# Experiment F: D Flip-Flop with Programmable Clock
import machine
import utime

# --- Pins for Monitoring ---
Q_PIN = machine.Pin(16, machine.Pin.IN)    # Reads Q from flip-flop
Q_NOT_PIN = machine.Pin(17, machine.Pin.IN) # Reads Q̅ from flip-flop

# --- Pin for Generating Clock (GP18) ---
CLOCK_PIN = machine.PWM(machine.Pin(18))
CLOCK_FREQ = 100  # 100 Hz = 100 pulse per second
CLOCK_PIN.freq(CLOCK_FREQ)
CLOCK_PIN.duty_u16(32768)  # 50% duty cycle

# --- Optional: Button to change Data input ---
# If you connected a button to GP19 for Data
# DATA_BUTTON = machine.Pin(19, machine.Pin.IN, machine.Pin.PULL_UP)

print("🧠 Experiment F: D Flip-Flop with Programmable Clock")
print("=" * 60)
print("SETUP:")
print("• Pico GP18 -> Flip-Flop CLK (Auto clock at 100 Hz)")
print("• Flip-Flop Q -> Pico GP16 (Monitor)")
print("• Flip-Flop Q̅ -> Pico GP17 (Monitor)")
print("• Data (D) pin: Connect to HIGH (3.3V) or LOW (GND)")
print("-" * 60)
print("ACTIONS:")
print("• Manually CHANGE the D input (HIGH/LOW)")
print("• Watch LEDs update on the next clock pulse")
print("-" * 60)

def monitor_flip_flop():
    """Reads and returns the state of the flip-flop."""
    q_state = Q_PIN.value()
    q_not_state = Q_NOT_PIN.value()
    
    if q_state == q_not_state:
        return "⚠️  ERROR: Q and Q̅ should be opposites!"
    else:
        bit_value = q_state
        return f"Stored Bit: {bit_value} | Q: {'HIGH' if q_state else 'LOW'}, Q̅: {'HIGH' if q_not_state else 'LOW'}"

try:
    counter = 0
    while True:
        status = monitor_flip_flop()
        # Print with clock cycle counter
        print(f"Clock Cycle: {counter:3d} | {status}", end='\r')
        counter += 1
        utime.sleep(1)  # Wait 1 second per clock cycle

except KeyboardInterrupt:
    CLOCK_PIN.deinit()  # Turn off clock signal
    print("\n\n✅ Experiment stopped. Clock halted.")