USART receiving 8-bit data with parity

[Robert Ritchey]

I am supposed to be receiving 8-bit data with even parity.  The blocks are defined with a header of 'F0', this is S.Bus data if anyone knows that that is.  I setup a simple program that just does receive data.  I get data but nowhere does it show an 'F0'.  Am I supposed to use 'LL_USART_ReceiveData8' or 'LL_USART_ReceiveData9' to read this data?  Is the parity supposed to be read with the data and discarded?  It's not at all clear how the parity is handled. 

[waclawek.jan]

Try to transmit and observe the signal you've transmitted.

JW

[Robert Ritchey · Accepted solution]

You are correct.  I had the pin inverted at first, then re-read the documention, and set it to non-inverted. You try to make sense of this:

Bit 16 RXINV: RX pin active level inversion
This bit is set and cleared by software.
0: RX pin signal works using the standard logic levels (VDD =1/idle, Gnd=0/mark)
1: RX pin signal values are inverted (VDD =0/mark, Gnd=1/idle).

Anyway, I misread this documentation.   The 9-bit data is correct with parity.  I don't know what you mean by "2 parity" bits.  The format is 8-bit data, parity and 2 stop bits.  

It works now, at least I get the "0F" where I expect it.  I need to check the number if IDLEs I got. 

Thanks for sticking with me though this. 

[Robert Ritchey]

Thanks for stick with me though this.  The data was inverted.  I misread the documentation.  It's confusing as to what the USART expects.  

Bit 16 RXINV: RX pin active level inversion
This bit is set and cleared by software.
0: RX pin signal works using the standard logic levels (VDD =1/idle, Gnd=0/mark)
1: RX pin signal values are inverted (VDD =0/mark, Gnd=1/idle).