Asynchronous ADC timed readings

[saraverbeecke]

For the stm32 port it is possible to read the ADC in a timed manner. See docs. Should it be possible to use this in a non-blocking way?
@peterhinch has a very useful asynchronous implementation for reading and waiting an ADC, but this is implemented for a single read see AADC.

[Josverl]

The docs you linked to explicitly state that the function is blocking.

This function does not allocate any heap memory. It has blocking behaviour: it does not return to the calling program until the buffer is full.

Can you explain what you are trying to achieve?

[saraverbeecke]

Hi thanks for looking into this. Indeed it says blocking so a no-go I suppose.
I would like to read out some values at a certain sample rate (1kHz) but need to be able to await this so I can do other stuff while the ADC values are being buffered...

[peterhinch]

1KHz is too fast for an asyncio solution. One approach would be to do the ADC read in a hard ISR. The micropython-filters repo illustrates realtime data capture on STM32. The lpf.py demo uses a timer ISR to capture data.

[saraverbeecke]

OK thanks for the info. The LPF demo looks great, I'll try that approach on my stm32f411.

[peterhinch]

Just to clarify, your application can use asyncio so long as your data capture is by ISR.