET is active LOW)
        println!("=== Testing Reset ===");
        {
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);  // Assert reset
        }
        rom.update();
        assert_eq!(rom.get_timing_state(), TimingState::Idle);
        assert_eq!(rom.get_io_mode(), IoMode::Input);

        // Release reset (set HIGH for normal operation)
        {
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);  // Release reset
        }
        rom.update();

        // Test memory read at address 0x00
        println!("=== Memory Access Testing: Address 0x00 ===");
        test_memory_read(
            &mut rom, &sync_pin, &cm_pin, &ci_pin, &phi1_pin, &phi2_pin, &d0_pin, &d1_pin, &d2_pin,
            &d3_pin, 0x00, 0x01,
        );

        // Test memory read at address 0xFF
        // Load test data at address 0xFF specifically
        // Note: Intel 4004 has a 4-bit data bus, so we can only read 4 bits at a time
        // The value 0x0F will be read as 0x0F (low nibble only)
        rom.load_rom_data(vec![0x0F], 0xFF).unwrap();
        println!("=== Memory Access Testing: Address 0xFF ===");
        test_memory_read(
            &mut rom, &sync_pin, &cm_pin, &ci_pin, &phi1_pin, &phi2_pin, &d0_pin, &d1_pin, &d2_pin,
            &d3_pin, 0xFF, 0x0F, // 4-bit value (low nibble only)
        );

        // Test I/O operations
        println!("=== I/O Integration Testing ===");
        // Note: I/O operations on Intel 4001 require proper clock timing and control signals.
        // The handle_io_operation() method requires:
        // - CM (chip_select) = HIGH
        // - CI (io_select) = HIGH
        // - Proper clock edges to trigger the operation

        // For this test, we'll verify the direct I/O port access methods work correctly
        // since full I/O timing simulation would require more complex test setup.

        // Test direct I/O port write (using set_io_port API)
        rom.set_io_mode(IoMode::Output);
        rom.set_io_port(0, 0x05).unwrap();
        assert_eq!(rom.get_io_port(0).unwrap(), 0x05);

        // Test I/O port read (using get_io_port API)
        rom.set_io_port(0, 0x0A).unwrap();
        assert_eq!(rom.get_io_port(0).unwrap(), 0x0A);

        // Test that I/O direction is set to Output when we write
        assert_eq!(rom.get_io_direction(0).unwrap(), IoDirection::Output);

        // Debugging features
        println!("=== Debugging Features ===");
        rom.debug_state_transitions("Integration Test");

        // Pin state snapshots
        println!(
            "Pin states: SYNC: {:?}, CM: {:?}, CI: {:?}, PHI1: {:?}, PHI2: {:?}",
            sync_pin.lock().unwrap().read(),
            cm_pin.lock().unwrap().read(),
            ci_pin.lock().unwrap().read(),
            phi1_pin.lock().unwrap().read(),
            phi2_pin.lock().unwrap().read()
        );

        println!("Test completed successfully!");
    }

    fn test_memory_read(
        rom: &mut Intel4001,
        sync_pin: &Arc<Mutex<Pin>>,
        cm_pin: &Arc<Mutex<Pin>>,
        ci_pin: &Arc<Mutex<Pin>>,
        phi1_pin: &Arc<Mutex<Pin>>,
        phi2_pin: &Arc<Mutex<Pin>>,
        d0_pin: &Arc<Mutex<Pin>>,
        d1_pin: &Arc<Mutex<Pin>>,
        d2_pin: &Arc<Mutex<Pin>>,
        d3_pin: &Arc<Mutex<Pin>>,
        address: u8,
        expected_data: u8,
    ) {
        // Reset to known state first (RESET is active LOW)
        {
            let reset_pin = rom.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);  // Assert reset (active LOW)
        }
        rom.update();
        {
            let reset_pin = rom.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);  // Release reset (HIGH = normal operation)
        }
        rom.update();

        // Set SYNC=1, CM=1, CI=0 for memory read
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        rom.update();

        // Ensure PHI2 is low initially
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        rom.update();

        // Ensure PHI1 is low initially
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        rom.update();

        // Start the component
        rom.base.set_running(true);

        // PHI1 low to high: Address phase for high nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        rom.update();
        assert_eq!(rom.get_timing_state(), TimingState::AddressPhase);

        // Set high nibble on data bus
        rom.write_data_bus((address >> 4) & 0x0F);
        rom.update();

        // PHI1 high to low: Complete address phase for high nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        rom.update();

        // PHI1 low to high again: Address phase for low nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        rom.update();

        // Set low nibble on data bus
        rom.write_data_bus(address & 0x0F);
        rom.update();

        // PHI1 high to low: Complete address phase
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        rom.update();

        // Check if we're in WaitLatency or DriveData state
        // With very small access times, we might transition directly to DriveData
        let state = rom.get_timing_state();
        assert!(
            state == TimingState::WaitLatency || state == TimingState::DriveData,
            "Expected WaitLatency or DriveData, got {:?}",
            state
        );

        // Wait for latency if needed
        if state == TimingState::WaitLatency {
            // Get the actual access time from the ROM
            let access_time_ns = rom.get_access_time();
            thread::sleep(Duration::from_nanos(access_time_ns + 10)); // Add small buffer
            rom.update(); // Update after waiting to check latency
        }

        // Release data bus from test control to allow ROM to drive it
        for i in 0..4 {
            let pin = rom.get_pin(&format!("D{}", i)).unwrap();
            let mut pin_guard = pin.lock().unwrap();
            pin_guard.set_driver(Some("TEST".to_string()), PinValue::HighZ);
        }
        rom.update();

        // PHI2 low to high: Data phase
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        rom.update();
        assert_eq!(rom.get_timing_state(), TimingState::DriveData);

        // Wait a bit for data to be driven
        thread::sleep(Duration::from_nanos(10));
        rom.update(); // Additional update to ensure data is driven on the bus

        // Check data on bus
        let data = rom.read_data_bus();
        assert_eq!(data, expected_data);

        // PHI2 high to low: Cleanup
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        rom.update();
        assert_eq!(rom.get_timing_state(), TimingState::Idle);

        // Tri-state pins
        assert_eq!(d0_pin.lock().unwrap().read(), PinValue::HighZ);
        assert_eq!(d1_pin.lock().unwrap().read(), PinValue::HighZ);
        assert_eq!(d2_pin.lock().unwrap().read(), PinValue::HighZ);
        assert_eq!(d3_pin.lock().unwrap().read(), PinValue::HighZ);
    }

    #[test]
    fn test_minimum_access_time() {
        // Test behavior at minimum access time (200ns) with comprehensive edge cases
        let mut chip = Intel4001::new_with_access_time("MIN_TIME_ROM".to_string(), 200); // 200ns minimum access time
        chip.base.set_running(true);

        // Get pin references
        let sync_pin = chip.get_pin("SYNC").unwrap();
        let cm_pin = chip.get_pin("CM").unwrap();
        let ci_pin = chip.get_pin("CI").unwrap();
        let reset_pin = chip.get_pin("RESET").unwrap();
        let phi1_pin = chip.get_pin("PHI1").unwrap();
        let phi2_pin = chip.get_pin("PHI2").unwrap();
        let d0_pin = chip.get_pin("D0").unwrap();
        let d1_pin = chip.get_pin("D1").unwrap();
        let d2_pin = chip.get_pin("D2").unwrap();
        let d3_pin = chip.get_pin("D3").unwrap();

        // Set settlement time to 0 for immediate testing
        sync_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        cm_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        ci_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        reset_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        phi1_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        phi2_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        d0_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        d1_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        d2_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        d3_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));

        // Test memory read at minimum timing
        // Note: Intel 4004 has a 4-bit data bus, so we can only read 4 bits at a time
        // The full 8-bit read would require M1/M2 cycles (not yet implemented)
        let address = 0x12;
        let expected_data = 0x04; // 4-bit value (low nibble only for single-cycle read)

        // Set up ROM data
        chip.load_rom_data(vec![expected_data], address).unwrap();

        // Test memory read using the helper function
        test_memory_read(
            &mut chip,
            &sync_pin,
            &cm_pin,
            &ci_pin,
            &phi1_pin,
            &phi2_pin,
            &d0_pin,
            &d1_pin,
            &d2_pin,
            &d3_pin,
            address as u8,
            expected_data,
        );

        // Verify state machine transitions correctly at minimum timing
        assert_eq!(chip.get_timing_state(), TimingState::Idle);

        // Test multiple consecutive reads at minimum timing
        // Note: Intel 4004 has a 4-bit data bus, so we can only read 4 bits at a time
        // The expected data must be a 4-bit value (0x00-0x0F)
        for addr in 0x10..0x15 {
            // Use 4-bit values that fit on the data bus
            let expected_data = (addr & 0x0F) as u8; // Low nibble only
            let test_data = vec![expected_data];
            chip.load_rom_data(test_data, addr).unwrap();
            test_memory_read(
                &mut chip,
                &sync_pin,
                &cm_pin,
                &ci_pin,
                &phi1_pin,
                &phi2_pin,
                &d0_pin,
                &d1_pin,
                &d2_pin,
                &d3_pin,
                addr as u8,
                expected_data,
            );
        }

        // Enhanced edge case testing for minimum access time

        // Test edge case: consecutive reads at minimum access time
        // Note: Intel 4004 has a 4-bit data bus, so expected data must be 0-15
        for address in 0x00..0x10 {
            // Use addresses 0x00-0x0F where low nibble equals address
            let expected_data = (address & 0x0F) as u8; // 4-bit value
            let result1 = test_memory_read_edge_case(
                &mut chip,
                &sync_pin,
                &cm_pin,
                &ci_pin,
                &phi1_pin,
                &phi2_pin,
                &d0_pin,
                &d1_pin,
                &d2_pin,
                &d3_pin,
                address as u16,
                expected_data,
            );
            assert_eq!(
                result1, expected_data,
                "Failed consecutive read 1 at address {} at minimum access time",
                address
            );
        }

        // Test edge case: rapid address changes at minimum access time
        // Note: Intel 4004 has a 4-bit data bus, so expected data must be 0-15
        let test_addresses = [0, 255, 128, 1, 254, 2, 253, 3];
        for &address in &test_addresses {
            let expected_data = (address & 0x0F) as u8; // 4-bit value for data bus
            chip.load_rom_data(vec![expected_data], address).unwrap();
            let result = test_memory_read_edge_case(
                &mut chip,
                &sync_pin,
                &cm_pin,
                &ci_pin,
                &phi1_pin,
                &phi2_pin,
                &d0_pin,
                &d1_pin,
                &d2_pin,
                &d3_pin,
                address as u16,
                expected_data,
            );
            assert_eq!(
                result, expected_data,
                "Failed rapid address change test at address {} at minimum access time",
                address
            );
        }

        // Test edge case: minimum access time with I/O operations
        // Note: Intel 4004 has a 4-bit data bus, so expected data must be 0-15
        chip.load_rom_data(vec![0x05], 0x00).unwrap(); // Test pattern (4-bit value)
        chip.load_rom_data(vec![0x0A], 0xFF).unwrap(); // Another test pattern (4-bit value)

        // Test I/O pin behavior during minimum access time reads
        let io_pins = ["IO0", "IO1", "IO2", "IO3"];

        // Set I/O pins to output mode
        for pin_name in &io_pins {
            let _io_pin = chip.get_pin(pin_name).unwrap();
            // Note: In the actual implementation, I/O pin mode is controlled through the chip's I/O methods
            // For this test, we'll verify the I/O functionality through the chip's methods
        }

        // Test memory read while I/O operations are active
        let result = test_memory_read_edge_case(
            &mut chip, &sync_pin, &cm_pin, &ci_pin, &phi1_pin, &phi2_pin, &d0_pin, &d1_pin,
            &d2_pin, &d3_pin, 0x00, 0x05,
        );
        assert_eq!(
            result, 0x05,
            "Failed memory read with active I/O at minimum access time"
        );

        // Test edge case: minimum access time with boundary addresses
        // Note: Intel 4004 has a 4-bit data bus, so expected data must be 0-15
        let boundary_addresses = [0, 1, 254, 255];
        for &address in &boundary_addresses {
            let expected_data = (address & 0x0F) as u8; // 4-bit value for data bus
            chip.load_rom_data(vec![expected_data], address).unwrap();
            let result = test_memory_read_edge_case(
                &mut chip,
                &sync_pin,
                &cm_pin,
                &ci_pin,
                &phi1_pin,
                &phi2_pin,
                &d0_pin,
                &d1_pin,
                &d2_pin,
                &d3_pin,
                address as u16,
                expected_data,
            );
            assert_eq!(
                result, expected_data,
                "Failed boundary address test at {} at minimum access time",
                address
            );
        }

        // Test state machine transitions at minimum access time
        // Verify proper state progression through all phases
        // Note: Intel 4004 has a 4-bit data bus, so we can only read 4 bits at a time
        let mut test_chip = Intel4001::new_with_access_time("STATE_TEST_ROM".to_string(), 200);
        test_chip.base.set_running(true);
        test_chip.load_rom_data(vec![0x02], 0x10).unwrap(); // 4-bit value (low nibble only)

        // Get pins for state machine test
        let test_sync = test_chip.get_pin("SYNC").unwrap();
        let test_cm = test_chip.get_pin("CM").unwrap();
        let test_ci = test_chip.get_pin("CI").unwrap();
        let test_phi1 = test_chip.get_pin("PHI1").unwrap();
        let test_phi2 = test_chip.get_pin("PHI2").unwrap();

        // Set settlement times to 0
        test_sync
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        test_cm
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        test_ci
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        test_phi1
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        test_phi2
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));

        // Initialize PHI2 to Low to ensure proper edge detection
        {
            let mut phi2_guard = test_phi2.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        test_chip.update();

        // Manually step through the state machine to verify timing
        // Set control pins for memory read
        {
            let mut sync_guard = test_sync.lock().unwrap();
            let mut cm_guard = test_cm.lock().unwrap();
            let mut ci_guard = test_ci.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        test_chip.update();
        assert_eq!(test_chip.get_timing_state(), TimingState::Idle);

        // Ensure PHI1 is low initially
        {
            let mut phi1_guard = test_phi1.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        test_chip.update();

        // Start address phase - first PHI1 cycle for high nibble
        {
            let mut phi1_guard = test_phi1.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        test_chip.update();
        assert_eq!(test_chip.get_timing_state(), TimingState::AddressPhase);

        // Apply high nibble
        test_chip.write_data_bus(0x01); // High nibble
        test_chip.update();

        // PHI1 falling edge - latch high nibble
        {
            let mut phi1_guard = test_phi1.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        test_chip.update();
        assert_eq!(test_chip.get_timing_state(), TimingState::AddressPhase); // Still in address phase

        // Second PHI1 cycle for low nibble
        {
            let mut phi1_guard = test_phi1.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        test_chip.update();

        // Apply low nibble
        test_chip.write_data_bus(0x00); // Low nibble
        test_chip.update();

        // PHI1 falling edge - latch low nibble and complete address
        {
            let mut phi1_guard = test_phi1.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        test_chip.update();
        assert_eq!(test_chip.get_timing_state(), TimingState::WaitLatency);

        // Wait for minimum latency (200ns)
        thread::sleep(Duration::from_nanos(210)); // Slightly more than minimum

        // PHI2 high: Data phase
        {
            let mut phi2_guard = test_phi2.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        test_chip.update();
        assert_eq!(test_chip.get_timing_state(), TimingState::DriveData);

        // Verify data is driven correctly (4-bit value)
        let data = test_chip.read_data_bus();
        assert_eq!(data, 0x02);

        // Complete cycle
        {
            let mut phi2_guard = test_phi2.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        test_chip.update();
        assert_eq!(test_chip.get_timing_state(), TimingState::Idle);

        // Test edge case: timing violations at minimum access time
        // Test what happens when we try to read too quickly
        let mut fast_chip = Intel4001::new_with_access_time("FAST_VIOLATION_ROM".to_string(), 200);
        fast_chip.base.set_running(true);
        fast_chip.load_rom_data(vec![0x09], 0x50).unwrap(); // Use 4-bit value (0x09)

        let fast_sync = fast_chip.get_pin("SYNC").unwrap();
        let fast_cm = fast_chip.get_pin("CM").unwrap();
        let fast_ci = fast_chip.get_pin("CI").unwrap();
        let fast_phi1 = fast_chip.get_pin("PHI1").unwrap();
        let fast_phi2 = fast_chip.get_pin("PHI2").unwrap();

        // Set settlement times to 0
        fast_sync
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        fast_cm
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        fast_ci
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        fast_phi1
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        fast_phi2
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));

        // Initialize PHI2 to Low to ensure proper edge detection
        {
            let mut phi2_guard = fast_phi2.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        fast_chip.update();

        // Set up for memory read
        {
            let mut sync_guard = fast_sync.lock().unwrap();
            let mut cm_guard = fast_cm.lock().unwrap();
            let mut ci_guard = fast_ci.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        fast_chip.update();

        // Ensure PHI1 is low initially
        {
            let mut phi1_guard = fast_phi1.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        fast_chip.update();

        // First PHI1 cycle - latch high nibble
        {
            let mut phi1_guard = fast_phi1.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        fast_chip.update();

        // Apply high nibble
        fast_chip.write_data_bus(0x05); // High nibble of address 0x50
        fast_chip.update();

        // PHI1 falling edge - latch high nibble
        {
            let mut phi1_guard = fast_phi1.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        fast_chip.update();

        // Second PHI1 cycle - latch low nibble
        {
            let mut phi1_guard = fast_phi1.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        fast_chip.update();

        // Apply low nibble
        fast_chip.write_data_bus(0x00); // Low nibble of address 0x50
        fast_chip.update();

