circuitpython/examples/rp2/pio_1hz.py

36 lines
871 B
Python

# Example using PIO to blink an LED and raise an IRQ at 1Hz.
import time
from machine import Pin
import rp2
@rp2.asm_pio(set_init=rp2.PIO.OUT_LOW)
def blink_1hz():
# fmt: off
# Cycles: 1 + 1 + 6 + 32 * (30 + 1) = 1000
irq(rel(0))
set(pins, 1)
set(x, 31) [5]
label("delay_high")
nop() [29]
jmp(x_dec, "delay_high")
# Cycles: 1 + 7 + 32 * (30 + 1) = 1000
set(pins, 0)
set(x, 31) [6]
label("delay_low")
nop() [29]
jmp(x_dec, "delay_low")
# fmt: on
# Create the StateMachine with the blink_1hz program, outputting on Pin(25).
sm = rp2.StateMachine(0, blink_1hz, freq=2000, set_base=Pin(25))
# Set the IRQ handler to print the millisecond timestamp.
sm.irq(lambda p: print(time.ticks_ms()))
# Start the StateMachine.
sm.active(1)