uasyncio streamreader hanging on uart.readline

[p_j]

I'm seeing some strange behaviour when using streamreader. ESP32-S2, micropython latest from github.

When I call readline() on the streamreader it never returns, even though lines of text are being sent to the UART.

When I call read() I can read the bytes individually.

Example:

This code hangs

Code: Select all

async def _run(self):
    self._sreader = asyncio.StreamReader(self.uart)

    while True:
        res = await self._sreader.readline()

This works ok (but I have to manually process the buffer periodically)

Code: Select all

async def _run(self):
    self._sreader = asyncio.StreamReader(self.uart)

    while True:
        await asyncio.sleep_ms(50)
        ava = self.uart.any()
        res = await self._sreader.read(ava)
        self.rx_buffer += res.decode('utf8')
        

Any ideas?

[pythoncoder]

Hmm. I'm getting no joy at all. According to the docs for my Feather S2 the rx and tx pins are connected to UART 0. However a simple loopback test doesn't work. .any() returns some stupid number. .write(b'hello\n') returns nothing (should return 6). And .read() produces nothing.

I tried UART 1: .write and .any returned sensible numbers but .read never produced anything.

Which UART and I/O pins are you using?

[p_j]

Hmm. I'm getting no joy at all. According to the docs for my Feather S2 the rx and tx pins are connected to UART 0. However a simple loopback test doesn't work. .any() returns some stupid number. .write(b'hello\n') returns nothing (should return 6). And .read() produces nothing.

I tried UART 1: .write and .any returned sensible numbers but .read never produced anything.

Which UART and I/O pins are you using?

Thanks Peter, I'm using UART0 with pins 37/38

UART(0, baudrate=115200, tx=37, rx=38, timeout=0)

I did have to make a small change in machine_uart.c in order to use UART0 on the ESP32-S2 so let me revert my changes and see if the same behaviour happens in UART0 for me. There is probably a valid reason why UART0 isn't available on the S2 for general use.

I will report back!

[p_j]

Further strangeness.

When I compile Micropython with TinyUSB disabled the uasyncio streamreader works as expected.

I imagine this is something to do with the differences between the ESP32 and ESP32-S2 possibly. I'm going to continue with usb disabled for now and come back to do some more debugging on this later.

Will raise an issue when I have more info.