        // PHI1 falling edge - latch low nibble and complete address
        {
            let mut phi1_guard = fast_phi1.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        fast_chip.update();

        // At this point, the state should be WaitLatency or DriveData
        let state = fast_chip.get_timing_state();
        assert!(
            state == TimingState::WaitLatency || state == TimingState::DriveData,
            "Expected WaitLatency or DriveData, got {:?}",
            state
        );

        // Release data bus from test control to allow ROM to drive it
        for i in 0..4 {
            let pin = fast_chip.get_pin(&format!("D{}", i)).unwrap();
            let mut pin_guard = pin.lock().unwrap();
            pin_guard.set_driver(Some("TEST".to_string()), PinValue::HighZ);
        }
        fast_chip.update();

        // Try to read data - PHI2 rising edge triggers data driving if latency elapsed
        {
            let mut phi2_guard = fast_phi2.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        fast_chip.update();

        // Wait for proper timing and then verify data
        thread::sleep(Duration::from_nanos(210));
        fast_chip.update();

        // Now data should be valid (4-bit value)
        let data = fast_chip.read_data_bus();
        assert_eq!(data, 0x09);
    }

    // Helper function for edge case memory read testing
    fn test_memory_read_edge_case(
        chip: &mut Intel4001,
        sync_pin: &Arc<Mutex<Pin>>,
        cm_pin: &Arc<Mutex<Pin>>,
        ci_pin: &Arc<Mutex<Pin>>,
        phi1_pin: &Arc<Mutex<Pin>>,
        phi2_pin: &Arc<Mutex<Pin>>,
        _d0_pin: &Arc<Mutex<Pin>>,
        _d1_pin: &Arc<Mutex<Pin>>,
        _d2_pin: &Arc<Mutex<Pin>>,
        _d3_pin: &Arc<Mutex<Pin>>,
        address: u16,
        expected_data: u8,
    ) -> u8 {
        // Load the expected data into ROM at the specified address
        chip.load_rom_data(vec![expected_data], address as usize)
            .unwrap();

        // Reset to known state
        chip.perform_reset();
        chip.update();

        // Start the component
        chip.base.set_running(true);

        // Set control pins for memory read
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI2 is low initially
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI1 is low initially
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // PHI1 low to high: Address phase for high nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set high nibble on data bus
        chip.write_data_bus(((address >> 4) & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Complete address phase for high nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // PHI1 low to high again: Address phase for low nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set low nibble on data bus
        chip.write_data_bus((address & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Complete address phase
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Wait for the address to be fully latched and state to transition
        thread::sleep(Duration::from_nanos(10));
        chip.update();

        // Check if we're in WaitLatency or DriveData state
        // With very small access times, we might transition directly to DriveData
        let state = chip.get_timing_state();
        assert!(
            state == TimingState::WaitLatency || state == TimingState::DriveData,
            "Expected WaitLatency or DriveData, got {:?}",
            state
        );

        // Wait for latency if needed
        let current_state = chip.get_timing_state();
        if current_state == TimingState::WaitLatency {
            // Get the actual access time from the ROM
            let access_time_ns = chip.get_access_time();
            thread::sleep(Duration::from_nanos(access_time_ns + 10)); // Add small buffer
            chip.update(); // Update after waiting to check latency
        }

        // Release data bus from test control to allow ROM to drive it
        for i in 0..4 {
            let pin = chip.get_pin(&format!("D{}", i)).unwrap();
            let mut pin_guard = pin.lock().unwrap();
            pin_guard.set_driver(Some("TEST".to_string()), PinValue::HighZ);
        }
        chip.update();

        // PHI2 low to high: Data phase
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();
        assert_eq!(chip.get_timing_state(), TimingState::DriveData);

        // Wait a bit for data to be driven
        thread::sleep(Duration::from_nanos(10));
        chip.update(); // Additional update to ensure data is driven on the bus

        // Check data on bus
        let data = chip.read_data_bus();

        // PHI2 high to low: Cleanup
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();
        assert_eq!(chip.get_timing_state(), TimingState::Idle);

        data
    }

    #[test]
    fn test_maximum_access_time() {
        // Test behavior at maximum access time (750ns)
        let mut chip = Intel4001::new_with_access_time("MAX_TIME_ROM".to_string(), 750); // 750ns maximum access time
        chip.base.set_running(true);

        // Get pin references
        let sync_pin = chip.get_pin("SYNC").unwrap();
        let cm_pin = chip.get_pin("CM").unwrap();
        let ci_pin = chip.get_pin("CI").unwrap();
        let reset_pin = chip.get_pin("RESET").unwrap();
        let phi1_pin = chip.get_pin("PHI1").unwrap();
        let phi2_pin = chip.get_pin("PHI2").unwrap();
        let d0_pin = chip.get_pin("D0").unwrap();
        let d1_pin = chip.get_pin("D1").unwrap();
        let d2_pin = chip.get_pin("D2").unwrap();
        let d3_pin = chip.get_pin("D3").unwrap();

        // Set settlement time to 0 for immediate testing
        sync_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        cm_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        ci_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        reset_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        phi1_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        phi2_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        d0_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        d1_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        d2_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        d3_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));

        // Test memory read at maximum timing
        // Note: Intel 4004 has a 4-bit data bus, so we can only read 4 bits at a time
        let address = 0x23;
        let expected_data = 0x05; // 4-bit value (low nibble only)

        // Set up ROM data
        chip.load_rom_data(vec![expected_data], address).unwrap();

        // Test memory read using the helper function
        test_memory_read(
            &mut chip,
            &sync_pin,
            &cm_pin,
            &ci_pin,
            &phi1_pin,
            &phi2_pin,
            &d0_pin,
            &d1_pin,
            &d2_pin,
            &d3_pin,
            address as u8,
            expected_data,
        );

        // Verify state machine transitions correctly at maximum timing
        assert_eq!(chip.get_timing_state(), TimingState::Idle);

        // Test multiple consecutive reads at maximum timing
        for addr in 0x20..0x25 {
            let test_data = vec![addr as u8];
            chip.load_rom_data(test_data, addr).unwrap();
            test_memory_read(
                &mut chip, &sync_pin, &cm_pin, &ci_pin, &phi1_pin, &phi2_pin, &d0_pin, &d1_pin,
                &d2_pin, &d3_pin, addr as u8, addr as u8,
            );
        }

        // Enhanced edge case testing for maximum access time

        // Test edge case: consecutive reads at maximum access time
        for address in 0x40..0x50 {
            chip.load_rom_data(vec![address as u8], address).unwrap();
            let result1 = test_memory_read_edge_case_max(
                &mut chip,
                &sync_pin,
                &cm_pin,
                &ci_pin,
                &phi1_pin,
                &phi2_pin,
                &d0_pin,
                &d1_pin,
                &d2_pin,
                &d3_pin,
                address as u16,
                address as u8,
            );
            assert_eq!(
                result1, address as u8,
                "Failed consecutive read 1 at address {} at maximum access time",
                address
            );
        }

        // Test edge case: rapid address changes at maximum access time
        let test_addresses = [0, 255, 128, 1, 254, 2, 253, 3];
        for &address in &test_addresses {
            chip.load_rom_data(vec![address as u8], address).unwrap();
            let result = test_memory_read_edge_case_max(
                &mut chip,
                &sync_pin,
                &cm_pin,
                &ci_pin,
                &phi1_pin,
                &phi2_pin,
                &d0_pin,
                &d1_pin,
                &d2_pin,
                &d3_pin,
                address as u16,
                address as u8,
            );
            assert_eq!(
                result, address as u8,
                "Failed rapid address change test at address {} at maximum access time",
                address
            );
        }

        // Test edge case: maximum access time with I/O operations
        chip.load_rom_data(vec![0x33], 0x00).unwrap(); // Test pattern
        chip.load_rom_data(vec![0xCC], 0xFF).unwrap(); // Another test pattern

        // Test I/O pin behavior during maximum access time reads
        let io_pins = ["IO0", "IO1", "IO2", "IO3"];

        // Set I/O pins to output mode
        for pin_name in &io_pins {
            let _io_pin = chip.get_pin(pin_name).unwrap();
            // Note: In the actual implementation, I/O pin mode is controlled through the chip's I/O methods
            // For this test, we'll verify the I/O functionality through the chip's methods
        }

        // Test memory read while I/O operations are active
        let result = test_memory_read_edge_case_max(
            &mut chip, &sync_pin, &cm_pin, &ci_pin, &phi1_pin, &phi2_pin, &d0_pin, &d1_pin,
            &d2_pin, &d3_pin, 0x00, 0x33,
        );
        assert_eq!(
            result, 0x33,
            "Failed memory read with active I/O at maximum access time"
        );

        // Test edge case: maximum access time with boundary addresses
        let boundary_addresses = [0, 1, 254, 255];
        for &address in &boundary_addresses {
            chip.load_rom_data(vec![address as u8], address).unwrap();
            let result = test_memory_read_edge_case_max(
                &mut chip,
                &sync_pin,
                &cm_pin,
                &ci_pin,
                &phi1_pin,
                &phi2_pin,
                &d0_pin,
                &d1_pin,
                &d2_pin,
                &d3_pin,
                address as u16,
                address as u8,
            );
            assert_eq!(
                result, address as u8,
                "Failed boundary address test at {} at maximum access time",
                address
            );
        }

        // Test state machine transitions at maximum access time
        // Verify proper state progression through all phases
        let mut test_chip = Intel4001::new_with_access_time("MAX_STATE_TEST_ROM".to_string(), 750);
        test_chip.base.set_running(true);
        test_chip.load_rom_data(vec![0x87], 0x20).unwrap();

        // Get pins for state machine test
        let test_sync = test_chip.get_pin("SYNC").unwrap();
        let test_cm = test_chip.get_pin("CM").unwrap();
        let test_ci = test_chip.get_pin("CI").unwrap();
        let test_phi1 = test_chip.get_pin("PHI1").unwrap();
        let test_phi2 = test_chip.get_pin("PHI2").unwrap();

        // Set settlement times to 0
        test_sync
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        test_cm
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        test_ci
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        test_phi1
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        test_phi2
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));

        // Manually step through the state machine to verify timing
        // Set control pins for memory read
        {
            let mut sync_guard = test_sync.lock().unwrap();
            let mut cm_guard = test_cm.lock().unwrap();
            let mut ci_guard = test_ci.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        test_chip.update();
        assert_eq!(test_chip.get_timing_state(), TimingState::Idle);

        // Start address phase
        {
            let mut phi1_guard = test_phi1.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        test_chip.update();
        assert_eq!(test_chip.get_timing_state(), TimingState::AddressPhase);

        // Apply address
        test_chip.write_data_bus(0x02); // High nibble
        test_chip.update();
        test_chip.write_data_bus(0x00); // Low nibble
        test_chip.update();

        // Complete address phase
        {
            let mut phi1_guard = test_phi1.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        test_chip.update();
        assert_eq!(test_chip.get_timing_state(), TimingState::WaitLatency);

        // Wait for maximum latency (750ns)
        thread::sleep(Duration::from_nanos(760)); // Slightly more than maximum

        // PHI2 high: Data phase
        {
            let mut phi2_guard = test_phi2.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        test_chip.update();
        assert_eq!(test_chip.get_timing_state(), TimingState::DriveData);

        // Verify data is driven correctly
        let data = test_chip.read_data_bus();
        assert_eq!(data, 0x87);

        // Complete cycle
        {
            let mut phi2_guard = test_phi2.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        test_chip.update();
        assert_eq!(test_chip.get_timing_state(), TimingState::Idle);

        // Test edge case: timing violations at maximum access time
        // Test what happens when we try to read too quickly even at maximum access time
        let mut slow_chip = Intel4001::new_with_access_time("SLOW_VIOLATION_ROM".to_string(), 750);
        slow_chip.base.set_running(true);
        slow_chip.load_rom_data(vec![0xBB], 0x60).unwrap();

        let slow_sync = slow_chip.get_pin("SYNC").unwrap();
        let slow_cm = slow_chip.get_pin("CM").unwrap();
        let slow_ci = slow_chip.get_pin("CI").unwrap();
        let slow_phi1 = slow_chip.get_pin("PHI1").unwrap();
        let slow_phi2 = slow_chip.get_pin("PHI2").unwrap();

        // Set settlement times to 0
        slow_sync
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        slow_cm
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        slow_ci
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        slow_phi1
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        slow_phi2
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));

        // Set up for memory read
        {
            let mut sync_guard = slow_sync.lock().unwrap();
            let mut cm_guard = slow_cm.lock().unwrap();
            let mut ci_guard = slow_ci.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        slow_chip.update();

        // Start address phase
        {
            let mut phi1_guard = slow_phi1.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        slow_chip.update();

        // Apply address quickly
        slow_chip.write_data_bus(0x06); // High nibble
        slow_chip.update();
        slow_chip.write_data_bus(0x00); // Low nibble
        slow_chip.update();

        // Complete address phase
        {
            let mut phi1_guard = slow_phi1.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        slow_chip.update();

        // Try to read data immediately without waiting for maximum latency
        {
            let mut phi2_guard = slow_phi2.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        slow_chip.update();

        // At maximum access time, the chip should still be in WaitLatency
        let state = slow_chip.get_timing_state();
        assert!(
            state == TimingState::WaitLatency || state == TimingState::DriveData,
            "Expected WaitLatency or DriveData, got {:?}",
            state
        );

        // Wait for proper timing and then verify data
        thread::sleep(Duration::from_nanos(760));
        slow_chip.update();

        // Now data should be valid
        let data = slow_chip.read_data_bus();
        assert_eq!(data, 0xBB);

        // Test edge case: clock stretching at maximum access time
        // Test what happens when clock edges are delayed
        let mut stretch_chip = Intel4001::new_with_access_time("STRETCH_ROM".to_string(), 750);
        stretch_chip.base.set_running(true);
        stretch_chip.load_rom_data(vec![0xDD], 0x70).unwrap();

        let stretch_sync = stretch_chip.get_pin("SYNC").unwrap();
        let stretch_cm = stretch_chip.get_pin("CM").unwrap();
        let stretch_ci = stretch_chip.get_pin("CI").unwrap();
        let stretch_phi1 = stretch_chip.get_pin("PHI1").unwrap();
        let stretch_phi2 = stretch_chip.get_pin("PHI2").unwrap();

        // Set settlement times to 0
        stretch_sync
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        stretch_cm
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        stretch_ci
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        stretch_phi1
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        stretch_phi2
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));

        // Set up for memory read
        {
            let mut sync_guard = stretch_sync.lock().unwrap();
            let mut cm_guard = stretch_cm.lock().unwrap();
            let mut ci_guard = stretch_ci.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        stretch_chip.update();

        // Start address phase with stretched clock
        {
            let mut phi1_guard = stretch_phi1.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        stretch_chip.update();

        // Apply address with delays between nibbles
        stretch_chip.write_data_bus(0x07); // High nibble
        thread::sleep(Duration::from_nanos(100)); // Delay between nibbles
        stretch_chip.update();
        stretch_chip.write_data_bus(0x00); // Low nibble
        thread::sleep(Duration::from_nanos(100)); // Delay after low nibble
        stretch_chip.update();

        // Complete address phase with stretched clock
        {
            let mut phi1_guard = stretch_phi1.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        stretch_chip.update();

        // Wait for maximum latency with additional stretching
        thread::sleep(Duration::from_nanos(800)); // More than maximum

        // PHI2 high with stretched clock: Data phase
        {
            let mut phi2_guard = stretch_phi2.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        stretch_chip.update();

        // Verify data is driven correctly even with clock stretching
        let data = stretch_chip.read_data_bus();
        assert_eq!(data, 0xDD);

        // Complete cycle
        {
            let mut phi2_guard = stretch_phi2.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        stretch_chip.update();
        assert_eq!(stretch_chip.get_timing_state(), TimingState::Idle);
    }

    // Helper function for edge case memory read testing at maximum access time
    fn test_memory_read_edge_case_max(
        chip: &mut Intel4001,
        sync_pin: &Arc<Mutex<Pin>>,
        cm_pin: &Arc<Mutex<Pin>>,
        ci_pin: &Arc<Mutex<Pin>>,
        phi1_pin: &Arc<Mutex<Pin>>,
        phi2_pin: &Arc<Mutex<Pin>>,
        _d0_pin: &Arc<Mutex<Pin>>,
        _d1_pin: &Arc<Mutex<Pin>>,
        _d2_pin: &Arc<Mutex<Pin>>,
        _d3_pin: &Arc<Mutex<Pin>>,
        address: u16,
        _expected_data: u8,
    ) -> u8 {
        // Reset to known state (RESET is active LOW)
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);  // Assert reset
        }
        chip.update();
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);  // Release reset
        }
        chip.update();

        // Set control pins for memory read
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI2 is low initially
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI1 is low initially
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // PHI1 low to high: Address phase for high nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set high nibble on data bus
        chip.write_data_bus(((address >> 4) & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Latch high nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // PHI1 low to high again: Address phase for low nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set low nibble on data bus
        chip.write_data_bus((address & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Latch low nibble and complete address
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Wait for maximum access time (750ns)
        thread::sleep(Duration::from_nanos(760));

        // Release data bus from test control to allow ROM to drive it
        for i in 0..4 {
            let pin = chip.get_pin(&format!("D{}", i)).unwrap();
            let mut pin_guard = pin.lock().unwrap();
            pin_guard.set_driver(Some("TEST".to_string()), PinValue::HighZ);
        }
        chip.update();

        // PHI2 low to high: Data phase
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Wait for data to be driven
        thread::sleep(Duration::from_nanos(10));

        // Read data
        let data = chip.read_data_bus();

        // PHI2 high to low: Cleanup
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        data
    }

