from machine import Pin
from rp2 import PIO, StateMachine, asm_pio
import time
from time import sleep


# Define stepper motor pins and control pins
stepper_pins = [Pin(18, Pin.OUT), Pin(19, Pin.OUT), Pin(20, Pin.OUT), Pin(21, Pin.OUT)]  
sw_pin = Pin(1, Pin.IN)  # Switch pin
led_pin = Pin(2, Pin.OUT)  # LED pin


@asm_pio(set_init=(PIO.OUT_LOW,)*4)
def stepper():
    label("start")
    set(pins, 8)   # Step 1 (CW)
    set(x, 31)     # Delay for 31 cycles (for step rate of 10 Hz)
    label("delay1")
    nop()          # No operation for delay
    jmp(x_dec, "delay1")  # Decrease x and repeat until zero
    set(pins, 4)   # Step 2 (CW)
    set(x, 31)
    label("delay2")
    nop()
    jmp(x_dec, "delay2")
    set(pins, 2)   # Step 3 (CW)
    set(x, 31)
    label("delay3")
    nop()
    jmp(x_dec, "delay3")
    set(pins, 1)   # Step 4 (CW)
    set(x, 31)
    label("delay4")
    nop()
    jmp(x_dec, "delay4")
    jmp("start")   # Repeat the process to rotate clockwise


# Initialize the state machine for the stepper motor with a 10 Hz step rate
sm = StateMachine(0, stepper, freq=2000, set_base=stepper_pins[0])


# Main loop
while True:
    if sw_pin.value() == 0:  # If switch is pressed (active low)
        led_pin.toggle()  # Turn LED on
        sm.active(1)  # Start stepper motor
    else:
        led_pin.toggle()  # Blink LED at 2 Hz (500 ms ON and OFF)
        sm.active(0)  # Stop stepper motor
        sleep(0.5)  # Blink delay (500 ms)