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# Example using PIO to wait for a pin change and raise an IRQ.
#
# Demonstrates:
# - PIO wrapping
# - PIO wait instruction, waiting on an input pin
# - PIO irq instruction, in blocking mode with relative IRQ number
# - setting the in_base pin for a StateMachine
# - setting an irq handler for a StateMachine
# - instantiating 2x StateMachine's with the same program and different pins
# ruff: noqa: F821 - @asm_pio decorator adds names to function scope
import time
from machine import Pin
import rp2
@rp2.asm_pio()
def wait_pin_low():
wrap_target()
wait(0, pin, 0)
irq(block, rel(0))
wait(1, pin, 0)
wrap()
def handler(sm):
# Print a (wrapping) timestamp, and the state machine object.
print(time.ticks_ms(), sm)
# Instantiate StateMachine(0) with wait_pin_low program on Pin(16).
pin16 = Pin(16, Pin.IN, Pin.PULL_UP)
sm0 = rp2.StateMachine(0, wait_pin_low, in_base=pin16)
sm0.irq(handler)
# Instantiate StateMachine(1) with wait_pin_low program on Pin(17).
pin17 = Pin(17, Pin.IN, Pin.PULL_UP)
sm1 = rp2.StateMachine(1, wait_pin_low, in_base=pin17)
sm1.irq(handler)
# Start the StateMachine's running.
sm0.active(1)
sm1.active(1)
# Now, when Pin(16) or Pin(17) is pulled low a message will be printed to the REPL.
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