UART error codes

[beemavishnu]

Hello,

 

I am using nRF52840, SDK_16.0.0, SoftDevice S140 V7.0.1 and Segger for flashing the image. I am using ‘ble_app_blinky’.

 

1) I ported UART into my code and it is working fine with FDMI / UART cable connected. When I don’t connect UART cable I am getting APP_UART_COMMUNICATION_ERROR even though I did not do any Serial communications. Below is the “Call Stack”.

 

2) When will APP_UART_FIFO_ERROR occur. Is this when Rx FIFO buffer is full (NRF_ERROR_NO_MEM).

a) How about Tx buffer fill.

 

3) I further debugged and modified code as below in uart_event_handle(). I have two scenarios.

Scenario 1) Only nRF will be connected and data will be read using BLE.

Scenario 2) Other chip will be connected to nRF over UART interface and read data.

a) In Scenario 2 I am not facing issue. But in Scenario 1 I am getting 'Fatal error'. We need to use same code base in both scenarios. So to avoid this I did below modifications. Is this fine ?

b) I am getting below error. As per Product specification it is "Break condition" (8) and "Framing error occurred" (4). Even with this, if there is no serial communication will other code execute properly. Like BLE, Flash, FDS etc...

0> <info> app: Err:Com 4
0> <info> app: Err:Com 8

 case APP_UART_COMMUNICATION_ERROR:
            //APP_ERROR_HANDLER(p_event->data.error_communication);
            NRF_LOG_INFO("Err:Com %d", p_event->data.error_communication);
            break;

Thanks & Regards

Vishnu Beema

[Jared]

Hi,

It seems that there is an interrupt firing as you go into the interrupt routine handler. Are the pins that you use for UART floating when nothing is connected? 

 

So to avoid this I did below modifications. Is this fine ?

Printing out an error message is ok during the development phase but I don't think that it's a good practice for recovery for a deployed product as it doesn't recover the application. 

Jared