nRF91: UART async read

[kk2mkk]

Hi,

What is the best way to read the async data received on a UART in to a buffer when ever there is an a byte available and  in a separate task read the data from the buffer as and when needed.

reards

KK

[Håkon Alseth]

Hi,

 

For receiving uart data byte-for-byte, you can set up your project similar to this:

https://github.com/Rallare/fw-nrfconnect-nrf/blob/nrf9160_samples/samples/nrf9160/uart/src/main.c

 

But, I would recommend that you do as little processing as possible in the UART interrupt handler, by for instance passing the data to a FIFO or using a system workqueue, or which ever other method you prefer.

If you require more advance uart handling (with RX timeouts, specific sizes, etc), I would recommend that you look into the uart_async module. There's a test-program for it here, which includes several uses of it:

https://github.com/NordicPlayground/fw-nrfconnect-zephyr/tree/master/tests/drivers/uart/uart_async_api

 

Kind regards,

Håkon

[kk2mkk]

Hi Hakon,

Mean while i have figured it out the way you suggested in your first link, but i am ring_buf_put() to collect byte by byte in ISR call back and in task i use ring_buf_get() to get the data when ever needed, i hope ring_buf_put() is not bulky to use in ISR?

regards

KK

[Håkon Alseth]

Hi KK,

 

That should be fine. The documentation even lists uart reception as one of the main use-cases:

https://docs.zephyrproject.org/latest/reference/kernel/other/ring_buffers.html

 

Kind regards,

Håkon