nRF9160 receives garbage data on UART sometimes

[Smitesh Mali]

Hello, 

I closed below case by mistake. 

nRF9160 receives garbage data on UART sometimes - Nordic Q&A - Nordic DevZone - Nordic DevZone (nordicsemi.com)

As per your query I am using nRF9160 DK for testing. 

I have modified "http_application_uodate" example code for my testing. 

Regards,

Smitesh Mali

[Øyvind]

Hello, 

Can you please elaborate on what you have modified on the nRF9160: HTTP application update sample? What terminal are you using to connect to the COM port? Have you tried with the nRF Connect for Desktop - LTE Link Monitor?

Kind regards,
Øyvind

[Smitesh Mali]

Hello,

Below is the interrupt routine which waits for "UUT*SIM=?\n" command from terminal. 

static void UHi_PcUartCb(const struct device *x, void* data)
{
    uart_irq_update(x);
    int data_length = 0;

    if (uart_irq_rx_ready(x)) {
            data_length = uart_fifo_read(x, &_uartPcRxChar, 1);

    }

    if (_pcCmdRxFlg)
    {
        return;
    }

    _uartPcBuf[_pcRxCntr] = _uartPcRxChar;

    if (_uartPcBuf[_pcRxCntr] == '\n')
    {
        _pcCmdRxFlg = true;
        return;
    }

    _pcRxCntr++;

}

When "\n" is receive data will be processed. 

But sometimes data received is "ª*SIM=?\n" instead of "UUT*SIM=?\n". 

Øyvind said:

What terminal are you using to connect to the COM port?

I am using "Docklight" utility in PC to communicate with com port. 

Øyvind said:

Have you tried with the nRF Connect for Desktop - LTE Link Monitor?

No, I haven't tried it. 

Regards,

Smitesh Mali

[Smitesh Mali]

I am using UART 0 to receive data from PC.

[Smitesh Mali]

Hello, 

I debugged the issue further by enabling error interrupt for UART

uart_irq_err_enable(_uartPc);

I received "UART_BREAK" (0x08) error when I get "ª*SIM=?\n" (wrong data). 

 

Interestingly, I am getting error when I receive expected data too which is "UUT*SIM=?\n". 

But at that time error is different. It is "UART_ERROR_FRAMING" (0x04) error. 

I get this error after complete data from PC is received. 

Can you tell me in what case "UART_BREAK" error can come ? 

As per the comment in "uart.h" it comes in below case. 

/**
* @brief Break interrupt
*
* A break interrupt was received. This happens when the serial input
* is held at a logic '0' state for longer than the sum of
* start time + data bits + parity + stop bits.
*/

Regards,

Smitesh Mali

[Smitesh Mali]

Hello,

Issue is resolved. 

Pin 0.28 and 0.29 were defined in overlay file for SPI. 

It was creating issue. 

UART works properly after removing it.

Regards,

Smitesh Mali