    #[test]
    fn test_address_setup_hold_times() {
        // Test address setup and hold timing requirements with comprehensive edge cases
        let mut chip = Intel4001::new_with_access_time("SETUP_HOLD_ROM".to_string(), 500); // Standard access time
        chip.base.set_running(true);

        // Get pin references
        let sync_pin = chip.get_pin("SYNC").unwrap();
        let cm_pin = chip.get_pin("CM").unwrap();
        let ci_pin = chip.get_pin("CI").unwrap();
        let reset_pin = chip.get_pin("RESET").unwrap();
        let phi1_pin = chip.get_pin("PHI1").unwrap();
        let phi2_pin = chip.get_pin("PHI2").unwrap();
        let d0_pin = chip.get_pin("D0").unwrap();
        let d1_pin = chip.get_pin("D1").unwrap();
        let d2_pin = chip.get_pin("D2").unwrap();
        let d3_pin = chip.get_pin("D3").unwrap();

        // Set settlement time to 0 for immediate testing
        sync_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        cm_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        ci_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        reset_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        phi1_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        phi2_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        d0_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        d1_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        d2_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        d3_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));

        // Test address setup time (minimum 100ns before PHI2 rising edge)
        // Note: Intel 4004 has a 4-bit data bus, so we can only read 4 bits at a time
        let address = 0x34;
        let expected_data = 0x06; // 4-bit value (low nibble only)

        // Set up ROM data
        chip.load_rom_data(vec![expected_data], address).unwrap();

        // Test memory read using the helper function
        test_memory_read(
            &mut chip,
            &sync_pin,
            &cm_pin,
            &ci_pin,
            &phi1_pin,
            &phi2_pin,
            &d0_pin,
            &d1_pin,
            &d2_pin,
            &d3_pin,
            address as u8,
            expected_data,
        );

        // Test multiple address setup/hold scenarios
        for test_addr in 0x30..0x35 {
            let test_data = vec![test_addr as u8 * 2];
            chip.load_rom_data(test_data, test_addr).unwrap();
            test_memory_read(
                &mut chip,
                &sync_pin,
                &cm_pin,
                &ci_pin,
                &phi1_pin,
                &phi2_pin,
                &d0_pin,
                &d1_pin,
                &d2_pin,
                &d3_pin,
                test_addr as u8,
                test_addr as u8 * 2,
            );
        }

        // Enhanced edge case testing for address setup and hold times

        // Test edge case: minimum address setup time (100ns)
        // Address must be stable for at least 100ns before PHI2 rising edge
        let setup_test_addresses = [0x10, 0x20, 0x30, 0x40, 0x50];
        for &test_addr in &setup_test_addresses {
            chip.load_rom_data(vec![test_addr as u8], test_addr)
                .unwrap();

            // Test with minimum setup time
            let result = test_address_setup_time(
                &mut chip,
                &sync_pin,
                &cm_pin,
                &ci_pin,
                &phi1_pin,
                &phi2_pin,
                test_addr as u16,
                100,
            ); // 100ns setup time
            assert_eq!(
                result, test_addr as u8,
                "Failed minimum setup time test at address {}",
                test_addr
            );
        }

        // Test edge case: address hold time after PHI2 rising edge
        // Address must remain stable for at least 50ns after PHI2 rising edge
        let hold_test_addresses = [0x11, 0x21, 0x31, 0x41, 0x51];
        for &test_addr in &hold_test_addresses {
            chip.load_rom_data(vec![test_addr as u8], test_addr)
                .unwrap();

            // Test with minimum hold time
            let result = test_address_hold_time(
                &mut chip,
                &sync_pin,
                &cm_pin,
                &ci_pin,
                &phi1_pin,
                &phi2_pin,
                test_addr as u16,
                50,
            ); // 50ns hold time
            assert_eq!(
                result, test_addr as u8,
                "Failed minimum hold time test at address {}",
                test_addr
            );
        }

        // Test edge case: address setup time violations
        // Test what happens when address changes too close to PHI2 rising edge
        let mut violation_chip = Intel4001::new_with_access_time("VIOLATION_ROM".to_string(), 500);
        violation_chip.base.set_running(true);
        violation_chip.load_rom_data(vec![0x99], 0x60).unwrap();

        let violation_sync = violation_chip.get_pin("SYNC").unwrap();
        let violation_cm = violation_chip.get_pin("CM").unwrap();
        let violation_ci = violation_chip.get_pin("CI").unwrap();
        let violation_phi1 = violation_chip.get_pin("PHI1").unwrap();
        let violation_phi2 = violation_chip.get_pin("PHI2").unwrap();

        // Set settlement times to 0
        violation_sync
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        violation_cm
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        violation_ci
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        violation_phi1
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        violation_phi2
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));

        // Test setup time violation
        let result = test_address_setup_time(
            &mut violation_chip,
            &violation_sync,
            &violation_cm,
            &violation_ci,
            &violation_phi1,
            &violation_phi2,
            0x60,
            50,
        ); // Only 50ns setup time (violation)
           // The chip might still work due to implementation tolerances, but this tests the edge case
        println!("Setup time violation test result: 0x{:02x}", result);

        // Test edge case: address hold time violations
        // Test what happens when address changes too soon after PHI2 rising edge
        let result = test_address_hold_time(
            &mut violation_chip,
            &violation_sync,
            &violation_cm,
            &violation_ci,
            &violation_phi1,
            &violation_phi2,
            0x60,
            25,
        ); // Only 25ns hold time (violation)
           // The chip might still work due to implementation tolerances, but this tests the edge case
        println!("Hold time violation test result: 0x{:02x}", result);

        // Test edge case: address stability during both setup and hold
        let stability_test_addresses = [0x70, 0x71, 0x72, 0x73, 0x74];
        for &test_addr in &stability_test_addresses {
            chip.load_rom_data(vec![test_addr as u8], test_addr)
                .unwrap();

            // Test with both setup and hold times
            let result = test_address_stability(
                &mut chip,
                &sync_pin,
                &cm_pin,
                &ci_pin,
                &phi1_pin,
                &phi2_pin,
                test_addr as u16,
                100,
                50,
            ); // 100ns setup, 50ns hold
            assert_eq!(
                result, test_addr as u8,
                "Failed address stability test at address {}",
                test_addr
            );
        }

        // Test edge case: address transitions at different phases
        // Test address changes during different clock phases
        let phase_test_addresses = [0x80, 0x81, 0x82, 0x83];
        for &test_addr in &phase_test_addresses {
            chip.load_rom_data(vec![test_addr as u8], test_addr)
                .unwrap();

            // Test address transition during PHI1 high
            let result1 = test_address_transition_timing(
                &mut chip,
                &sync_pin,
                &cm_pin,
                &ci_pin,
                &phi1_pin,
                &phi2_pin,
                test_addr as u16,
                "PHI1_HIGH",
            );
            assert_eq!(
                result1, test_addr as u8,
                "Failed address transition during PHI1_HIGH at address {}",
                test_addr
            );

            // Test address transition during PHI1 low
            let result2 = test_address_transition_timing(
                &mut chip,
                &sync_pin,
                &cm_pin,
                &ci_pin,
                &phi1_pin,
                &phi2_pin,
                test_addr as u16,
                "PHI1_LOW",
            );
            assert_eq!(
                result2, test_addr as u8,
                "Failed address transition during PHI1_LOW at address {}",
                test_addr
            );
        }

        // Test edge case: address nibble timing
        // Test timing between high and low nibble latching
        let nibble_test_addresses = [0x90, 0x91, 0x92, 0x93];
        for &test_addr in &nibble_test_addresses {
            chip.load_rom_data(vec![test_addr as u8], test_addr)
                .unwrap();

            // Test with different delays between nibbles
            for nibble_delay in [0, 50, 100, 200] {
                let result = test_nibble_timing(
                    &mut chip,
                    &sync_pin,
                    &cm_pin,
                    &ci_pin,
                    &phi1_pin,
                    &phi2_pin,
                    test_addr as u16,
                    nibble_delay,
                );
                assert_eq!(
                    result, test_addr as u8,
                    "Failed nibble timing test with {}ns delay at address {}",
                    nibble_delay, test_addr
                );
            }
        }

        // Test edge case: address setup with I/O operations
        // Test address timing when I/O operations are active
        chip.load_rom_data(vec![0xA5], 0xA0).unwrap();
        chip.set_io_mode(IoMode::Output);
        chip.set_io_direction(0, IoDirection::Output).unwrap();
        chip.set_io_port(0, 0x0F).unwrap();

        let result = test_address_setup_with_io(
            &mut chip, &sync_pin, &cm_pin, &ci_pin, &phi1_pin, &phi2_pin, 0xA0, 100,
        );
        assert_eq!(result, 0xA5, "Failed address setup with active I/O");

        // Test edge case: address setup at different clock frequencies
        // Test address timing with different clock periods
        let clock_periods = [100, 200, 500, 1000]; // ns
        for &period in &clock_periods {
            chip.load_rom_data(vec![0xB0 + (period / 100) as u8], 0xB0)
                .unwrap();

            let result = test_address_setup_with_clock_period(
                &mut chip, &sync_pin, &cm_pin, &ci_pin, &phi1_pin, &phi2_pin, 0xB0, 100, period,
            );
            assert_eq!(
                result,
                0xB0 + (period / 100) as u8,
                "Failed address setup with clock period {}ns",
                period
            );
        }
    }

    // Helper function for testing address setup time
    fn test_address_setup_time(
        chip: &mut Intel4001,
        sync_pin: &Arc<Mutex<Pin>>,
        cm_pin: &Arc<Mutex<Pin>>,
        ci_pin: &Arc<Mutex<Pin>>,
        phi1_pin: &Arc<Mutex<Pin>>,
        phi2_pin: &Arc<Mutex<Pin>>,
        address: u16,
        setup_time_ns: u64,
    ) -> u8 {
        // Reset to known state (RESET is active LOW)
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);  // Assert reset
        }
        chip.update();
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);  // Release reset
        }
        chip.update();

        // Set control pins for memory read
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI2 is low initially
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI1 is low initially
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // PHI1 low to high: Address phase for high nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set high nibble on data bus
        chip.write_data_bus(((address >> 4) & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Latch high nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // PHI1 low to high again: Address phase for low nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set low nibble on data bus
        chip.write_data_bus((address & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Latch low nibble and complete address
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Wait for specified setup time
        thread::sleep(Duration::from_nanos(setup_time_ns));

        // Release data bus from test control to allow ROM to drive it
        for i in 0..4 {
            let pin = chip.get_pin(&format!("D{}", i)).unwrap();
            let mut pin_guard = pin.lock().unwrap();
            pin_guard.set_driver(Some("TEST".to_string()), PinValue::HighZ);
        }
        chip.update();

        // PHI2 low to high: Data phase
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Wait for access time
        thread::sleep(Duration::from_nanos(510)); // Slightly more than access time

        // Read data
        let data = chip.read_data_bus();

        // PHI2 high to low: Cleanup
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        data
    }

    // Helper function for testing address hold time
    fn test_address_hold_time(
        chip: &mut Intel4001,
        sync_pin: &Arc<Mutex<Pin>>,
        cm_pin: &Arc<Mutex<Pin>>,
        ci_pin: &Arc<Mutex<Pin>>,
        phi1_pin: &Arc<Mutex<Pin>>,
        phi2_pin: &Arc<Mutex<Pin>>,
        address: u16,
        hold_time_ns: u64,
    ) -> u8 {
        // Reset to known state (RESET is active LOW)
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);  // Assert reset
        }
        chip.update();
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);  // Release reset
        }
        chip.update();

        // Set control pins for memory read
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI2 is low initially
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI1 is low initially
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // PHI1 low to high: Address phase for high nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set high nibble on data bus
        chip.write_data_bus(((address >> 4) & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Latch high nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // PHI1 low to high again: Address phase for low nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set low nibble on data bus
        chip.write_data_bus((address & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Latch low nibble and complete address
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Wait for access time
        thread::sleep(Duration::from_nanos(510)); // Slightly more than access time

        // Release data bus from test control to allow ROM to drive it
        for i in 0..4 {
            let pin = chip.get_pin(&format!("D{}", i)).unwrap();
            let mut pin_guard = pin.lock().unwrap();
            pin_guard.set_driver(Some("TEST".to_string()), PinValue::HighZ);
        }
        chip.update();

        // PHI2 low to high: Data phase
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Wait for specified hold time
        thread::sleep(Duration::from_nanos(hold_time_ns));

        // Read data
        let data = chip.read_data_bus();

        // PHI2 high to low: Cleanup
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        data
    }

    // Helper function for testing address stability
    fn test_address_stability(
        chip: &mut Intel4001,
        sync_pin: &Arc<Mutex<Pin>>,
        cm_pin: &Arc<Mutex<Pin>>,
        ci_pin: &Arc<Mutex<Pin>>,
        phi1_pin: &Arc<Mutex<Pin>>,
        phi2_pin: &Arc<Mutex<Pin>>,
        address: u16,
        setup_time_ns: u64,
        hold_time_ns: u64,
    ) -> u8 {
        // Reset to known state (RESET is active LOW)
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);  // Assert reset
        }
        chip.update();
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);  // Release reset
        }
        chip.update();

        // Set control pins for memory read
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI2 is low initially
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI1 is low initially
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // PHI1 low to high: Address phase for high nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set high nibble on data bus
        chip.write_data_bus(((address >> 4) & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Latch high nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // PHI1 low to high again: Address phase for low nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set low nibble on data bus
        chip.write_data_bus((address & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Latch low nibble and complete address
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Wait for setup time
        thread::sleep(Duration::from_nanos(setup_time_ns));

        // Release data bus from test control to allow ROM to drive it
        for i in 0..4 {
            let pin = chip.get_pin(&format!("D{}", i)).unwrap();
            let mut pin_guard = pin.lock().unwrap();
            pin_guard.set_driver(Some("TEST".to_string()), PinValue::HighZ);
        }
        chip.update();

        // PHI2 low to high: Data phase
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Wait for access time
        thread::sleep(Duration::from_nanos(510)); // Slightly more than access time

        // Wait for hold time
        thread::sleep(Duration::from_nanos(hold_time_ns));

        // Read data
        let data = chip.read_data_bus();

        // PHI2 high to low: Cleanup
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        data
    }

    // Helper function for testing address transition timing
    fn test_address_transition_timing(
        chip: &mut Intel4001,
        sync_pin: &Arc<Mutex<Pin>>,
        cm_pin: &Arc<Mutex<Pin>>,
        ci_pin: &Arc<Mutex<Pin>>,
        phi1_pin: &Arc<Mutex<Pin>>,
        phi2_pin: &Arc<Mutex<Pin>>,
        address: u16,
        phase: &str,
    ) -> u8 {
        // Reset to known state (RESET is active LOW)
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);  // Assert reset
        }
        chip.update();
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);  // Release reset
        }
        chip.update();

        // Set control pins for memory read
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI2 is low initially
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI1 is low initially
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        match phase {
            "PHI1_HIGH" => {
                // PHI1 low to high: Address phase for high nibble
                {
                    let mut phi1_guard = phi1_pin.lock().unwrap();
                    phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
                }
                chip.update();

                // Set high nibble during PHI1 high
                chip.write_data_bus(((address >> 4) & 0x0F) as u8);
                chip.update();

                // PHI1 high to low: Latch high nibble
                {
                    let mut phi1_guard = phi1_pin.lock().unwrap();
                    phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
                }
                chip.update();

                // PHI1 low to high again: Address phase for low nibble
                {
                    let mut phi1_guard = phi1_pin.lock().unwrap();
                    phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
                }
                chip.update();

                // Set low nibble during PHI1 high
                chip.write_data_bus((address & 0x0F) as u8);
                chip.update();

                // PHI1 high to low: Latch low nibble and complete address
                {
                    let mut phi1_guard = phi1_pin.lock().unwrap();
                    phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
                }
                chip.update();
            }
            "PHI1_LOW" => {
                // Set PHI1 high first
                {
                    let mut phi1_guard = phi1_pin.lock().unwrap();
                    phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
                }
                chip.update();

                // Set PHI1 low - this latches whatever was on the bus
                {
                    let mut phi1_guard = phi1_pin.lock().unwrap();
                    phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
                }
                chip.update();

                // Set high nibble during PHI1 low - won't be latched yet
                chip.write_data_bus(((address >> 4) & 0x0F) as u8);
                chip.update();

                // PHI1 low to high: Next address phase cycle
                {
                    let mut phi1_guard = phi1_pin.lock().unwrap();
                    phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
                }
                chip.update();

                // PHI1 high to low: Latch high nibble
                {
                    let mut phi1_guard = phi1_pin.lock().unwrap();
                    phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
                }
                chip.update();

                // Set low nibble
                chip.write_data_bus((address & 0x0F) as u8);
                chip.update();

                // PHI1 low to high again
                {
                    let mut phi1_guard = phi1_pin.lock().unwrap();
                    phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
                }
                chip.update();

                // PHI1 high to low: Latch low nibble and complete address
                {
                    let mut phi1_guard = phi1_pin.lock().unwrap();
                    phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
                }
                chip.update();
            }
            _ => panic!("Invalid phase: {}", phase),
        }

        // Wait for access time
        thread::sleep(Duration::from_nanos(510)); // Slightly more than access time

        // Release data bus from test control to allow ROM to drive it
        for i in 0..4 {
            let pin = chip.get_pin(&format!("D{}", i)).unwrap();
            let mut pin_guard = pin.lock().unwrap();
            pin_guard.set_driver(Some("TEST".to_string()), PinValue::HighZ);
        }
        chip.update();

        // PHI2 low to high: Data phase
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Read data
        let data = chip.read_data_bus();

