Data got by calling the k_fifo_get() less than the data received by the UART RX

[Tom.Fu]

Dear Support Team

I test the peripheral_uart sample from NCS(V2.4.0), I found that the data got by calling the k_fifo_get() less than the data received by the UART RX. For example, I sent 208 Bytes to the UART RX but it just printed 200 Bytes by calling the LOG_HEXDUMP_INF()  macro as the screenshots below showing, and UART baud rate I set is 921600.

Below screenshot below shows I send 208 Bytes to the RX. This packet starts with 2c and ends with 2c.

Below screenshot shows the data printed by calling the LOG_HEXDUMP_INF()  macro. It starts with 2c but ends with 77, so there was still 8 bytes haven't been printed.

Why it would loss printing the 8 bytes? How could I print all of the any size of data packet without end with \r or \n received by the UART RX?  Many thanks.

[Sigurd]

Hi,

It might not be printed until the RX buffer is full, or until timeout(https://github.com/nrfconnect/sdk-nrf/blob/main/samples/bluetooth/peripheral_uart/Kconfig#L30C8-L30C32), 50 seconds default.

Try e.g. sending 240 bytes, and see if everything is printed. or maybe try reducing CONFIG_BT_NUS_UART_RX_WAIT_TIME

[Tom.Fu]

Dear Sigurd

I configured the CONFIG_BT_NUS_UART_RX_WAIT_TIME  with value 50, it could print all the 240 bytes after PC sent 240 bytes to UART RX., but it was still loss printing the 8 bytes after PC sent 208 bytes to UART RX.

Is there any other way to get all the data of any size sent to UART RX of nRF52832? Many thanks.

[Jørgen Holmefjord]

Hi,

Tom.Fu said:

Is there any other way to get all the data of any size sent to UART RX of nRF52832? Many thanks.

The timeout should handle this, as long as the data is not sent too fast so it is lost because there is no available buffer.

If you first send 208 bytes, then 32 more bytes afterwards, are you still losing the 8 bytes?

Best regards,
Jørgen