APP UART COMMUNICATION ERROR eror code

RE: APP UART COMMUNICATION ERROR eror code

aep — Sun, 06 Mar 2016 11:33:32 GMT

@RK Hmm. I'll try to make a full logic analysis including CTS/RTS when i get the time. I did see a difference when enabling flow control, so i dont think it plain didn't work at all. It just didn't fix the issue i had. Just not blocking fixed it.

RE: APP UART COMMUNICATION ERROR eror code

RK — Sat, 05 Mar 2016 13:43:00 GMT

Sorry but neither of those two conclusions really make much sense. Flow control when enabled on both sides with RTS/CTS connected absolutely stops the UART in both directions from overflowing its buffer. That has nothing at all to do with the softdevice nor interrupt priorities or anything else. As long as the RTS/CTS are deasserted, you can take as long as you like to service the UART, cycles, milliseconds or seconds and it and the other end will just sit there quietly and wait for buffer space to become available.

So what you're seeing has to be something else.

RE: APP UART COMMUNICATION ERROR eror code

aep — Sat, 05 Mar 2016 12:07:00 GMT

(edit: might not be the correct answer?)

Turns out that i incorrectly assumed turning on flow control would allow me to block the uart event handler for longer than one cycle. Apparantly flow controll doesn't work that way or is too slow or something.

Even with flowcontroll enabled , do not block the uart event handler

Also the uart event handler must be a high priority interrupt, otherwise the softdevice breaks it. The internal hw buffer is just 6 bytes or so, that leaves enough cpu time to put those bytes into an app_fifo and trigger event scheduler to call a function on the mainloop with lower priority to parse the data.

RE: APP UART COMMUNICATION ERROR eror code

Ole Bauck — Fri, 04 Mar 2016 09:39:49 GMT

You can get FRAMING or BREAK errors if the transmitting device restarts, could that be the case? Do you get the error often? If you are using the APP_ERROR_HANDLER on the error I would consider changing it to a more suitable error handler, because APP_ERROR_HANDLER will either reset the chip or go into infinite while loop, see here.

RE: APP UART COMMUNICATION ERROR eror code

aep — Thu, 03 Mar 2016 15:48:47 GMT

bah of course i used the wrong file, thanks Ole.

with app_uart_fifo i just get APP_UART_COMMUNICATION_ERROR with error code 4 and no other event.

All of this is with or without flow control btw, but with flow control its a tiny bit better.

RE: APP UART COMMUNICATION ERROR eror code

Ole Bauck — Thu, 03 Mar 2016 10:18:09 GMT

Sounds like that. Are you using app_uart.c or app_uart_fifo.c? You should use the fifo file. Are you running an example?

RE: APP UART COMMUNICATION ERROR eror code

aep — Wed, 02 Mar 2016 18:12:34 GMT

Yeap, My logic analyzer shows its matching up fine. Curiously i receive exactly 5 or 6 characters until i get an error. It sounds like the fifo doesnt actually work and the internal hw buffer is just 6 bytes.

RE: APP UART COMMUNICATION ERROR eror code

Ole Bauck — Wed, 02 Mar 2016 16:27:59 GMT

The uart_evt->data.error_communication is equal to the ERRORSRC register, see here (same for nRF51). You are receiving OVERRUN, FRAMING and BREAK errors which can occur if you are using the wrong baudrate. Have you configured the same baudrate on both sides of the UART?