        // PHI2 high to low: Cleanup
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        data
    }

    // Helper function for testing nibble timing
    fn test_nibble_timing(
        chip: &mut Intel4001,
        sync_pin: &Arc<Mutex<Pin>>,
        cm_pin: &Arc<Mutex<Pin>>,
        ci_pin: &Arc<Mutex<Pin>>,
        phi1_pin: &Arc<Mutex<Pin>>,
        phi2_pin: &Arc<Mutex<Pin>>,
        address: u16,
        nibble_delay_ns: u64,
    ) -> u8 {
        // Reset to known state (RESET is active LOW)
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);  // Assert reset
        }
        chip.update();
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);  // Release reset
        }
        chip.update();

        // Set control pins for memory read
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI2 is low initially
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI1 is low initially
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // PHI1 low to high: Address phase for high nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set high nibble on data bus
        chip.write_data_bus(((address >> 4) & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Latch high nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Delay between nibbles
        thread::sleep(Duration::from_nanos(nibble_delay_ns));

        // PHI1 low to high again: Address phase for low nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set low nibble on data bus
        chip.write_data_bus((address & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Latch low nibble and complete address
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Wait for access time
        thread::sleep(Duration::from_nanos(510)); // Slightly more than access time

        // Release data bus from test control to allow ROM to drive it
        for i in 0..4 {
            let pin = chip.get_pin(&format!("D{}", i)).unwrap();
            let mut pin_guard = pin.lock().unwrap();
            pin_guard.set_driver(Some("TEST".to_string()), PinValue::HighZ);
        }
        chip.update();

        // PHI2 low to high: Data phase
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Read data
        let data = chip.read_data_bus();

        // PHI2 high to low: Cleanup
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        data
    }

    // Helper function for testing address setup with I/O operations
    fn test_address_setup_with_io(
        chip: &mut Intel4001,
        sync_pin: &Arc<Mutex<Pin>>,
        cm_pin: &Arc<Mutex<Pin>>,
        ci_pin: &Arc<Mutex<Pin>>,
        phi1_pin: &Arc<Mutex<Pin>>,
        phi2_pin: &Arc<Mutex<Pin>>,
        address: u16,
        setup_time_ns: u64,
    ) -> u8 {
        // Reset to known state (RESET is active LOW)
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);  // Assert reset
        }
        chip.update();
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);  // Release reset
        }
        chip.update();

        // Set control pins for memory read
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Perform I/O operation during address setup
        chip.set_io_mode(IoMode::Output);
        chip.set_io_direction(1, IoDirection::Output).unwrap();
        chip.set_io_port(1, 0x0A).unwrap();
        chip.update();

        // Ensure PHI2 is low initially
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI1 is low initially
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // PHI1 low to high: Address phase for high nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set high nibble on data bus
        chip.write_data_bus(((address >> 4) & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Latch high nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // PHI1 low to high again: Address phase for low nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set low nibble on data bus
        chip.write_data_bus((address & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Latch low nibble and complete address
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Wait for specified setup time
        thread::sleep(Duration::from_nanos(setup_time_ns));

        // Release data bus from test control to allow ROM to drive it
        for i in 0..4 {
            let pin = chip.get_pin(&format!("D{}", i)).unwrap();
            let mut pin_guard = pin.lock().unwrap();
            pin_guard.set_driver(Some("TEST".to_string()), PinValue::HighZ);
        }
        chip.update();

        // PHI2 low to high: Data phase
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Wait for access time
        thread::sleep(Duration::from_nanos(510)); // Slightly more than access time

        // Read data
        let data = chip.read_data_bus();

        // PHI2 high to low: Cleanup
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        data
    }

    // Helper function for testing address setup with different clock periods
    fn test_address_setup_with_clock_period(
        chip: &mut Intel4001,
        sync_pin: &Arc<Mutex<Pin>>,
        cm_pin: &Arc<Mutex<Pin>>,
        ci_pin: &Arc<Mutex<Pin>>,
        phi1_pin: &Arc<Mutex<Pin>>,
        phi2_pin: &Arc<Mutex<Pin>>,
        address: u16,
        setup_time_ns: u64,
        clock_period_ns: u64,
    ) -> u8 {
        // Reset to known state (RESET is active LOW)
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);  // Assert reset
        }
        chip.update();
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);  // Release reset
        }
        chip.update();

        // Set control pins for memory read
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI2 is low initially
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI1 is low initially
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // PHI1 low to high: Address phase for high nibble with clock period consideration
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Wait for half clock period
        thread::sleep(Duration::from_nanos(clock_period_ns / 2));

        // Set high nibble on data bus
        chip.write_data_bus(((address >> 4) & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Latch high nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // PHI1 low to high again: Address phase for low nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Wait for half clock period
        thread::sleep(Duration::from_nanos(clock_period_ns / 2));

        // Set low nibble on data bus
        chip.write_data_bus((address & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Latch low nibble and complete address
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Wait for specified setup time
        thread::sleep(Duration::from_nanos(setup_time_ns));

        // Release data bus from test control to allow ROM to drive it
        for i in 0..4 {
            let pin = chip.get_pin(&format!("D{}", i)).unwrap();
            let mut pin_guard = pin.lock().unwrap();
            pin_guard.set_driver(Some("TEST".to_string()), PinValue::HighZ);
        }
        chip.update();

        // PHI2 low to high: Data phase
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Wait for access time
        thread::sleep(Duration::from_nanos(510)); // Slightly more than access time

        // Read data
        let data = chip.read_data_bus();

        // PHI2 high to low: Cleanup
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        data
    }

    #[test]
    fn test_clock_edge_relationships() {
        // Test proper timing relationships between clock edges with comprehensive edge cases
        let mut chip = Intel4001::new_with_access_time("CLOCK_EDGE_ROM".to_string(), 400); // Medium access time
        chip.base.set_running(true);

        // Get pin references
        let sync_pin = chip.get_pin("SYNC").unwrap();
        let cm_pin = chip.get_pin("CM").unwrap();
        let ci_pin = chip.get_pin("CI").unwrap();
        let reset_pin = chip.get_pin("RESET").unwrap();
        let phi1_pin = chip.get_pin("PHI1").unwrap();
        let phi2_pin = chip.get_pin("PHI2").unwrap();
        let d0_pin = chip.get_pin("D0").unwrap();
        let d1_pin = chip.get_pin("D1").unwrap();
        let d2_pin = chip.get_pin("D2").unwrap();
        let d3_pin = chip.get_pin("D3").unwrap();

        // Set settlement time to 0 for immediate testing
        sync_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        cm_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        ci_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        reset_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        phi1_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        phi2_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        d0_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        d1_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        d2_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        d3_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));

        // Test memory read with focus on clock edge relationships
        // Note: Intel 4004 has a 4-bit data bus, so we can only read 4 bits at a time
        let address = 0x45;
        let expected_data = 0x07; // 4-bit value (low nibble only)

        // Set up ROM data
        chip.load_rom_data(vec![expected_data], address).unwrap();

        // Test memory read using the helper function
        test_memory_read(
            &mut chip,
            &sync_pin,
            &cm_pin,
            &ci_pin,
            &phi1_pin,
            &phi2_pin,
            &d0_pin,
            &d1_pin,
            &d2_pin,
            &d3_pin,
            address as u8,
            expected_data,
        );

        // Test multiple clock edge scenarios
        for test_addr in 0x40..0x45 {
            let test_data = vec![test_addr as u8 * 3];
            chip.load_rom_data(test_data, test_addr).unwrap();
            test_memory_read(
                &mut chip,
                &sync_pin,
                &cm_pin,
                &ci_pin,
                &phi1_pin,
                &phi2_pin,
                &d0_pin,
                &d1_pin,
                &d2_pin,
                &d3_pin,
                test_addr as u8,
                test_addr as u8 * 3,
            );
        }

        // Enhanced edge case testing for clock edge relationships

        // Test edge case: PHI1 and PHI2 non-overlapping operation
        // Verify that PHI1 and PHI2 never overlap (both high at the same time)
        let non_overlap_addresses = [0x10, 0x20, 0x30, 0x40];
        for &test_addr in &non_overlap_addresses {
            chip.load_rom_data(vec![test_addr as u8], test_addr)
                .unwrap();

            let result = test_phi1_phi2_non_overlapping(
                &mut chip,
                &sync_pin,
                &cm_pin,
                &ci_pin,
                &phi1_pin,
                &phi2_pin,
                test_addr as u16,
            );
            assert_eq!(
                result, test_addr as u8,
                "Failed PHI1/PHI2 non-overlapping test at address {}",
                test_addr
            );
        }

        // Test edge case: PHI1 leading edge timing
        // Test address latching on PHI1 rising edge
        let leading_edge_addresses = [0x11, 0x21, 0x31, 0x41];
        for &test_addr in &leading_edge_addresses {
            chip.load_rom_data(vec![test_addr as u8], test_addr)
                .unwrap();

            let result = test_phi1_leading_edge(
                &mut chip,
                &sync_pin,
                &cm_pin,
                &ci_pin,
                &phi1_pin,
                &phi2_pin,
                test_addr as u16,
            );
            assert_eq!(
                result, test_addr as u8,
                "Failed PHI1 leading edge test at address {}",
                test_addr
            );
        }

        // Test edge case: PHI2 trailing edge timing
        // Test data valid on PHI2 falling edge
        let trailing_edge_addresses = [0x12, 0x22, 0x32, 0x42];
        for &test_addr in &trailing_edge_addresses {
            chip.load_rom_data(vec![test_addr as u8], test_addr)
                .unwrap();

            let result = test_phi2_trailing_edge(
                &mut chip,
                &sync_pin,
                &cm_pin,
                &ci_pin,
                &phi1_pin,
                &phi2_pin,
                test_addr as u16,
            );
            assert_eq!(
                result, test_addr as u8,
                "Failed PHI2 trailing edge test at address {}",
                test_addr
            );
        }

        // Test edge case: clock edge spacing
        // Test minimum and maximum spacing between clock edges
        let spacing_addresses = [0x13, 0x23, 0x33, 0x43];
        for &test_addr in &spacing_addresses {
            chip.load_rom_data(vec![test_addr as u8], test_addr)
                .unwrap();

            // Test minimum spacing
            let result1 = test_clock_edge_spacing(
                &mut chip,
                &sync_pin,
                &cm_pin,
                &ci_pin,
                &phi1_pin,
                &phi2_pin,
                test_addr as u16,
                50,
            ); // 50ns spacing
            assert_eq!(
                result1, test_addr as u8,
                "Failed minimum clock edge spacing test at address {}",
                test_addr
            );

            // Test maximum spacing
            let result2 = test_clock_edge_spacing(
                &mut chip,
                &sync_pin,
                &cm_pin,
                &ci_pin,
                &phi1_pin,
                &phi2_pin,
                test_addr as u16,
                1000,
            ); // 1000ns spacing
            assert_eq!(
                result2, test_addr as u8,
                "Failed maximum clock edge spacing test at address {}",
                test_addr
            );
        }

        // Test edge case: clock edge jitter
        // Test behavior with clock edge timing variations
        let jitter_addresses = [0x14, 0x24, 0x34, 0x44];
        for &test_addr in &jitter_addresses {
            chip.load_rom_data(vec![test_addr as u8], test_addr)
                .unwrap();

            // Test with positive jitter
            let result1 = test_clock_edge_jitter(
                &mut chip,
                &sync_pin,
                &cm_pin,
                &ci_pin,
                &phi1_pin,
                &phi2_pin,
                test_addr as u16,
                20,
            ); // 20ns positive jitter
            assert_eq!(
                result1, test_addr as u8,
                "Failed positive jitter test at address {}",
                test_addr
            );

            // Test with negative jitter
            let result2 = test_clock_edge_jitter(
                &mut chip,
                &sync_pin,
                &cm_pin,
                &ci_pin,
                &phi1_pin,
                &phi2_pin,
                test_addr as u16,
                -20,
            ); // 20ns negative jitter
            assert_eq!(
                result2, test_addr as u8,
                "Failed negative jitter test at address {}",
                test_addr
            );
        }

        // Test edge case: clock edge violations
        // Test what happens when clock edges occur too close together
        let mut violation_chip = Intel4001::new_with_access_time("VIOLATION_CHIP".to_string(), 400);
        violation_chip.base.set_running(true);
        violation_chip.load_rom_data(vec![0x99], 0x50).unwrap();

        let violation_sync = violation_chip.get_pin("SYNC").unwrap();
        let violation_cm = violation_chip.get_pin("CM").unwrap();
        let violation_ci = violation_chip.get_pin("CI").unwrap();
        let violation_phi1 = violation_chip.get_pin("PHI1").unwrap();
        let violation_phi2 = violation_chip.get_pin("PHI2").unwrap();

        // Set settlement times to 0
        violation_sync
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        violation_cm
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        violation_ci
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        violation_phi1
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        violation_phi2
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));

        // Test clock edge violation
        let result = test_clock_edge_violation(
            &mut violation_chip,
            &violation_sync,
            &violation_cm,
            &violation_ci,
            &violation_phi1,
            &violation_phi2,
            0x50,
            10,
        ); // 10ns spacing (violation)
           // The chip might still work due to implementation tolerances, but this tests the edge case
        println!("Clock edge violation test result: 0x{:02x}", result);

        // Test edge case: clock edge sequences
        // Test different sequences of clock edges
        let sequence_addresses = [0x15, 0x25, 0x35, 0x45];
        for &test_addr in &sequence_addresses {
            chip.load_rom_data(vec![test_addr as u8], test_addr)
                .unwrap();

            // Test normal sequence: PHI1 high -> PHI1 low -> PHI2 high -> PHI2 low
            let result1 = test_clock_edge_sequence(
                &mut chip,
                &sync_pin,
                &cm_pin,
                &ci_pin,
                &phi1_pin,
                &phi2_pin,
                test_addr as u16,
                "NORMAL",
            );
            assert_eq!(
                result1, test_addr as u8,
                "Failed normal clock edge sequence test at address {}",
                test_addr
            );

            // Test reversed sequence: PHI2 high -> PHI2 low -> PHI1 high -> PHI1 low
            let result2 = test_clock_edge_sequence(
                &mut chip,
                &sync_pin,
                &cm_pin,
                &ci_pin,
                &phi1_pin,
                &phi2_pin,
                test_addr as u16,
                "REVERSED",
            );
            // This might not work correctly, but tests the edge case
            println!(
                "Reversed clock edge sequence test result at address {}: 0x{:02x}",
                test_addr, result2
            );

            // Test simultaneous sequence: PHI1 and PHI2 high at same time
            let result3 = test_clock_edge_sequence(
                &mut chip,
                &sync_pin,
                &cm_pin,
                &ci_pin,
                &phi1_pin,
                &phi2_pin,
                test_addr as u16,
                "SIMULTANEOUS",
            );
            // This should not work correctly, but tests the edge case
            println!(
                "Simultaneous clock edge sequence test result at address {}: 0x{:02x}",
                test_addr, result3
            );
        }

        // Test edge case: clock edge duty cycle
        // Test different duty cycles for PHI1 and PHI2
        let duty_cycle_addresses = [0x16, 0x26, 0x36, 0x46];
        for &test_addr in &duty_cycle_addresses {
            chip.load_rom_data(vec![test_addr as u8], test_addr)
                .unwrap();

            // Test 25% duty cycle
            let result1 = test_clock_edge_duty_cycle(
                &mut chip,
                &sync_pin,
                &cm_pin,
                &ci_pin,
                &phi1_pin,
                &phi2_pin,
                test_addr as u16,
                25,
            );
            assert_eq!(
                result1, test_addr as u8,
                "Failed 25% duty cycle test at address {}",
                test_addr
            );

            // Test 50% duty cycle
            let result2 = test_clock_edge_duty_cycle(
                &mut chip,
                &sync_pin,
                &cm_pin,
                &ci_pin,
                &phi1_pin,
                &phi2_pin,
                test_addr as u16,
                50,
            );
            assert_eq!(
                result2, test_addr as u8,
                "Failed 50% duty cycle test at address {}",
                test_addr
            );

            // Test 75% duty cycle
            let result3 = test_clock_edge_duty_cycle(
                &mut chip,
                &sync_pin,
                &cm_pin,
                &ci_pin,
                &phi1_pin,
                &phi2_pin,
                test_addr as u16,
                75,
            );
            assert_eq!(
                result3, test_addr as u8,
                "Failed 75% duty cycle test at address {}",
                test_addr
            );
        }

        // Test edge case: clock edge frequency
        // Test different clock frequencies
        let frequency_addresses = [0x17, 0x27, 0x37, 0x47];
        let frequencies = [1000, 2000, 5000, 10000]; // Hz (periods: 1ms, 0.5ms, 0.2ms, 0.1ms)
        for (i, &test_addr) in frequency_addresses.iter().enumerate() {
            chip.load_rom_data(vec![test_addr as u8], (test_addr as u16).into())
                .unwrap();

            let result = test_clock_edge_frequency(
                &mut chip,
                &sync_pin,
                &cm_pin,
                &ci_pin,
                &phi1_pin,
                &phi2_pin,
                test_addr as u16,
                frequencies[i],
            );
            assert_eq!(
                result, test_addr as u8,
                "Failed clock frequency test at address {} with frequency {}Hz",
                test_addr, frequencies[i]
            );
        }
    }

    // Helper function for testing PHI1/PHI2 non-overlapping operation
    fn test_phi1_phi2_non_overlapping(
        chip: &mut Intel4001,
        sync_pin: &Arc<Mutex<Pin>>,
        cm_pin: &Arc<Mutex<Pin>>,
        ci_pin: &Arc<Mutex<Pin>>,
        phi1_pin: &Arc<Mutex<Pin>>,
        phi2_pin: &Arc<Mutex<Pin>>,
        address: u16,
    ) -> u8 {
        // Reset to known state (RESET is active LOW)
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);  // Assert reset
        }
        chip.update();
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);  // Release reset
        }
        chip.update();

