use of select.poll() with multiple uarts

[roland_vs]

I work with three serial ports and I would like to handle these within the program. So I use USB-VCP exclusively for debugging.

I have an uart 3 that communicates to a host, I have uart 1, uart 2 and uart 6 ready to go. So data may be coming from everywhere.
How does one use the select.poll() in such occasion to see which port to service?

Greetings,

R.

[dhylands]

The documentation is here: http://docs.micropython.org/en/latest/p ... elect.html

I was able to put together a simple example:

Code: Select all

import pyb
import select

# assume UART4 Tx (X1) connected to UART6 Rx (Y2)

u4 = pyb.UART(4, 9600)
u6 = pyb.UART(6, 9600)

u4.write('123')

poll = select.poll()
poll.register(u6, select.POLLIN)
while True:
    events = poll.poll()
    print('events =', events)
    for file in events:
        # file is a tuple
        if file[0] == u6:
            ch = u6.read(1)
            print('Got ', ch)

which gives the following output:

Code: Select all

>>> import poll_uart
events = [(UART(6, baudrate=9600, bits=8, parity=None, stop=1, timeout=1000, timeout_char=2, read_buf_len=64), 1)]
Got  b'1'
events = [(UART(6, baudrate=9600, bits=8, parity=None, stop=1, timeout=1000, timeout_char=2, read_buf_len=64), 1)]
Got  b'2'
events = [(UART(6, baudrate=9600, bits=8, parity=None, stop=1, timeout=1000, timeout_char=2, read_buf_len=64), 1)]
Got  b'3'
... and it stops here waiting for more data on the uart...

[roland_vs]

@dhylands This works like a charm. I added some more UARTS and have data coming from all sides!

[oceanq]

Would select.poll() be the most efficient way to deal with logging asci data that is on multiple uarts?
I have 3 UARTS, two of the UARTS are sending data at a 1 second interval (gps, and another sensor), the third UART has a data rate that varies between 0.75 and 1.25 seconds.
If I modified the simple example, and wrote a while loop for each of the UARTS, would it be fast enough to open the file, append-write the data, close the file and flush the buffer on each of the UARTS?
Is there a way to prioritize the UARTS, so the most important data does not get missed?
Could the UART data be concatenated into a single append-write?
Thank you!