Access to UART with DMA under example "freertos_coap_server" SDK nRF52840-DK

[alex]

Good day!
Tell me how you can configure access to UART with DMA in the example freertos_coap_server for receiving and transmitting arbitrary messages. Also, please clarify what maximum write read buffer is available in DMA for UART?

Thank's

[Hung Bui]

Hi Alexander, 

As long as you don't use UART in blocking mode, but in interrupt mode it should work fine with the freertos_coap_server. We provided the app_uart_fifo library that you can use. Please have a look at the peripheral\uart example in the SDK as the reference. 
The maximum read/write buffer with DMA is defined by the MAXCNT register and it's upto 65kB. In the code it's defined by UART_RX_BUF_SIZE and UART_TX_BUF_SIZE

[alex]

when I try to connect the necessary files from one example to another there are many conflicting dependencies.