        // Set control pins for memory read
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI2 is low initially
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI1 is low initially
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // PHI1 low to high: Address phase for high nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Verify PHI2 is still low
        assert_eq!(phi2_pin.lock().unwrap().read(), PinValue::Low);

        // Set high nibble on data bus
        chip.write_data_bus(((address >> 4) & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Latch high nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // PHI1 low to high again: Address phase for low nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set low nibble on data bus
        chip.write_data_bus((address & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Latch low nibble and complete address
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Wait for access time
        thread::sleep(Duration::from_nanos(410)); // Slightly more than access time

        // Release data bus from test control to allow ROM to drive it
        for i in 0..4 {
            let pin = chip.get_pin(&format!("D{}", i)).unwrap();
            let mut pin_guard = pin.lock().unwrap();
            pin_guard.set_driver(Some("TEST".to_string()), PinValue::HighZ);
        }
        chip.update();

        // PHI2 low to high: Data phase
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Verify PHI1 is still low
        assert_eq!(phi1_pin.lock().unwrap().read(), PinValue::Low);

        // Read data
        let data = chip.read_data_bus();

        // PHI2 high to low: Cleanup
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        data
    }

    // Helper function for testing PHI1 leading edge timing
    fn test_phi1_leading_edge(
        chip: &mut Intel4001,
        sync_pin: &Arc<Mutex<Pin>>,
        cm_pin: &Arc<Mutex<Pin>>,
        ci_pin: &Arc<Mutex<Pin>>,
        phi1_pin: &Arc<Mutex<Pin>>,
        phi2_pin: &Arc<Mutex<Pin>>,
        address: u16,
    ) -> u8 {
        // Reset to known state (RESET is active LOW)
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);  // Assert reset
        }
        chip.update();
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);  // Release reset
        }
        chip.update();

        // Set control pins for memory read
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI2 is low initially
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI1 is low initially
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Verify state is Idle before PHI1 rising edge
        assert_eq!(chip.get_timing_state(), TimingState::Idle);

        // PHI1 low to high: Address phase for high nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Verify state is AddressPhase after PHI1 rising edge
        assert_eq!(chip.get_timing_state(), TimingState::AddressPhase);

        // Set high nibble on data bus
        chip.write_data_bus(((address >> 4) & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Latch high nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // PHI1 low to high again: Address phase for low nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set low nibble on data bus
        chip.write_data_bus((address & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Latch low nibble and complete address
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Wait for access time
        thread::sleep(Duration::from_nanos(410)); // Slightly more than access time

        // Release data bus from test control to allow ROM to drive it
        for i in 0..4 {
            let pin = chip.get_pin(&format!("D{}", i)).unwrap();
            let mut pin_guard = pin.lock().unwrap();
            pin_guard.set_driver(Some("TEST".to_string()), PinValue::HighZ);
        }
        chip.update();

        // PHI2 low to high: Data phase
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Read data
        let data = chip.read_data_bus();

        // PHI2 high to low: Cleanup
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        data
    }

    // Helper function for testing PHI2 trailing edge timing
    fn test_phi2_trailing_edge(
        chip: &mut Intel4001,
        sync_pin: &Arc<Mutex<Pin>>,
        cm_pin: &Arc<Mutex<Pin>>,
        ci_pin: &Arc<Mutex<Pin>>,
        phi1_pin: &Arc<Mutex<Pin>>,
        phi2_pin: &Arc<Mutex<Pin>>,
        address: u16,
    ) -> u8 {
        // Reset to known state (RESET is active LOW)
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);  // Assert reset
        }
        chip.update();
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);  // Release reset
        }
        chip.update();

        // Set control pins for memory read
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI2 is low initially
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI1 is low initially
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // PHI1 low to high: Address phase for high nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set high nibble on data bus
        chip.write_data_bus(((address >> 4) & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Latch high nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // PHI1 low to high again: Address phase for low nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set low nibble on data bus
        chip.write_data_bus((address & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Latch low nibble and complete address
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Wait for access time
        thread::sleep(Duration::from_nanos(410)); // Slightly more than access time

        // Release data bus from test control to allow ROM to drive it
        for i in 0..4 {
            let pin = chip.get_pin(&format!("D{}", i)).unwrap();
            let mut pin_guard = pin.lock().unwrap();
            pin_guard.set_driver(Some("TEST".to_string()), PinValue::HighZ);
        }
        chip.update();

        // PHI2 low to high: Data phase
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Verify state is DriveData after PHI2 rising edge
        assert_eq!(chip.get_timing_state(), TimingState::DriveData);

        // Read data
        let data = chip.read_data_bus();

        // PHI2 high to low: Cleanup
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Verify state is Idle after PHI2 falling edge
        assert_eq!(chip.get_timing_state(), TimingState::Idle);

        data
    }

    // Helper function for testing clock edge spacing
    fn test_clock_edge_spacing(
        chip: &mut Intel4001,
        sync_pin: &Arc<Mutex<Pin>>,
        cm_pin: &Arc<Mutex<Pin>>,
        ci_pin: &Arc<Mutex<Pin>>,
        phi1_pin: &Arc<Mutex<Pin>>,
        phi2_pin: &Arc<Mutex<Pin>>,
        address: u16,
        spacing_ns: u64,
    ) -> u8 {
        // Reset to known state (RESET is active LOW)
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);  // Assert reset
        }
        chip.update();
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);  // Release reset
        }
        chip.update();

        // Set control pins for memory read
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI2 is low initially
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI1 is low initially
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // PHI1 low to high: Address phase for high nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set high nibble on data bus
        chip.write_data_bus(((address >> 4) & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Latch high nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // PHI1 low to high again: Address phase for low nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set low nibble on data bus
        chip.write_data_bus((address & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Latch low nibble and complete address
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Wait for specified spacing between PHI1 falling and PHI2 rising
        thread::sleep(Duration::from_nanos(spacing_ns));

        // Release data bus from test control to allow ROM to drive it
        for i in 0..4 {
            let pin = chip.get_pin(&format!("D{}", i)).unwrap();
            let mut pin_guard = pin.lock().unwrap();
            pin_guard.set_driver(Some("TEST".to_string()), PinValue::HighZ);
        }
        chip.update();

        // PHI2 low to high: Data phase
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Read data
        let data = chip.read_data_bus();

        // PHI2 high to low: Cleanup
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        data
    }

    // Helper function for testing clock edge jitter
    fn test_clock_edge_jitter(
        chip: &mut Intel4001,
        sync_pin: &Arc<Mutex<Pin>>,
        cm_pin: &Arc<Mutex<Pin>>,
        ci_pin: &Arc<Mutex<Pin>>,
        phi1_pin: &Arc<Mutex<Pin>>,
        phi2_pin: &Arc<Mutex<Pin>>,
        address: u16,
        jitter_ns: i64,
    ) -> u8 {
        // Reset to known state (RESET is active LOW)
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);  // Assert reset
        }
        chip.update();
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);  // Release reset
        }
        chip.update();

        // Set control pins for memory read
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI2 is low initially
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI1 is low initially
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // PHI1 low to high: Address phase for high nibble with jitter
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }

        // Apply jitter (positive or negative)
        if jitter_ns > 0 {
            thread::sleep(Duration::from_nanos(jitter_ns as u64));
        }

        chip.update();

        // Set high nibble on data bus
        chip.write_data_bus(((address >> 4) & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Latch high nibble with jitter
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }

        // Apply jitter (positive or negative)
        if jitter_ns > 0 {
            thread::sleep(Duration::from_nanos(jitter_ns as u64));
        }

        chip.update();

        // PHI1 low to high again: Address phase for low nibble with jitter
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }

        // Apply jitter (positive or negative)
        if jitter_ns > 0 {
            thread::sleep(Duration::from_nanos(jitter_ns as u64));
        }

        chip.update();

        // Set low nibble on data bus
        chip.write_data_bus((address & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Latch low nibble and complete address with jitter
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }

        // Apply jitter (positive or negative)
        if jitter_ns > 0 {
            thread::sleep(Duration::from_nanos(jitter_ns as u64));
        }

        chip.update();

        // Wait for access time
        thread::sleep(Duration::from_nanos(410)); // Slightly more than access time

        // Release data bus from test control to allow ROM to drive it
        for i in 0..4 {
            let pin = chip.get_pin(&format!("D{}", i)).unwrap();
            let mut pin_guard = pin.lock().unwrap();
            pin_guard.set_driver(Some("TEST".to_string()), PinValue::HighZ);
        }
        chip.update();

        // PHI2 low to high: Data phase with jitter
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }

        // Apply jitter (positive or negative)
        if jitter_ns > 0 {
            thread::sleep(Duration::from_nanos(jitter_ns as u64));
        }

        chip.update();

        // Read data
        let data = chip.read_data_bus();

        // PHI2 high to low: Cleanup with jitter
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }

        // Apply jitter (positive or negative)
        if jitter_ns > 0 {
            thread::sleep(Duration::from_nanos(jitter_ns as u64));
        }

        chip.update();

        data
    }

    // Helper function for testing clock edge violations
    fn test_clock_edge_violation(
        chip: &mut Intel4001,
        sync_pin: &Arc<Mutex<Pin>>,
        cm_pin: &Arc<Mutex<Pin>>,
        ci_pin: &Arc<Mutex<Pin>>,
        phi1_pin: &Arc<Mutex<Pin>>,
        phi2_pin: &Arc<Mutex<Pin>>,
        address: u16,
        spacing_ns: u64,
    ) -> u8 {
        // Reset to known state (RESET is active LOW)
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);  // Assert reset
        }
        chip.update();
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);  // Release reset
        }
        chip.update();

        // Set control pins for memory read
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI2 is low initially
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI1 is low initially
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // PHI1 low to high: Address phase for high nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set high nibble on data bus
        chip.write_data_bus(((address >> 4) & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Latch high nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // PHI1 low to high again: Address phase for low nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set low nibble on data bus
        chip.write_data_bus((address & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Latch low nibble and complete address
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Wait for very short spacing (violation)
        thread::sleep(Duration::from_nanos(spacing_ns));

        // Release data bus from test control to allow ROM to drive it
        for i in 0..4 {
            let pin = chip.get_pin(&format!("D{}", i)).unwrap();
            let mut pin_guard = pin.lock().unwrap();
            pin_guard.set_driver(Some("TEST".to_string()), PinValue::HighZ);
        }
        chip.update();

        // PHI2 low to high: Data phase
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Read data
        let data = chip.read_data_bus();

        // PHI2 high to low: Cleanup
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        data
    }

    // Helper function for testing clock edge sequences
    fn test_clock_edge_sequence(
        chip: &mut Intel4001,
        sync_pin: &Arc<Mutex<Pin>>,
        cm_pin: &Arc<Mutex<Pin>>,
        ci_pin: &Arc<Mutex<Pin>>,
        phi1_pin: &Arc<Mutex<Pin>>,
        phi2_pin: &Arc<Mutex<Pin>>,
        address: u16,
        sequence: &str,
    ) -> u8 {
        // Reset to known state (RESET is active LOW)
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);  // Assert reset (active LOW)
        }
        chip.update();
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);  // Release reset (HIGH = normal operation)
        }
        chip.update();

        // Set control pins for memory read
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI2 is low initially
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI1 is low initially
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        match sequence {
            "NORMAL" => {
                // Normal sequence: PHI1 high -> PHI1 low -> PHI1 high -> PHI1 low (two cycles for address) -> PHI2 high -> PHI2 low
                // PHI1 low to high: Address phase for high nibble
                {
                    let mut phi1_guard = phi1_pin.lock().unwrap();
                    phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
                }
                chip.update();

                // Set high nibble on data bus
                chip.write_data_bus(((address >> 4) & 0x0F) as u8);
                chip.update();

                // PHI1 high to low: Latch high nibble
                {
                    let mut phi1_guard = phi1_pin.lock().unwrap();
                    phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
                }
                chip.update();

                // PHI1 low to high again: Address phase for low nibble
                {
                    let mut phi1_guard = phi1_pin.lock().unwrap();
                    phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
                }
                chip.update();

                // Set low nibble on data bus
                chip.write_data_bus((address & 0x0F) as u8);
                chip.update();

                // PHI1 high to low: Latch low nibble and complete address
                {
                    let mut phi1_guard = phi1_pin.lock().unwrap();
                    phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
                }
                chip.update();

                thread::sleep(Duration::from_nanos(410));

                // Release data bus from test control to allow ROM to drive it
                for i in 0..4 {
                    let pin = chip.get_pin(&format!("D{}", i)).unwrap();
                    let mut pin_guard = pin.lock().unwrap();
                    pin_guard.set_driver(Some("TEST".to_string()), PinValue::HighZ);
                }
                chip.update();

                {
                    let mut phi2_guard = phi2_pin.lock().unwrap();
                    phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
                }
                chip.update();

                let data = chip.read_data_bus();

                {
                    let mut phi2_guard = phi2_pin.lock().unwrap();
                    phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
                }
                chip.update();

                return data;
            }
            "REVERSED" => {
                // Reversed sequence: PHI2 high -> PHI2 low -> PHI1 high -> PHI1 low
                // This is an invalid sequence for the Intel 4004
                {
                    let mut phi2_guard = phi2_pin.lock().unwrap();
                    phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
                }
                chip.update();

                {
                    let mut phi2_guard = phi2_pin.lock().unwrap();
                    phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
                }
                chip.update();

                // PHI1 low to high: Address phase for high nibble
                {
                    let mut phi1_guard = phi1_pin.lock().unwrap();
                    phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
                }
                chip.update();

                // Set high nibble on data bus
                chip.write_data_bus(((address >> 4) & 0x0F) as u8);
                chip.update();

                // PHI1 high to low: Latch high nibble
                {
                    let mut phi1_guard = phi1_pin.lock().unwrap();
                    phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
                }
                chip.update();

                // PHI1 low to high again: Address phase for low nibble
                {
                    let mut phi1_guard = phi1_pin.lock().unwrap();
                    phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
                }
                chip.update();

                // Set low nibble on data bus
                chip.write_data_bus((address & 0x0F) as u8);
                chip.update();

                // PHI1 high to low: Latch low nibble and complete address
                {
                    let mut phi1_guard = phi1_pin.lock().unwrap();
                    phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
                }
                chip.update();

                thread::sleep(Duration::from_nanos(410));

                // Release data bus from test control to allow ROM to drive it
                for i in 0..4 {
                    let pin = chip.get_pin(&format!("D{}", i)).unwrap();
                    let mut pin_guard = pin.lock().unwrap();
                    pin_guard.set_driver(Some("TEST".to_string()), PinValue::HighZ);
                }
                chip.update();

                return chip.read_data_bus();
            }
            "SIMULTANEOUS" => {
                // Simultaneous sequence: PHI1 and PHI2 high at same time
                // This is an invalid sequence for the Intel 4004 (non-overlapping clocks required)
                {
                    let mut phi1_guard = phi1_pin.lock().unwrap();
                    phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
                    let mut phi2_guard = phi2_pin.lock().unwrap();
                    phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
                }
                chip.update();

                // Set high nibble on data bus
                chip.write_data_bus(((address >> 4) & 0x0F) as u8);
                chip.update();

                // PHI1 high to low: Latch high nibble
                {
                    let mut phi1_guard = phi1_pin.lock().unwrap();
                    phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
                }
                chip.update();

                // PHI1 low to high again: Address phase for low nibble
                {
                    let mut phi1_guard = phi1_pin.lock().unwrap();
                    phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
                }
                chip.update();

                // Set low nibble on data bus
                chip.write_data_bus((address & 0x0F) as u8);
                chip.update();

                // PHI1 high to low: Latch low nibble and complete address
                {
                    let mut phi1_guard = phi1_pin.lock().unwrap();
                    phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
                    let mut phi2_guard = phi2_pin.lock().unwrap();
                    phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
                }
                chip.update();

                thread::sleep(Duration::from_nanos(410));

                // Release data bus from test control to allow ROM to drive it
                for i in 0..4 {
                    let pin = chip.get_pin(&format!("D{}", i)).unwrap();
                    let mut pin_guard = pin.lock().unwrap();
                    pin_guard.set_driver(Some("TEST".to_string()), PinValue::HighZ);
                }
                chip.update();

                return chip.read_data_bus();
            }
            _ => panic!("Invalid sequence: {}", sequence),
        }
    }

    // Helper function for testing clock edge duty cycle
    fn test_clock_edge_duty_cycle(
        chip: &mut Intel4001,
        sync_pin: &Arc<Mutex<Pin>>,
        cm_pin: &Arc<Mutex<Pin>>,
        ci_pin: &Arc<Mutex<Pin>>,
        phi1_pin: &Arc<Mutex<Pin>>,
        phi2_pin: &Arc<Mutex<Pin>>,
        address: u16,
        duty_cycle_percent: u8,
    ) -> u8 {
        // Reset to known state (RESET is active LOW)
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);  // Assert reset (active LOW)
        }
        chip.update();
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);  // Release reset (HIGH = normal operation)
        }
        chip.update();

        // Set control pins for memory read
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI2 is low initially
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI1 is low initially
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Calculate timing based on duty cycle
        let total_period_ns = 1000; // 1kHz clock
        let high_time_ns = (total_period_ns * duty_cycle_percent as u64) / 100;

        // PHI1 low to high: Address phase for high nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Wait for high time
        thread::sleep(Duration::from_nanos(high_time_ns));

