QUERY · ISSUE

rp2: Crash with hard pin IRQ

openby peterhinchopened 2021-02-24updated 2021-05-05

bugport-rp2

Measuring hard IRQ latency with this script:

from machine import Pin, PWM
from time import sleep_ms
import math
# Link 16-17, time 16-18
pin18 = Pin(18, Pin.OUT)

def callback(_):
    pin18(1)  # Trigger
    pin18(0)

pin17 = Pin(17, Pin.IN)
_ = pin17.irq(callback, trigger=Pin.IRQ_RISING, hard=True)

pwm = PWM(Pin(16))
pwm.freq(1000)
pwm.duty_u16(0xffff // 2)

while True:
    y = 0
    for x in range(100):
        y += math.sin(x * 2 * math.pi/100)  # 6.2ms of busywork
    sleep_ms(10)

The usual latency was a creditable 25μs, but I have measured 100μs. It was not practicable to measure a worst case because the the machine suffers a hard crash usually almost immediately. If I comment out the busywork, leaving just the sleep_ms(10), it runs indefinitely with about 20μs latency.

CANDIDATE · ISSUE

Crash on RP2 with pin IRQ's

closedby peterhinchopened 2023-01-22updated 2023-01-23

bugport-rp2

The problem has appeared on nightly builds since 20th Dec. This build fails: rp2-pico-20230120-unstable-v1.19.1-831-g4f3780a15.uf2. The following is the smallest repro I've come up with so far:

import uasyncio as asyncio
from machine import Pin

class Encoder:

    def __init__(self):
        pin_x = Pin(20, Pin.IN, Pin.PULL_UP)
        pin_y = Pin(17, Pin.IN, Pin.PULL_UP)
        self._x = 0
        self._y = 0
        self._v = 0
        trig = Pin.IRQ_RISING | Pin.IRQ_FALLING
        pin_x.irq(trigger=trig, handler=self._x_cb, hard=False)
        pin_y.irq(trigger=trig, handler=self._y_cb, hard=False)

    def _x_cb(self, pin_x):
        print('x')
        if (x := pin_x.value()) != self._x:  # Crash seems to occur here
            pass

    def _y_cb(self, pin_y):
        print('y')
        if (y := pin_y.value()) != self._y:  # or here
            pass

async def main():
    e = Encoder()
    while True:
        await asyncio.sleep(1)
        print(e._v)

asyncio.run(main())

When either pin changes state the ISR prints then the board crashes. If I reduce the ISR's to just a print statement the code runs. Note hard and soft IRQ's behave similarly.

rp2: Crash with hard pin IRQ

Crash on RP2 with pin IRQ's

Keyboard