PyBoard - Non-blocking console I/O

[etherbrat]

I have tried a couple of searches with no luck. It seems obvious (to me) that a board designed for real-time and IoT functions should be able to do console I/O (character- or byte-wise) without blocking the idle loop. I can find docs that indicate this is possible with STM32 UARTS, but not with the USB console on the PyBoard. There are work-arounds that allow this with mainstream Python. Does anyone have code snippet? It would be a lot easier than having to lash up RS-232 comms via a UART.

[IlysvlVEizbr]

Do you mean you want to use the USB interface on the pyboard in the form of serial communication? This is possible, you can refer to the USB_VCP part of the documentation, it works very much like a UART.

As for the usage of non-blocking, there are two ways that I know, one is to use multi-threading (use _thread, refer to this), and the other is to use asynchronous I/O (refer to this). The latter is more difficult to get started, I recommend using _thread.

Tips: If you need to use _thread, you need to install the Threading version firmware on pyboard.

[jimmo]

If you're using it via stdin, you can use select/poll. https://docs.micropython.org/en/latest/library/select.html

(This is easy to use via asyncio as @IlysvlVEizbr mentions above. See for example the aiorepl package which does non-blocking reads from stdin -- https://github.com/micropython/micropython-lib/blob/master/micropython/aiorepl/aiorepl.py#L94 )

If you detach the USB_VCP from stdin (via dupterm), then you can also use it directly as a stream. It implements the necessary bits to be used via select/poll too (I haven't tested it recently, but it's supposed to work).

[etherbrat]

Got it! Thanks to all.