        // Set high nibble on data bus
        chip.write_data_bus(((address >> 4) & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Latch high nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // PHI1 low to high again: Address phase for low nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Wait for high time
        thread::sleep(Duration::from_nanos(high_time_ns));

        // Set low nibble on data bus
        chip.write_data_bus((address & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Latch low nibble and complete address
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Wait for access time
        thread::sleep(Duration::from_nanos(410));

        // Release data bus from test control to allow ROM to drive it
        for i in 0..4 {
            let pin = chip.get_pin(&format!("D{}", i)).unwrap();
            let mut pin_guard = pin.lock().unwrap();
            pin_guard.set_driver(Some("TEST".to_string()), PinValue::HighZ);
        }
        chip.update();

        // PHI2 low to high: Data phase
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Wait for high time
        thread::sleep(Duration::from_nanos(high_time_ns));

        // Read data
        let data = chip.read_data_bus();

        // PHI2 high to low: Cleanup
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        data
    }

    // Helper function for testing clock edge frequency
    fn test_clock_edge_frequency(
        chip: &mut Intel4001,
        sync_pin: &Arc<Mutex<Pin>>,
        cm_pin: &Arc<Mutex<Pin>>,
        ci_pin: &Arc<Mutex<Pin>>,
        phi1_pin: &Arc<Mutex<Pin>>,
        phi2_pin: &Arc<Mutex<Pin>>,
        address: u16,
        frequency_hz: u64,
    ) -> u8 {
        // Reset to known state (RESET is active LOW)
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);  // Assert reset (active LOW)
        }
        chip.update();
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);  // Release reset (HIGH = normal operation)
        }
        chip.update();

        // Set control pins for memory read
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }

        // Ensure PHI2 is low initially
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI1 is low initially
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Calculate timing based on frequency
        let period_ns = 1_000_000_000 / frequency_hz; // Convert Hz to nanoseconds
        let half_period_ns = period_ns / 2;

        // PHI1 low to high: Address phase for high nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Wait for half period
        thread::sleep(Duration::from_nanos(half_period_ns));

        // Set high nibble on data bus
        chip.write_data_bus(((address >> 4) & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Latch high nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // PHI1 low to high again: Address phase for low nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Wait for half period
        thread::sleep(Duration::from_nanos(half_period_ns));

        // Set low nibble on data bus
        chip.write_data_bus((address & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Latch low nibble and complete address
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Wait for access time
        thread::sleep(Duration::from_nanos(410));

        // Release data bus from test control to allow ROM to drive it
        for i in 0..4 {
            let pin = chip.get_pin(&format!("D{}", i)).unwrap();
            let mut pin_guard = pin.lock().unwrap();
            pin_guard.set_driver(Some("TEST".to_string()), PinValue::HighZ);
        }
        chip.update();

        // PHI2 low to high: Data phase
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Wait for half period
        thread::sleep(Duration::from_nanos(half_period_ns));

        // Read data
        let data = chip.read_data_bus();

        // PHI2 high to low: Cleanup
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        data
    }

    // Helper function for testing access time tolerance
    fn test_access_time_tolerance(chip: &mut Intel4001, address: u16, _expected_data: u8) -> u8 {
        // Reset to known state (RESET is active LOW)
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);  // Assert reset (active LOW)
        }
        chip.update();
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);  // Release reset (HIGH = normal operation)
        }
        chip.update();

        // Get pins
        let sync_pin = chip.get_pin("SYNC").unwrap();
        let cm_pin = chip.get_pin("CM").unwrap();
        let ci_pin = chip.get_pin("CI").unwrap();
        let phi1_pin = chip.get_pin("PHI1").unwrap();
        let phi2_pin = chip.get_pin("PHI2").unwrap();

        // Set control pins for memory read
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }

        // Ensure PHI2 is low initially
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Ensure PHI1 is low initially
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // PHI1 low to high: Address phase for high nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set high nibble on data bus
        chip.write_data_bus(((address >> 4) & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Latch high nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // PHI1 low to high again: Address phase for low nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set low nibble on data bus
        chip.write_data_bus((address & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Latch low nibble and complete address
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Wait for access time with tolerance
        let access_time = chip.get_access_time();
        thread::sleep(Duration::from_nanos(access_time + 50)); // Add 50ns tolerance

        // Release data bus from test control to allow ROM to drive it
        for i in 0..4 {
            let pin = chip.get_pin(&format!("D{}", i)).unwrap();
            let mut pin_guard = pin.lock().unwrap();
            pin_guard.set_driver(Some("TEST".to_string()), PinValue::HighZ);
        }
        chip.update();

        // PHI2 low to high: Data phase
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Read data
        let data = chip.read_data_bus();

        // PHI2 high to low: Cleanup
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        data
    }

    // Helper function for testing memory read tolerance
    fn test_memory_read_tolerance(
        chip: &mut Intel4001,
        sync_pin: &Arc<Mutex<Pin>>,
        cm_pin: &Arc<Mutex<Pin>>,
        ci_pin: &Arc<Mutex<Pin>>,
        phi1_pin: &Arc<Mutex<Pin>>,
        phi2_pin: &Arc<Mutex<Pin>>,
        address: u16,
        _expected_data: u8,
        timing_variation_ns: u64,
    ) -> u8 {
        // Reset to known state (RESET is active LOW)
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);  // Assert reset (active LOW)
        }
        chip.update();
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);  // Release reset (HIGH = normal operation)
        }
        chip.update();

        // Set control pins for memory read
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }

        // PHI1 low to high: Address phase with timing variation
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        thread::sleep(Duration::from_nanos(timing_variation_ns)); // Add timing variation
        chip.update();

        // Set high nibble
        chip.write_data_bus(((address >> 4) & 0x0F) as u8);
        chip.update();

        // Set low nibble
        chip.write_data_bus((address & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Complete address phase with timing variation
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        thread::sleep(Duration::from_nanos(timing_variation_ns)); // Add timing variation
        chip.update();

        // Wait for access time
        thread::sleep(Duration::from_nanos(510)); // Slightly more than access time

        // PHI2 low to high: Data phase with timing variation
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        thread::sleep(Duration::from_nanos(timing_variation_ns)); // Add timing variation
        chip.update();

        // Read data
        let data = chip.read_data_bus();

        // PHI2 high to low: Cleanup with timing variation
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        thread::sleep(Duration::from_nanos(timing_variation_ns)); // Add timing variation
        chip.update();

        data
    }

    // Helper function for testing timing variation tolerance
    fn test_timing_variation_tolerance(
        chip: &mut Intel4001,
        sync_pin: &Arc<Mutex<Pin>>,
        cm_pin: &Arc<Mutex<Pin>>,
        ci_pin: &Arc<Mutex<Pin>>,
        phi1_pin: &Arc<Mutex<Pin>>,
        phi2_pin: &Arc<Mutex<Pin>>,
        address: u16,
        _expected_data: u8,
        variation_ns: u64,
    ) -> u8 {
        // Reset to known state
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Set control pins for memory read
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }

        // PHI1 low to high: Address phase with variation
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set high nibble with variation
        chip.write_data_bus(((address >> 4) & 0x0F) as u8);
        thread::sleep(Duration::from_nanos(variation_ns));
        chip.update();

        // Set low nibble with variation
        chip.write_data_bus((address & 0x0F) as u8);
        thread::sleep(Duration::from_nanos(variation_ns));
        chip.update();

        // PHI1 high to low: Complete address phase with variation
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Wait for access time with variation
        thread::sleep(Duration::from_nanos(510 + variation_ns));

        // PHI2 low to high: Data phase with variation
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Read data
        let data = chip.read_data_bus();

        // PHI2 high to low: Cleanup with variation
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        data
    }

    // Helper function for testing clock period tolerance
    fn test_clock_period_tolerance(
        chip: &mut Intel4001,
        sync_pin: &Arc<Mutex<Pin>>,
        cm_pin: &Arc<Mutex<Pin>>,
        ci_pin: &Arc<Mutex<Pin>>,
        phi1_pin: &Arc<Mutex<Pin>>,
        phi2_pin: &Arc<Mutex<Pin>>,
        address: u16,
        _expected_data: u8,
        clock_period_ns: u64,
    ) -> u8 {
        // Reset to known state
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Set control pins for memory read
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }

        // PHI1 low to high: Address phase with clock period consideration
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Wait for half clock period
        thread::sleep(Duration::from_nanos(clock_period_ns / 2));

        // Set high nibble
        chip.write_data_bus(((address >> 4) & 0x0F) as u8);
        chip.update();

        // Wait for half clock period
        thread::sleep(Duration::from_nanos(clock_period_ns / 2));

        // Set low nibble
        chip.write_data_bus((address & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Complete address phase
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Wait for clock period
        thread::sleep(Duration::from_nanos(clock_period_ns));

        // PHI2 low to high: Data phase
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Wait for half clock period
        thread::sleep(Duration::from_nanos(clock_period_ns / 2));

        // Read data
        let data = chip.read_data_bus();

        // PHI2 high to low: Cleanup
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        data
    }

    // Helper function for testing address setup tolerance
    fn test_address_setup_tolerance(
        chip: &mut Intel4001,
        sync_pin: &Arc<Mutex<Pin>>,
        cm_pin: &Arc<Mutex<Pin>>,
        ci_pin: &Arc<Mutex<Pin>>,
        phi1_pin: &Arc<Mutex<Pin>>,
        phi2_pin: &Arc<Mutex<Pin>>,
        address: u16,
        _expected_data: u8,
        setup_time_ns: u64,
    ) -> u8 {
        // Reset to known state
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Set control pins for memory read
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }

        // PHI1 low to high: Address phase
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set high nibble
        chip.write_data_bus(((address >> 4) & 0x0F) as u8);
        chip.update();

        // Set low nibble
        chip.write_data_bus((address & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Complete address phase
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Wait for specified setup time
        thread::sleep(Duration::from_nanos(setup_time_ns));

        // PHI2 low to high: Data phase
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Wait for access time
        thread::sleep(Duration::from_nanos(510)); // Slightly more than access time

        // Read data
        let data = chip.read_data_bus();

        // PHI2 high to low: Cleanup
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        data
    }

    // Helper function for testing address hold tolerance
    fn test_address_hold_tolerance(
        chip: &mut Intel4001,
        sync_pin: &Arc<Mutex<Pin>>,
        cm_pin: &Arc<Mutex<Pin>>,
        ci_pin: &Arc<Mutex<Pin>>,
        phi1_pin: &Arc<Mutex<Pin>>,
        phi2_pin: &Arc<Mutex<Pin>>,
        address: u16,
        _expected_data: u8,
        hold_time_ns: u64,
    ) -> u8 {
        // Reset to known state
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Set control pins for memory read
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }

        // PHI1 low to high: Address phase
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set high nibble
        chip.write_data_bus(((address >> 4) & 0x0F) as u8);
        chip.update();

        // Set low nibble
        chip.write_data_bus((address & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Complete address phase
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Wait for access time
        thread::sleep(Duration::from_nanos(510)); // Slightly more than access time

        // PHI2 low to high: Data phase
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Wait for specified hold time
        thread::sleep(Duration::from_nanos(hold_time_ns));

        // Read data
        let data = chip.read_data_bus();

        // PHI2 high to low: Cleanup
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        data
    }

    // Helper function for testing voltage and temperature tolerance
    fn test_voltage_temperature_tolerance(
        chip: &mut Intel4001,
        sync_pin: &Arc<Mutex<Pin>>,
        cm_pin: &Arc<Mutex<Pin>>,
        ci_pin: &Arc<Mutex<Pin>>,
        phi1_pin: &Arc<Mutex<Pin>>,
        phi2_pin: &Arc<Mutex<Pin>>,
        address: u16,
        _expected_data: u8,
        voltage: f64,
        temperature: f64,
    ) -> u8 {
        // Reset to known state
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Simulate voltage and temperature effects
        // In a real implementation, this would affect timing parameters
        // For this test, we'll just add a delay based on voltage and temperature
        let voltage_delay = if voltage < 5.0 {
            20
        } else if voltage > 5.0 {
            10
        } else {
            0
        };
        let temperature_delay = if temperature < 25.0 {
            15
        } else if temperature > 25.0 {
            25
        } else {
            0
        };
        let total_delay = voltage_delay + temperature_delay;

        // Set control pins for memory read
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }

        // PHI1 low to high: Address phase
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set high nibble
        chip.write_data_bus(((address >> 4) & 0x0F) as u8);
        chip.update();

        // Set low nibble
        chip.write_data_bus((address & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Complete address phase
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Wait for access time with voltage/temperature compensation
        thread::sleep(Duration::from_nanos(510 + total_delay));

        // PHI2 low to high: Data phase
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Read data
        let data = chip.read_data_bus();

        // PHI2 high to low: Cleanup
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        data
    }

    // Helper function for testing voltage tolerance
    fn test_voltage_tolerance(
        chip: &mut Intel4001,
        sync_pin: &Arc<Mutex<Pin>>,
        cm_pin: &Arc<Mutex<Pin>>,
        ci_pin: &Arc<Mutex<Pin>>,
        phi1_pin: &Arc<Mutex<Pin>>,
        phi2_pin: &Arc<Mutex<Pin>>,
        address: u16,
        _expected_data: u8,
        voltage: f64,
    ) -> u8 {
        // Reset to known state
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Simulate voltage effects
        // In a real implementation, this would affect timing parameters
        // For this test, we'll just add a delay based on voltage
        let voltage_delay = if voltage < 5.0 {
            20
        } else if voltage > 5.0 {
            10
        } else {
            0
        };

        // Set control pins for memory read
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }

        // PHI1 low to high: Address phase
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set high nibble
        chip.write_data_bus(((address >> 4) & 0x0F) as u8);
        chip.update();

        // Set low nibble
        chip.write_data_bus((address & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Complete address phase
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Wait for access time with voltage compensation
        thread::sleep(Duration::from_nanos(510 + voltage_delay));

        // PHI2 low to high: Data phase
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Read data
        let data = chip.read_data_bus();

        // PHI2 high to low: Cleanup
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        data
    }

    // Helper function for testing temperature tolerance
    fn test_temperature_tolerance(
        chip: &mut Intel4001,
        sync_pin: &Arc<Mutex<Pin>>,
        cm_pin: &Arc<Mutex<Pin>>,
        ci_pin: &Arc<Mutex<Pin>>,
        phi1_pin: &Arc<Mutex<Pin>>,
        phi2_pin: &Arc<Mutex<Pin>>,
        address: u16,
        _expected_data: u8,
        temperature: f64,
    ) -> u8 {
        // Reset to known state
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Simulate temperature effects
        // In a real implementation, this would affect timing parameters
        // For this test, we'll just add a delay based on temperature
        let temperature_delay = if temperature < 25.0 {
            15
        } else if temperature > 25.0 {
            25
        } else {
            0
        };

        // Set control pins for memory read
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }

        // PHI1 low to high: Address phase
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set high nibble
        chip.write_data_bus(((address >> 4) & 0x0F) as u8);
        chip.update();

        // Set low nibble
        chip.write_data_bus((address & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Complete address phase
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Wait for access time with temperature compensation
        thread::sleep(Duration::from_nanos(510 + temperature_delay));

        // PHI2 low to high: Data phase
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Read data
        let data = chip.read_data_bus();

        // PHI2 high to low: Cleanup
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        data
    }

    // Helper function for testing manufacturing tolerance
    fn test_manufacturing_tolerance(
        chip: &mut Intel4001,
        sync_pin: &Arc<Mutex<Pin>>,
        cm_pin: &Arc<Mutex<Pin>>,
        ci_pin: &Arc<Mutex<Pin>>,
        phi1_pin: &Arc<Mutex<Pin>>,
        phi2_pin: &Arc<Mutex<Pin>>,
        address: u16,
        _expected_data: u8,
        variation_percent: i32,
    ) -> u8 {
        // Reset to known state
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Simulate manufacturing variations
        // In a real implementation, this would affect timing parameters
        // For this test, we'll just add a delay based on variation
        let base_access_time = 500; // ns
        let variation = (base_access_time * variation_percent as u64) / 100;
        let adjusted_access_time = base_access_time + variation;

        // Set control pins for memory read
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }

        // PHI1 low to high: Address phase
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set high nibble
        chip.write_data_bus(((address >> 4) & 0x0F) as u8);
        chip.update();

        // Set low nibble
        chip.write_data_bus((address & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Complete address phase
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Wait for adjusted access time
        thread::sleep(Duration::from_nanos(adjusted_access_time + 10));

        // PHI2 low to high: Data phase
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Read data
        let data = chip.read_data_bus();

        // PHI2 high to low: Cleanup
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        data
    }

    // Helper function for testing manufacturing variation
    fn test_manufacturing_variation(
        chip: &mut Intel4001,
        sync_pin: &Arc<Mutex<Pin>>,
        cm_pin: &Arc<Mutex<Pin>>,
        ci_pin: &Arc<Mutex<Pin>>,
        phi1_pin: &Arc<Mutex<Pin>>,
        phi2_pin: &Arc<Mutex<Pin>>,
        address: u16,
        _expected_data: u8,
        variation_type: &str,
    ) -> u8 {
        // Reset to known state
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Simulate manufacturing variations
        // In a real implementation, this would affect timing parameters
        // For this test, we'll just add a delay based on variation type
        let variation_delay = match variation_type {
            "FAST" => -50,  // 50ns faster
            "SLOW" => 100,  // 100ns slower
            "TYPICAL" => 0, // No variation
            "MIN" => -100,  // 100ns faster (minimum)
            "MAX" => 200,   // 200ns slower (maximum)
            _ => 0,
        };

        // Set control pins for memory read
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }

        // PHI1 low to high: Address phase
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set high nibble
        chip.write_data_bus(((address >> 4) & 0x0F) as u8);
        chip.update();

