Ad the ability to read the PIO PC location?

[dclaar]

The code doesn't currently support reading the PIO PC. Would this be a reasonable thing to add?

Use case:

I found this interesting PIO button debouncer. You determine the button state by reading the PIO PC with pio_sm_get_pc. I think most of the rest of it is already possible with the existing PIO support: Would it be reasonable to add this functionality?

[peterhinch]

I'm agnostic on reading the PIO PC.

In the specific use case of a debouncer I don't think it's a very good API, requiring the user code to regularly poll N state machines. You really want each debounced switch to trigger a callback or set an asyncio.Event on a state change, so that asynchronous switch operations can trigger a response.

At the moment I can't think of a neat way of doing this with multiple SM's.

[dclaar]

Thanks! I have 5 switches to read, which is why I thought that it would be cool to know that, whenever I read them, they would return a debounced value. In other architectures (e.g. ATMEL), I'd just put them all on PORT A or B, and read them all at once, but that doesn't exist on the Pico.

I'll probably just end up doing the "CircuitPython" way of reading them in a loop, or do asyncio as you say.

[peterhinch]

If you're prepared to use asyncio, drivers may be found here.

[GitHubsSilverBullet]

You can use a viper function:

# -*- coding: UTF-8 -*-
# vim: fileencoding=utf-8: ts=4: sw=4: expandtab:

@micropython.viper
def pio_pc(sm: int) -> int:
    p0: ptr32 = ptr32(1344274432)
    p1: ptr32 = ptr32(1345323008)
    if sm < 4:  return p0[53 + sm * 6]
    else:       return p1[53 + (sm-4) * 6]