NRF52833 uart use 921600 baud NRF_DRV_UART_EVT_ERROR

Hi 

Could you please let me know which kind of error it is? 

Is it a FIFO error or a communication error? 

In the case of a communication error, are you able to read the value of p_event->data.error_communication?

Best regards
Torbjørn

Thanks reply!

The debug result  as shown，error_communication is 0X00000001

Hi 

Thanks for the additional details. This corresponds to the overrun error, which happens when the UART receive buffers are not updated fast enough. 

It seems very odd that this should happen after just receiving 52 bytes. 

Have you made any changes to the peripheral example, or are you just running the example out of the box?

As a general note there is a more flexible and powerful UART driver in the nRF5 SDK called nrf_libuarte, which you might also want to consider. There is an example showing how to use this in the peripheral folder. 

Best regards
Torbjørn

Hi

    For the example project, only the baud rate is modified. The nrf_libuarte test is OK.

    Can the UART project be optimized?

Hi 

I think I will have to try and reproduce the issue on my end, so I can see if there is something wrong with the example. 

If I understand you correctly all I have to do to test this is to change the baudrate to 921600, and try to send a message longer than 52 bytes to the board?

Best regards
Torbjørn

Hi 

I think I will have to try and reproduce the issue on my end, so I can see if there is something wrong with the example. 

If I understand you correctly all I have to do to test this is to change the baudrate to 921600, and try to send a message longer than 52 bytes to the board?

Best regards
Torbjørn

You might correct the baud rate divisor in use for 921600 baud, as in the nRF52833 v1.5 datasheet and SDK  v17.1.0 it is incorrect; such a big error (over 2%) can by itself accumulate to generate framing and/or overrun errors. The correct value (my calculation) is below:

// Quoted values from nRF52833 v1.5 datasheet - "No" means incorrect
//
//  --------Calculated-------------------  ---------------Documentation---------------
//  Required Register      Actual   Error  Register    Required   Actual  Error   Ok?
//  ======== =========== ======== =======  =========== ======== ======== =======  ====
//   921600, 0x0EBEE000,  921600, +0.000%  0x0F000000,  921600,  941176, +2.124%,  No,

Hi  

    I think the deviation  of baud rate can't cause the problem,because the libuarte project in example project  use 921600 baud is OK.I think the problem is caused by not receiving in time

Yes，only modify baud to 921600  and send data more than 52 byte 

Hi

Receiving more than 52 bytes seem to work fine for me, but I made some minor changes to the example to make it easier to run the test. 

Essentially I use UARTE0 for logging purposes, and enabled UARTE1 with app_uart on a separate set of pins in order to be able to print UART log info without affecting the UART under test. 

The UARTE1 interfaces is enabled with RX on pin P1.01 and TX on pin P1.02.

When sending a 53 byte string I see it all received OK in the log.

<info> app: 54 bytes received: abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz

Code below:

Best regards
Torbjørn