        // Set low nibble
        chip.write_data_bus((address & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Complete address phase
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Wait for access time with variation
        let base_access_time = 500; // ns
        let adjusted_access_time = if variation_delay >= 0 {
            base_access_time + variation_delay as u64
        } else {
            base_access_time - (-variation_delay) as u64
        };
        thread::sleep(Duration::from_nanos(adjusted_access_time + 10));

        // PHI2 low to high: Data phase
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Read data
        let data = chip.read_data_bus();

        // PHI2 high to low: Cleanup
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        data
    }

    // Helper function for testing aging tolerance
    fn test_aging_tolerance(
        chip: &mut Intel4001,
        sync_pin: &Arc<Mutex<Pin>>,
        cm_pin: &Arc<Mutex<Pin>>,
        ci_pin: &Arc<Mutex<Pin>>,
        phi1_pin: &Arc<Mutex<Pin>>,
        phi2_pin: &Arc<Mutex<Pin>>,
        address: u16,
        _expected_data: u8,
        years: u32,
    ) -> u8 {
        // Reset to known state
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Simulate aging effects
        // In a real implementation, this would affect timing parameters
        // For this test, we'll just add a delay based on years
        let aging_delay = years * 5; // 5ns per year

        // Set control pins for memory read
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }

        // PHI1 low to high: Address phase
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set high nibble
        chip.write_data_bus(((address >> 4) & 0x0F) as u8);
        chip.update();

        // Set low nibble
        chip.write_data_bus((address & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Complete address phase
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Wait for access time with aging compensation
        thread::sleep(Duration::from_nanos((510 + aging_delay) as u64));

        // PHI2 low to high: Data phase
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Read data
        let data = chip.read_data_bus();

        // PHI2 high to low: Cleanup
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        data
    }

    // Helper function for testing aging effect
    fn test_aging_effect(
        chip: &mut Intel4001,
        sync_pin: &Arc<Mutex<Pin>>,
        cm_pin: &Arc<Mutex<Pin>>,
        ci_pin: &Arc<Mutex<Pin>>,
        phi1_pin: &Arc<Mutex<Pin>>,
        phi2_pin: &Arc<Mutex<Pin>>,
        address: u16,
        _expected_data: u8,
        aging_effect: &str,
    ) -> u8 {
        // Reset to known state
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Simulate aging effects
        // In a real implementation, this would affect timing parameters
        // For this test, we'll just add a delay based on aging effect
        let aging_delay = match aging_effect {
            "FRESH" => 0,      // No aging
            "WORN" => 50,      // 50ns slower
            "DEGRADED" => 100, // 100ns slower
            "FAILING" => 200,  // 200ns slower
            _ => 0,
        };

        // Set control pins for memory read
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }

        // PHI1 low to high: Address phase
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set high nibble
        chip.write_data_bus(((address >> 4) & 0x0F) as u8);
        chip.update();

        // Set low nibble
        chip.write_data_bus((address & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Complete address phase
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Wait for access time with aging compensation
        thread::sleep(Duration::from_nanos(510 + aging_delay));

        // PHI2 low to high: Data phase
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Read data
        let data = chip.read_data_bus();

        // PHI2 high to low: Cleanup
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        data
    }

    // Helper function for testing extreme condition tolerance
    fn test_extreme_condition_tolerance(
        chip: &mut Intel4001,
        sync_pin: &Arc<Mutex<Pin>>,
        cm_pin: &Arc<Mutex<Pin>>,
        ci_pin: &Arc<Mutex<Pin>>,
        phi1_pin: &Arc<Mutex<Pin>>,
        phi2_pin: &Arc<Mutex<Pin>>,
        address: u16,
        _expected_data: u8,
        voltage: f64,
        temperature: f64,
        aging_years: u32,
    ) -> u8 {
        // Reset to known state
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();
        {
            let reset_pin = chip.get_pin("RESET").unwrap();
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Simulate extreme condition effects
        // In a real implementation, this would affect timing parameters
        // For this test, we'll just add a delay based on conditions
        let voltage_delay = if voltage < 5.0 {
            20
        } else if voltage > 5.0 {
            10
        } else {
            0
        };
        let temperature_delay = if temperature < 25.0 {
            15
        } else if temperature > 25.0 {
            25
        } else {
            0
        };
        let aging_delay = aging_years * 5; // 5ns per year
        let total_delay = voltage_delay + temperature_delay + aging_delay;

        // Set control pins for memory read
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }

        // PHI1 low to high: Address phase
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Set high nibble
        chip.write_data_bus(((address >> 4) & 0x0F) as u8);
        chip.update();

        // Set low nibble
        chip.write_data_bus((address & 0x0F) as u8);
        chip.update();

        // PHI1 high to low: Complete address phase
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        // Wait for access time with extreme condition compensation
        thread::sleep(Duration::from_nanos((510 + total_delay) as u64));

        // PHI2 low to high: Data phase
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        chip.update();

        // Read data
        let data = chip.read_data_bus();

        // PHI2 high to low: Cleanup
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        chip.update();

        data
    }

    #[test]
    fn test_timing_tolerances() {
        // Test behavior with timing variations and tolerances with comprehensive edge cases
        let mut chip = Intel4001::new_with_access_time("TOLERANCE_ROM".to_string(), 500); // Standard access time
        chip.base.set_running(true);

        // Get pin references
        let sync_pin = chip.get_pin("SYNC").unwrap();
        let cm_pin = chip.get_pin("CM").unwrap();
        let ci_pin = chip.get_pin("CI").unwrap();
        let reset_pin = chip.get_pin("RESET").unwrap();
        let phi1_pin = chip.get_pin("PHI1").unwrap();
        let phi2_pin = chip.get_pin("PHI2").unwrap();
        let d0_pin = chip.get_pin("D0").unwrap();
        let d1_pin = chip.get_pin("D1").unwrap();
        let d2_pin = chip.get_pin("D2").unwrap();
        let d3_pin = chip.get_pin("D3").unwrap();

        // Set settlement time to 0 for immediate testing
        sync_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        cm_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        ci_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        reset_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        phi1_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        phi2_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        d0_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        d1_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        d2_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        d3_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));

        // Test memory read with various timing tolerances
        let address = 0x78;
        let expected_data = 0x0A; // 4-bit value (low nibble only)

        // Set up ROM data
        chip.load_rom_data(vec![expected_data], address).unwrap();

        // Test memory read using the helper function
        test_memory_read(
            &mut chip,
            &sync_pin,
            &cm_pin,
            &ci_pin,
            &phi1_pin,
            &phi2_pin,
            &d0_pin,
            &d1_pin,
            &d2_pin,
            &d3_pin,
            address as u8,
            expected_data,
        );

        // Test multiple timing tolerance scenarios
        for test_addr in 0x78..0x80 {
            let test_data = vec![test_addr as u8 * 2];
            chip.load_rom_data(test_data, test_addr).unwrap();
            test_memory_read(
                &mut chip,
                &sync_pin,
                &cm_pin,
                &ci_pin,
                &phi1_pin,
                &phi2_pin,
                &d0_pin,
                &d1_pin,
                &d2_pin,
                &d3_pin,
                test_addr as u8,
                test_addr as u8 * 2,
            );
        }

        // Enhanced edge case testing for timing tolerances

        // Test edge case: access time tolerance variations
        let tolerance_addresses = [0x10, 0x20, 0x30, 0x40];
        for &test_addr in &tolerance_addresses {
            chip.load_rom_data(vec![test_addr as u8], test_addr)
                .unwrap();

            let result = test_access_time_tolerance(&mut chip, test_addr as u16, test_addr as u8);
            assert_eq!(
                result, test_addr as u8,
                "Failed access time tolerance test at address {}",
                test_addr
            );
        }

        // Test edge case: memory read with timing variations
        let variation_addresses = [0x11, 0x21, 0x31, 0x41];
        for &test_addr in &variation_addresses {
            chip.load_rom_data(vec![test_addr as u8], test_addr)
                .unwrap();

            // Test with different timing variations
            for variation in [0, 10, 20, 50, 100] {
                let result = test_memory_read_tolerance(
                    &mut chip,
                    &sync_pin,
                    &cm_pin,
                    &ci_pin,
                    &phi1_pin,
                    &phi2_pin,
                    test_addr as u16,
                    test_addr as u8,
                    variation,
                );
                assert_eq!(
                    result, test_addr as u8,
                    "Failed memory read tolerance test with {}ns variation at address {}",
                    variation, test_addr
                );
            }
        }

        // Test edge case: timing variation tolerance
        let variation_test_addresses = [0x12, 0x22, 0x32, 0x42];
        for &test_addr in &variation_test_addresses {
            chip.load_rom_data(vec![test_addr as u8], test_addr)
                .unwrap();

            // Test with different timing variations
            for variation in [0, 25, 50, 75, 100] {
                let result = test_timing_variation_tolerance(
                    &mut chip,
                    &sync_pin,
                    &cm_pin,
                    &ci_pin,
                    &phi1_pin,
                    &phi2_pin,
                    test_addr as u16,
                    test_addr as u8,
                    variation,
                );
                assert_eq!(
                    result, test_addr as u8,
                    "Failed timing variation tolerance test with {}ns variation at address {}",
                    variation, test_addr
                );
            }
        }

        // Test edge case: clock period tolerance
        let clock_period_addresses = [0x13, 0x23, 0x33, 0x43];
        for &test_addr in &clock_period_addresses {
            chip.load_rom_data(vec![test_addr as u8], test_addr)
                .unwrap();

            // Test with different clock periods
            for period in [100, 200, 500, 1000] {
                let result = test_clock_period_tolerance(
                    &mut chip,
                    &sync_pin,
                    &cm_pin,
                    &ci_pin,
                    &phi1_pin,
                    &phi2_pin,
                    test_addr as u16,
                    test_addr as u8,
                    period,
                );
                assert_eq!(
                    result, test_addr as u8,
                    "Failed clock period tolerance test with {}ns period at address {}",
                    period, test_addr
                );
            }
        }

        // Test edge case: address setup tolerance
        let setup_tolerance_addresses = [0x14, 0x24, 0x34, 0x44];
        for &test_addr in &setup_tolerance_addresses {
            chip.load_rom_data(vec![test_addr as u8], test_addr)
                .unwrap();

            // Test with different setup times
            for setup_time in [50, 100, 150, 200] {
                let result = test_address_setup_tolerance(
                    &mut chip,
                    &sync_pin,
                    &cm_pin,
                    &ci_pin,
                    &phi1_pin,
                    &phi2_pin,
                    test_addr as u16,
                    test_addr as u8,
                    setup_time,
                );
                assert_eq!(
                    result, test_addr as u8,
                    "Failed address setup tolerance test with {}ns setup time at address {}",
                    setup_time, test_addr
                );
            }
        }

        // Test edge case: address hold tolerance
        let hold_tolerance_addresses = [0x15, 0x25, 0x35, 0x45];
        for &test_addr in &hold_tolerance_addresses {
            chip.load_rom_data(vec![test_addr as u8], test_addr)
                .unwrap();

            // Test with different hold times
            for hold_time in [25, 50, 75, 100] {
                let result = test_address_hold_tolerance(
                    &mut chip,
                    &sync_pin,
                    &cm_pin,
                    &ci_pin,
                    &phi1_pin,
                    &phi2_pin,
                    test_addr as u16,
                    test_addr as u8,
                    hold_time,
                );
                assert_eq!(
                    result, test_addr as u8,
                    "Failed address hold tolerance test with {}ns hold time at address {}",
                    hold_time, test_addr
                );
            }
        }

        // Test edge case: voltage and temperature tolerance
        let voltage_temp_addresses = [0x16, 0x26, 0x36, 0x46];
        for &test_addr in &voltage_temp_addresses {
            chip.load_rom_data(vec![test_addr as u8], test_addr)
                .unwrap();

            // Test with different voltage and temperature combinations
            let test_conditions = [
                (4.5, 0.0),   // Low voltage, low temperature
                (5.0, 25.0),  // Nominal voltage, nominal temperature
                (5.5, 50.0),  // High voltage, high temperature
                (4.0, -10.0), // Very low voltage, very low temperature
                (6.0, 70.0),  // Very high voltage, very high temperature
            ];

            for (voltage, temperature) in test_conditions {
                let result = test_voltage_temperature_tolerance(
                    &mut chip,
                    &sync_pin,
                    &cm_pin,
                    &ci_pin,
                    &phi1_pin,
                    &phi2_pin,
                    test_addr as u16,
                    test_addr as u8,
                    voltage,
                    temperature,
                );
                assert_eq!(
                    result, test_addr as u8,
                    "Failed voltage/temperature tolerance test at address {} with {}V, {}°C",
                    test_addr, voltage, temperature
                );
            }
        }

        // Test edge case: voltage tolerance
        let voltage_addresses = [0x17, 0x27, 0x37, 0x47];
        for &test_addr in &voltage_addresses {
            chip.load_rom_data(vec![test_addr as u8], test_addr)
                .unwrap();

            // Test with different voltages
            let test_voltages = [3.5, 4.0, 4.5, 5.0, 5.5, 6.0];
            for voltage in test_voltages {
                let result = test_voltage_tolerance(
                    &mut chip,
                    &sync_pin,
                    &cm_pin,
                    &ci_pin,
                    &phi1_pin,
                    &phi2_pin,
                    test_addr as u16,
                    test_addr as u8,
                    voltage,
                );
                assert_eq!(
                    result, test_addr as u8,
                    "Failed voltage tolerance test at address {} with {}V",
                    test_addr, voltage
                );
            }
        }

        // Test edge case: temperature tolerance
        let temperature_addresses = [0x18, 0x28, 0x38, 0x48];
        for &test_addr in &temperature_addresses {
            chip.load_rom_data(vec![test_addr as u8], test_addr)
                .unwrap();

            // Test with different temperatures
            let test_temperatures = [-20.0, 0.0, 25.0, 50.0, 70.0, 85.0];
            for temperature in test_temperatures {
                let result = test_temperature_tolerance(
                    &mut chip,
                    &sync_pin,
                    &cm_pin,
                    &ci_pin,
                    &phi1_pin,
                    &phi2_pin,
                    test_addr as u16,
                    test_addr as u8,
                    temperature,
                );
                assert_eq!(
                    result, test_addr as u8,
                    "Failed temperature tolerance test at address {} with {}°C",
                    test_addr, temperature
                );
            }
        }

        // Test edge case: manufacturing tolerance
        let manufacturing_addresses = [0x19, 0x29, 0x39, 0x49];
        for &test_addr in &manufacturing_addresses {
            chip.load_rom_data(vec![test_addr as u8], test_addr)
                .unwrap();

            // Test with different manufacturing variations
            let variations = [-20, -10, 0, 10, 20]; // Percentage variation
            for variation in variations {
                let result = test_manufacturing_tolerance(
                    &mut chip,
                    &sync_pin,
                    &cm_pin,
                    &ci_pin,
                    &phi1_pin,
                    &phi2_pin,
                    test_addr as u16,
                    test_addr as u8,
                    variation,
                );
                assert_eq!(
                    result, test_addr as u8,
                    "Failed manufacturing tolerance test at address {} with {}% variation",
                    test_addr, variation
                );
            }
        }

        // Test edge case: manufacturing variation
        let manufacturing_var_addresses = [0x1A, 0x2A, 0x3A, 0x4A];
        for &test_addr in &manufacturing_var_addresses {
            chip.load_rom_data(vec![test_addr as u8], test_addr)
                .unwrap();

            // Test with different manufacturing variation types
            let variation_types = ["FAST", "SLOW", "TYPICAL", "MIN", "MAX"];
            for variation_type in variation_types {
                let result = test_manufacturing_variation(
                    &mut chip,
                    &sync_pin,
                    &cm_pin,
                    &ci_pin,
                    &phi1_pin,
                    &phi2_pin,
                    test_addr as u16,
                    test_addr as u8,
                    variation_type,
                );
                assert_eq!(
                    result, test_addr as u8,
                    "Failed manufacturing variation test at address {} with {} variation",
                    test_addr, variation_type
                );
            }
        }

        // Test edge case: aging tolerance
        let aging_addresses = [0x1B, 0x2B, 0x3B, 0x4B];
        for &test_addr in &aging_addresses {
            chip.load_rom_data(vec![test_addr as u8], test_addr)
                .unwrap();

            // Test with different aging years
            let aging_years = [0, 1, 5, 10, 20, 30];
            for years in aging_years {
                let result = test_aging_tolerance(
                    &mut chip,
                    &sync_pin,
                    &cm_pin,
                    &ci_pin,
                    &phi1_pin,
                    &phi2_pin,
                    test_addr as u16,
                    test_addr as u8,
                    years,
                );
                assert_eq!(
                    result, test_addr as u8,
                    "Failed aging tolerance test at address {} with {} years",
                    test_addr, years
                );
            }
        }

        // Test edge case: aging effect
        let aging_effect_addresses = [0x1C, 0x2C, 0x3C, 0x4C];
        for &test_addr in &aging_effect_addresses {
            chip.load_rom_data(vec![test_addr as u8], test_addr)
                .unwrap();

            // Test with different aging effects
            let aging_effects = ["FRESH", "WORN", "DEGRADED", "FAILING"];
            for aging_effect in aging_effects {
                let result = test_aging_effect(
                    &mut chip,
                    &sync_pin,
                    &cm_pin,
                    &ci_pin,
                    &phi1_pin,
                    &phi2_pin,
                    test_addr as u16,
                    test_addr as u8,
                    aging_effect,
                );
                assert_eq!(
                    result, test_addr as u8,
                    "Failed aging effect test at address {} with {} effect",
                    test_addr, aging_effect
                );
            }
        }

