Improve Hardware UART Speed

RE: Improve Hardware UART Speed

davidz — Tue, 23 Feb 2021 16:19:28 GMT

Thank you and this is very helpful. It is all clear now :)

RE: Improve Hardware UART Speed

Vidar Berg — Tue, 23 Feb 2021 14:25:13 GMT

No problem! 1. The buffer is limited by the size of the EasyDMA pointer, which on the nRF52840, is 16 bits long. This means that a single DMA buffer can be up to 65 kB. 2. Yes, the buffer for TX and RX is configured independently.

RE: Improve Hardware UART Speed

davidz — Mon, 22 Feb 2021 17:41:27 GMT

Thank you very much Vidar. I have two more questions:

1. How big can the UART_TX_BUF_SIZE and UART_RX_BUF_SIZE be? Is it safe to give a number of 16384 or bigger?

2. Since there is no need for me to assign a big number for the UART_RX_BUF_SIZE, can I give different buffer size to UART RX and TX? From APP_UART_FIFO_INIT definition, it looks like it is safe to do so.

RE: Improve Hardware UART Speed

Vidar Berg — Mon, 22 Feb 2021 14:42:11 GMT

Hello,

The app uart library can only send one byte at a time and thus not as efficient when you need to send larger chunks of data. I think it maybe the easiest way to improve the transfer speed is to work directly with the UART driver (UART) and set up larger transmit buffers to utilize the DMA support in UARTE.

Best regards,

Vidar