How much the largest value of UART_TX_BUF_SIZE can be set?

[helen]

Hi

I want to use app_uart_put() to send an array which is over 4096 bytes.I try to change the value of UART_TX_BUF_SIZE to 10K bytes，then call the app_uart_put() to send an array which size is 10k bytes ，but fail.Can the app_uart_put() send an array which size is 10k bytes?

[Lukas_Simma]

Hi helen

Only an idea:
Have you enabled Logging for the UART modules?
Inside the TX function I see a HEX dump LOG statement.
This HEX dump reserves much space (tx_buffer_size * 4bytes) ....

Disable logging and try again....

Best regards,
Lukas

[helen]

Hi

       The version of SDK is v15.3，The example is ble_app_uart_c ，There is not a NRF_LOG_BACKEND_UART_ENABLED in the sdk_config.h.I think that the logging for the uart doesn‘t enable.Is there any other way for me to try?

[Einar Thorsrud]

Hi,

I assume you got NRF_ERROR_INVALID_LENGTH from APP_UART_FIFO_INIT()? You will get that if the buffer size is not a power of two. As long as it is, the only other requirement is that you have enough memory. That means that the smallest supported buffer that is larger than 10kB is 2^14 = 16384. With that, it should work.