        // Test edge case: extreme condition tolerance
        let extreme_addresses = [0x1D, 0x2D, 0x3D, 0x4D];
        for &test_addr in &extreme_addresses {
            chip.load_rom_data(vec![test_addr as u8], test_addr)
                .unwrap();

            // Test with extreme combinations of voltage, temperature, and aging
            let extreme_conditions = [
                (3.5, -20.0, 30), // Low voltage, low temperature, high aging
                (6.0, 85.0, 30),  // High voltage, high temperature, high aging
                (4.0, 0.0, 20),   // Low voltage, low temperature, medium aging
                (5.5, 70.0, 10),  // High voltage, high temperature, low aging
            ];

            for (voltage, temperature, aging_years) in extreme_conditions {
                let result = test_extreme_condition_tolerance(
                    &mut chip,
                    &sync_pin,
                    &cm_pin,
                    &ci_pin,
                    &phi1_pin,
                    &phi2_pin,
                    test_addr as u16,
                    test_addr as u8,
                    voltage,
                    temperature,
                    aging_years,
                );
                assert_eq!(result, test_addr as u8,
                    "Failed extreme condition tolerance test at address {} with {}V, {}°C, {} years",
                    test_addr, voltage, temperature, aging_years);
            }
        }

        // Test with different access times
        let mut fast_chip = Intel4001::new_with_access_time("FAST_ROM".to_string(), 200);
        fast_chip.base.set_running(true);
        let mut slow_chip = Intel4001::new_with_access_time("SLOW_ROM".to_string(), 750);
        slow_chip.base.set_running(true);

        // Test fast chip
        let fast_address = 0x90;
        let fast_expected = 0x12;
        fast_chip
            .load_rom_data(vec![fast_expected], fast_address)
            .unwrap();

        // Test slow chip
        let slow_address = 0xA0;
        let slow_expected = 0x34;
        slow_chip
            .load_rom_data(vec![slow_expected], slow_address)
            .unwrap();

        // Both chips should work correctly with their respective access times
        // Note: We can't directly test the timing differences without more complex
        // timing simulation, but we can verify that both chips can read data correctly
    }

    #[test]
    fn comprehensive_intel4001_integration_test() {
        // Setup section
        println!("=== Comprehensive Intel 4001 Integration Test: Setup ===");

        // Create Intel4001 with fast access time
        let mut rom = Intel4001::new_with_access_time("TestROM".to_string(), 1); // 1ns for fast access
        rom.base.set_running(true);

        // Load test data: simple arithmetic sequence
        let test_data = vec![
            0x01, 0x02, 0x03, 0x04, 0x05, 0x10, 0x20, 0x30, 0x40, 0x50, 0xFF,
        ];
        rom.load_rom_data(test_data.clone(), 0).unwrap();

        // Verify test data loaded
        for (i, &data) in test_data.iter().enumerate() {
            assert_eq!(rom.read_rom(i as u8).unwrap(), data);
        }

        // Get pin references
        let sync_pin = rom.get_pin("SYNC").unwrap();
        let cm_pin = rom.get_pin("CM").unwrap();
        let ci_pin = rom.get_pin("CI").unwrap();
        let reset_pin = rom.get_pin("RESET").unwrap();
        let phi1_pin = rom.get_pin("PHI1").unwrap();
        let phi2_pin = rom.get_pin("PHI2").unwrap();
        let d0_pin = rom.get_pin("D0").unwrap();
        let d1_pin = rom.get_pin("D1").unwrap();
        let d2_pin = rom.get_pin("D2").unwrap();
        let d3_pin = rom.get_pin("D3").unwrap();

        // Set settlement time to 0 for immediate testing
        sync_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        cm_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        ci_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        reset_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        phi1_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        phi2_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        d0_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        d1_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        d2_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));
        d3_pin
            .lock()
            .unwrap()
            .set_settlement_time(Duration::from_nanos(0));

        // Initially, all data pins should be HighZ
        assert_eq!(d0_pin.lock().unwrap().read(), PinValue::HighZ);
        assert_eq!(d1_pin.lock().unwrap().read(), PinValue::HighZ);
        assert_eq!(d2_pin.lock().unwrap().read(), PinValue::HighZ);
        assert_eq!(d3_pin.lock().unwrap().read(), PinValue::HighZ);

        // Set initial pin states
        // Set reset high initially
        {
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        rom.update();
        assert_eq!(rom.get_timing_state(), TimingState::Idle);
        assert_eq!(rom.get_io_mode(), IoMode::Input);

        // Set reset low
        {
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }

        // Memory Access Verification Section
        println!("=== Memory Access Verification ===");

        // Set data bus to 0 to avoid interference
        for i in 0..4 {
            let pin = rom.get_pin(&format!("D{}", i)).unwrap();
            let mut pin_guard = pin.lock().unwrap();
            pin_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }

        // Ensure state is Idle
        {
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        rom.update();
        {
            let mut reset_guard = reset_pin.lock().unwrap();
            reset_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        rom.update();
        assert_eq!(rom.get_timing_state(), TimingState::Idle);

        // Set SYNC=High, CM=High, CI=Low for memory mode.
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }

        rom.update();
        assert_eq!(rom.get_timing_state(), TimingState::Idle);

        // Now loop over test addresses
        for (i, &expected_data) in test_data.iter().enumerate() {
            let address = i as u8;
            println!(
                "Testing address 0x{:02x} with expected data 0x{:02x}",
                address, expected_data
            );

            // Ensure PHI2 is Low
            {
                let mut phi2_guard = phi2_pin.lock().unwrap();
                phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
            }

            // Ensure PHI1 is Low for rising edge
            {
                let mut phi1_guard = phi1_pin.lock().unwrap();
                phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
            }
            rom.update();

            // PHI1 rising: Address phase
            {
                let mut phi1_guard = phi1_pin.lock().unwrap();
                phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            }
            rom.update();
            assert_eq!(rom.get_timing_state(), TimingState::AddressPhase);

            // Write high nibble
            rom.write_data_bus((address >> 4) & 0x0F);
            rom.update();

            // Write low nibble
            rom.write_data_bus(address & 0x0F);
            rom.update();
            rom.update(); // Additional update to trigger state transition
            assert_eq!(rom.get_timing_state(), TimingState::WaitLatency);

            // Wait for latency (1ns, but since access time is 200ns, need to wait)
            thread::sleep(Duration::from_nanos(10)); // As in existing test

            // PHI2 rising: Data phase
            {
                let mut phi2_guard = phi2_pin.lock().unwrap();
                phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            }
            rom.update();
            assert_eq!(rom.get_timing_state(), TimingState::DriveData);

            // Check data on bus
            let data = rom.read_data_bus();
            assert_eq!(data, expected_data);

            // PHI2 falling: Cleanup
            {
                let mut phi2_guard = phi2_pin.lock().unwrap();
                phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
            }
            rom.update();
            assert_eq!(rom.get_timing_state(), TimingState::Idle);

            // Tri-state pins
            assert_eq!(d0_pin.lock().unwrap().read(), PinValue::HighZ);
            assert_eq!(d1_pin.lock().unwrap().read(), PinValue::HighZ);
            assert_eq!(d2_pin.lock().unwrap().read(), PinValue::HighZ);
            assert_eq!(d3_pin.lock().unwrap().read(), PinValue::HighZ);
        }

        println!("Memory Access Verification completed successfully!");

        // Pin-Level Testing Section
        println!("=== Pin-Level Testing ===");

        // Set control pins to Low for initial state testing
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            let mut phi1_guard = phi1_pin.lock().unwrap();
            let mut phi2_guard = phi2_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }

        // Test each pin's initial state (HighZ for data/IO, Low for control)
        assert_eq!(d0_pin.lock().unwrap().read(), PinValue::HighZ);
        assert_eq!(d1_pin.lock().unwrap().read(), PinValue::HighZ);
        assert_eq!(d2_pin.lock().unwrap().read(), PinValue::HighZ);
        assert_eq!(d3_pin.lock().unwrap().read(), PinValue::HighZ);

        // I/O pins should also be HighZ initially
        let io0_pin = rom.get_pin("IO0").unwrap();
        let io1_pin = rom.get_pin("IO1").unwrap();
        let io2_pin = rom.get_pin("IO2").unwrap();
        let io3_pin = rom.get_pin("IO3").unwrap();
        assert_eq!(io0_pin.lock().unwrap().read(), PinValue::HighZ);
        assert_eq!(io1_pin.lock().unwrap().read(), PinValue::HighZ);
        assert_eq!(io2_pin.lock().unwrap().read(), PinValue::HighZ);
        assert_eq!(io3_pin.lock().unwrap().read(), PinValue::HighZ);

        // Control pins should be Low initially
        assert_eq!(sync_pin.lock().unwrap().read(), PinValue::Low);
        assert_eq!(cm_pin.lock().unwrap().read(), PinValue::Low);
        assert_eq!(ci_pin.lock().unwrap().read(), PinValue::Low);
        assert_eq!(reset_pin.lock().unwrap().read(), PinValue::Low); // After setting to Low
        assert_eq!(phi1_pin.lock().unwrap().read(), PinValue::Low);
        assert_eq!(phi2_pin.lock().unwrap().read(), PinValue::Low);

        // Set drivers for each pin (High, Low) and verify read values
        // Test D0: Set to High
        {
            let mut d0_guard = d0_pin.lock().unwrap();
            d0_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        assert_eq!(d0_pin.lock().unwrap().read(), PinValue::High);

        // Test D0: Set to Low
        {
            let mut d0_guard = d0_pin.lock().unwrap();
            d0_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        assert_eq!(d0_pin.lock().unwrap().read(), PinValue::Low);

        // Test SYNC: Set to High
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        assert_eq!(sync_pin.lock().unwrap().read(), PinValue::High);

        // Test SYNC: Set to Low
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        assert_eq!(sync_pin.lock().unwrap().read(), PinValue::Low);

        // Test HighZ state for data and IO pins
        // D0 back to HighZ
        {
            let mut d0_guard = d0_pin.lock().unwrap();
            d0_guard.set_driver(Some("TEST".to_string()), PinValue::HighZ);
        }
        assert_eq!(d0_pin.lock().unwrap().read(), PinValue::HighZ);

        // IO0 to HighZ (should already be)
        assert_eq!(io0_pin.lock().unwrap().read(), PinValue::HighZ);

        // Simulate clock edges (PHI1/2 rising/falling) and check for state changes
        // Set up for memory access to trigger state changes
        {
            let mut sync_guard = sync_pin.lock().unwrap();
            let mut cm_guard = cm_pin.lock().unwrap();
            let mut ci_guard = ci_pin.lock().unwrap();
            sync_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            cm_guard.set_driver(Some("TEST".to_string()), PinValue::High);
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::Low); // Memory access
        }
        rom.update(); // Update to process pin changes

        // PHI1 rising: Should start address phase
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        rom.update();
        assert_eq!(rom.get_timing_state(), TimingState::AddressPhase);

        // Latch address nibbles to progress state
        rom.write_data_bus(0x00); // High nibble
        rom.update();

        // PHI1 falling
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        rom.update();

        // PHI1 rising again for low nibble
        {
            let mut phi1_guard = phi1_pin.lock().unwrap();
            phi1_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        rom.write_data_bus(0x00); // Low nibble
        rom.update();
        assert_eq!(rom.get_timing_state(), TimingState::WaitLatency);

        // Latency is immediate for testing

        // PHI2 rising: Data phase
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        rom.update();
        assert_eq!(rom.get_timing_state(), TimingState::DriveData);

        // PHI2 falling: Cleanup
        {
            let mut phi2_guard = phi2_pin.lock().unwrap();
            phi2_guard.set_driver(Some("TEST".to_string()), PinValue::Low);
        }
        rom.update();
        assert_eq!(rom.get_timing_state(), TimingState::Idle);

        // Assert pin values match expectations
        // After cleanup, data pins should be HighZ
        assert_eq!(d0_pin.lock().unwrap().read(), PinValue::HighZ);
        assert_eq!(d1_pin.lock().unwrap().read(), PinValue::HighZ);
        assert_eq!(d2_pin.lock().unwrap().read(), PinValue::HighZ);
        assert_eq!(d3_pin.lock().unwrap().read(), PinValue::HighZ);

        println!("Pin-Level Testing completed successfully!");

        // I/O Integration Testing Section
        println!("=== I/O Integration Testing ===");

        // Set CI=High for I/O mode
        {
            let mut ci_guard = ci_pin.lock().unwrap();
            ci_guard.set_driver(Some("TEST".to_string()), PinValue::High);
        }
        rom.update();

        // Test each I/O port (0-3): Set mode to Output, write data, verify port value and direction
        for port in 0..4 {
            println!("Testing I/O port {}", port);

            // Set to Output mode
            rom.set_io_direction(port, IoDirection::Output).unwrap();
            rom.set_io_mode(IoMode::Output);
            rom.update();

            // Write data to port
            let test_value = ((port + 1) * 0x05) as u8; // 0x05, 0x0A, 0x0F, 0x14
            rom.set_io_port(port, test_value).unwrap();
            rom.update();

            // Verify port value
            assert_eq!(rom.get_io_port(port).unwrap(), test_value);

            // Verify direction
            assert_eq!(rom.get_io_direction(port).unwrap(), IoDirection::Output);

            // Test I/O direction control and data flow
            // In output mode, data should be driven to I/O pins
            // Note: In real hardware, output would drive the pin, but in this sim, it's internal
            // For testing, we check the latch
            assert_eq!(rom.get_output_latch(), test_value);
        }

        // Test Input mode
        for port in 0..4 {
            println!("Testing I/O port {} in Input mode", port);

            rom.set_io_direction(port, IoDirection::Input).unwrap();
            rom.set_io_mode(IoMode::Input);
            rom.update();

            // Set port value for input
            let input_value = ((port + 1) * 0x03) as u8; // 0x03, 0x06, 0x09, 0x0C
            rom.set_io_port(port, input_value).unwrap();
            rom.update();

            // Verify port value
            assert_eq!(rom.get_io_port(port).unwrap(), input_value);

            // Verify direction
            assert_eq!(rom.get_io_direction(port).unwrap(), IoDirection::Input);

            // In input mode, reading should get the value
            assert_eq!(rom.get_input_latch(), input_value);
        }

        // Test RDM/WRM operations via control pins
        // Simulate WRM (Write ROM, but for I/O)
        rom.set_io_mode(IoMode::Output);
        rom.write_data_bus(0x0F); // Data to write
        rom.update();
        // For port 0
        rom.write_data_bus(0x00); // Address port 0
        rom.update();
        // This should set the port
        assert_eq!(rom.get_io_port(0).unwrap(), 0x0F);

        // Simulate RDM (Read Data Memory, for I/O)
        rom.set_io_mode(IoMode::Input);
        rom.write_data_bus(0x00); // Address port 0
        rom.update();
        // Should read the value
        assert_eq!(rom.get_input_latch(), 0x0F);

        println!("I/O Integration Testing completed successfully!");

        // Debugging Features Section
        println!("=== Debugging Features ===");

        // Include comprehensive logging and state inspection
        rom.debug_state_transitions("Comprehensive Test");

        // Provide pin state snapshots at each test phase
        println!(
            "Final Pin states: SYNC: {:?}, CM: {:?}, CI: {:?}, PHI1: {:?}, PHI2: {:?}",
            sync_pin.lock().unwrap().read(),
            cm_pin.lock().unwrap().read(),
            ci_pin.lock().unwrap().read(),
            phi1_pin.lock().unwrap().read(),
            phi2_pin.lock().unwrap().read()
        );

        println!(
            "Data pins: D0: {:?}, D1: {:?}, D2: {:?}, D3: {:?}",
            d0_pin.lock().unwrap().read(),
            d1_pin.lock().unwrap().read(),
            d2_pin.lock().unwrap().read(),
            d3_pin.lock().unwrap().read()
        );

        println!(
            "I/O pins: IO0: {:?}, IO1: {:?}, IO2: {:?}, IO3: {:?}",
            io0_pin.lock().unwrap().read(),
            io1_pin.lock().unwrap().read(),
            io2_pin.lock().unwrap().read(),
            io3_pin.lock().unwrap().read()
        );

        // Enable step-through debugging of memory access cycles
        // (Already done in memory access section)

        // Include failure analysis and diagnostic information
        // If any assertion fails, the test will stop with details

        println!("Debugging Features completed successfully!");

        // Test Data Section
        println!("=== Test Data ===");

        // Use a known test program (e.g., simple arithmetic sequence)
        // Already loaded: vec![0x01, 0x02, 0x03, 0x04, 0x05, 0x10, 0x20, 0x30, 0x40, 0x50, 0xFF]

        // Include edge case data patterns for thorough testing
        let edge_cases = vec![
            (0x00, "All zeros"),
            (0xFF, "All ones"),
            (0x55, "Alternating bits"),
            (0xAA, "Alternating bits inverted"),
            (0x0F, "Low nibble ones"),
            (0xF0, "High nibble ones"),
        ];

        for (data, desc) in edge_cases {
            println!("Testing edge case: {} (0x{:02x})", desc, data);
            rom.load_rom_data(vec![data; 256], 0).unwrap();
            let read_data = rom.read_rom(0).unwrap();
            assert_eq!(read_data, data, "Failed for {}", desc);
        }

        // Provide both valid and invalid test scenarios
        // Valid: addresses 0-255
        for addr in 0..10 {
            // Test first 10
            let data = rom.read_rom(addr).unwrap();
            assert_eq!(data, 0x00); // Since we loaded all zeros last
        }

        // Test boundary address 0xFF
        assert_eq!(rom.read_rom(255).unwrap(), 0x00); // Since we loaded all zeros

        println!("Test Data completed successfully!");

        println!("Comprehensive Intel 4001 Integration Test completed successfully!");
    }
}