from machine import Pin
import time

# Define LED pins (check your wiring!)
red_led = Pin(0, Pin.OUT)
green_led = Pin(1, Pin.OUT)
blue_led = Pin(2, Pin.OUT)
yellow_led = Pin(3, Pin.OUT)

# Function to blink an LED
def blink_led(led_pin):
    led_pin.on()  # Turn the LED on
    time.sleep(0.5)  # Wait for 500ms
    led_pin.off()  # Turn the LED off
    time.sleep(0.5)  # Wait for 500ms

# Debug message to ensure Pico is running
print("Raspberry Pi Pico LED Blink Program")
print("Press 'U' for Up, 'D' for Down, 'R' for Right, 'L' for Left to blink an LED.")

# Main program loop
while True:
    # Read user input via REPL (serial terminal)
    user_input = input().strip().upper()  # Read input from the serial terminal

    # Debugging: print the input for troubleshooting
    print(f"User input received: {user_input}")

    # Check for valid key presses and blink the corresponding LED
    if user_input == "U":
        print("Blinking Red LED (Up Arrow)")
        blink_led(red_led)  # Blink red LED for up arrow
    elif user_input == "D":
        print("Blinking Green LED (Down Arrow)")
        blink_led(green_led)  # Blink green LED for down arrow
    elif user_input == "R":
        print("Blinking Blue LED (Right Arrow)")
        blink_led(blue_led)  # Blink blue LED for right arrow
    elif user_input == "L":
        print("Blinking Yellow LED (Left Arrow)")
        blink_led(yellow_led)  # Blink yellow LED for left arrow
    else:
        print("Invalid input! Please press U, D, R, or L.")