BLE_NUS_MAX_DATA_LEN and buffer size question

RE: BLE_NUS_MAX_DATA_LEN and buffer size question

Håvard — Thu, 14 Jun 2018 14:07:04 GMT

Correct, UART_TX_BUF_SIZE is only interesting if you are using the uart hardware peripheral (for example to interface a terminal on your pc), not if you are only using the Nordic UART Service to send data on air between two devices.

RE: BLE_NUS_MAX_DATA_LEN and buffer size question

Pawel Niedbala — Thu, 14 Jun 2018 12:49:18 GMT

Hi! Thanks for the answer.

So when I do use NUS service (only sending data over BLE) but I don't really want to use serial terminal and print it, I shouldn't even bother setting buffer size. Am I right?

RE: BLE_NUS_MAX_DATA_LEN and buffer size question

Vidar Berg — Thu, 14 Jun 2018 12:45:25 GMT

Hi,

UART_TX_BUF_SIZE is the SW FIFO buffer allocated to the UART interface, while BLE_NUS_MAX_DATA_LEN defines the max. data length for BLE packets as you already pointed out.

Throughput is typically higher on the UART interface compared to the BLE link so it may make sense to have a larger buffer for the UART in order to keep data while waiting for it to be transmitted over BLE.