Hard fault using .send() inside asyncio #10329

phlidwsn · 2025-05-09T01:54:25Z

Not sure if this is an actual issue that could be guarded against or just a neat way for the user(me) to be an idiot, but the following code causes a hard fault in CircuitPython.

Occurs when using .send() instead of .asyncio_send(). .asyncio_send() in the same code works just fine.

Hardware: Adafruit RP2040 RFM95 915Mhz

Code:

import board
import digitalio
from adafruit_rfm import rfm9x
import asyncio

class TestCode:
    def __init__(self):
        # Define radio frequency in MHz. Must match your
        # module. Can be a value like 915.0, 433.0, etc.
        RADIO_FREQ_MHZ = 915.0

        # Define Chip Select and Reset pins for the radio module.
        CS = digitalio.DigitalInOut(board.RFM_CS)
        RESET = digitalio.DigitalInOut(board.RFM_RST)

        # Initialise RFM95 radio
        self.radio = rfm9x.RFM9x(board.SPI(), CS, RESET, RADIO_FREQ_MHZ)
        self.radio.enable_crc = True
        self.radio.spreading_factor = 8
    
    async def xmit_job(self):
        while True:
            print("sending")
            self.radio.send(bytes("dsaklfjlkdsjflkasjdflkasjkljfklasjdflkjasdlkfjaskldjlkjfiasdjfalksdjfkalsdjf", "utf-8"))
            await asyncio.sleep(10)
            
    
    async def recv_job(self):
        pass
    
    async def main(self):
        await asyncio.gather(
            self.xmit_job(),
            self.recv_job()
                             )




test = TestCode()
asyncio.run(test.main())

"""
result:
Running in safe mode! Not running saved code.

You are in safe mode because:
CircuitPython core code crashed hard. Whoops!
Hard fault: memory access or instruction error.
Please file an issue with your program at github.com/adafruit/circuitpython/issues.
Press reset to exit safe mode.
"""

The text was updated successfully, but these errors were encountered:

jerryneedell · 2025-05-09T14:30:03Z

Hmmm. Nice catch!
Hopefully, an acceptable temporary work around is "don't do that" 😉

It would be nice to track down the root cause. Is it something in asyncio or is there a way to trap it without the hard fault.
Is there any reason why it should actually work?

tannewt · 2025-05-09T18:01:47Z

Can you get the hard fault without the RFM library? I'll move this issue to the core since it is a crash.

6D0C

tannewt transferred this issue from adafruit/Adafruit_CircuitPython_RFM May 9, 2025

tannewt added bug crash rp2040 Raspberry Pi RP2040 async asyncio related labels May 9, 2025

tannewt added this to the 10.0.x milestone May 9, 2025

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