Serial 9 bit.

[Christer_A]

I have a project where a server is using RS485. 1 start bit, 8 databita, 1 ’Parity’ bit and 2 stop bits.
But the Parity bit is a Command bit for special signal to a receiver. So it is more like 9 bits.
I need a way/library to be able to read the Parity bit.

[adafruit_support_bill]

But the Parity bit is a Command bit for special signal to a receiver. So it is more like 9 bits.

Most hardware UART implementations will swallow the parity bit and only give you an indication if the parity check fails. You will probably need to start with a software implementation and add some tweaks to allow you to read the parity directly. There are several software serial libraries out there. The best is probably PJRC's AltSoftSerial:
https://www.pjrc.com/teensy/td_libs_AltSoftSerial.html

[Christer_A]

HW Serial read on Feather M0 or Feather Huzzah32. Serial.begin(9600,SERIAL_8E2);
…. and in the void loop() use
If (Serial.available() >0…..

The transmitted data use 9600, ”parity”, 2 stopp bits. BUT ! The ”parity” bit is not used for parity but for a special control signal. So the detected data could have a correct or wrong parity bit.
Will the uart still present the 8 databits and be shown when reading by the code or will the data be ignored and not shown if the parity bit is considered as wrong

[adafruit_support_bill]

See section 26 of the M0 datasheet for details on the USART operation: https://ww1.microchip.com/downloads/en/ ... 01882F.pdf
It looks like a parity error on receive will set the error bit & the data will still be available.

[Christer_A]

Thank you !!!