stm32: flow= parameter in pyb.UART().init() #1981
Description
When initializing an UART with u3 = pyb.UART(3, 57600) the default settings are set to no flow control (flow=0). It would be 'better' when None would be used instead of 0. Furthermore when using u3 at REPL the current initialization is shown, but flow is omitted if 0.
I would like to see flow=None or flow=RTS in all cases. Furthermore any value can be entered setting "stray" bits so it would be 'better' to mask off all bits except for RTS and CTS.
I have changed these in stmhal\uart.c and added to my fork, but it seems to me these could be integrated in the mpy code base.
If I only knew how to git that....