UART problem

[pacaj2am]

Hi,

I am having problem with UART on both NRF52 Devkit nad NRF52480 dongle. If I start from the example:

nRF5_SDK_15.3.0_59ac345\examples\ble_peripheral\ble_app_uart

changing there uart parameters:

    app_uart_comm_params_t const comm_params =
    {
        .rx_pin_no    = 29,
        .tx_pin_no    = 31,
        .rts_pin_no   = NULL,
        .cts_pin_no   = NULL,
        .flow_control = APP_UART_FLOW_CONTROL_DISABLED,
        .use_parity   = false,
#if defined (UART_PRESENT)
        .baud_rate    = NRF_UART_BAUDRATE_115200
#else
        .baud_rate    = NRF_UARTE_BAUDRATE_115200
#endif
    };

shortcutting the pins and connecting with the phone nRF UART app to the device, I would expect to get back what I send to the device, but it only disconnects. Changing PINs does not help. Where is the problem with the code?

[Vidar Berg]

Hi,

This should work. Are you using Segger Embedded Studio? In that case, please select the "Debug" target from the drop-down menu in the top left corner, then start a debug session. The console window will print out error information in case there is a code assert that causes the disconnect. 

Best regards,

Vidar

[pacaj2am]

This is the output:

<error> app: ERROR 4 [NRF_ERROR_NO_MEM] at C:\nsc\my_prj\examples\ble_peripheral\my_ble_app_uart\main.c:560
PC at: 0x0002EC85
<error> app: End of error report

I am using Segger Release 4.12  Build 2018112601.37855

[Vidar Berg]

Based on the error message it looks like you are getting a framing error (UARTE.ERRORSRC). This can happen when flow control is disabled, and data is sent too fast. Please try to comment out following lines in main.c: 

case APP_UART_COMMUNICATION_ERROR:
APP_ERROR_HANDLER(p_event->data.error_communication); // invokes app error handler if p_event->data.error_communication != 0.
break;

Note: invalid UART packets will be dropped. 

[pacaj2am]

Will try that in the evening. But I ahve connected those with a jumper wire, so there should be nothing waiting there....

[steelman.kwon]

I have the same problem.
ERROR does not occur because Vidar Berg's answer is applied, but if APP_UART_COMMUNICATION_ERROR is commented out, UART RX does not work. The uart_event_handle interrupt does not occur during data transmission.
Please give me a good advice.

[Vidar Berg]

steelman.kwon, please create a new ticket where you include more details about your setup. If you always get APP_UART_COMMUNICATION_ERROR, then maybe there is a mismatch between the buadrate used on the sender and receiver?

[steelman.kwon]

Thank you for answer.
The problem I had has been resolved.
I checked and it was a different issue.
I was having a problem using NFC (pin 0.09, pin 0.10)pins as a UART pin.
Now it has been resolved.

Thank you, Vidar Berg ^^