circuitpython/examples/rp2/pio_pinchange.py
Angus Gratton 861fbf6ab5 examples: Mark asm, pio, etc. as noqa: F821 (undefined-name).
These files all use decorators (@asm_thumb, @asm_pio) that add names to the
function scope, that the linter cannot see.

It's useful to clear them in the file not in pyproject.toml as example code
will be copied and adapted elsewhere, and those developers may also use
Ruff (we hope!)

Signed-off-by: Angus Gratton <angus@redyak.com.au>
2023-08-16 16:12:33 +10:00

49 lines
1.2 KiB
Python

# 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.