CC2652P7: UART bytes written and buffer length don't match

Hello Karthik,

Please provide additional information:

• Can you replicate this behavior with LP-CC1352P7-4 hardware?
• Are you operating a RF stack solution consecutively?
• Is there an error code returned from UART2_write?
• Can you connect the UART TX line to an oscilloscope or logic analyzer to further evaluate what bytes are being transmitted?
• Does the bytes actually written scale with the length of bytes you intend to send (i.e. is there always a disparity of 9 bytes)? 

Regards,
Ryan

Hi Ryan,

Here are the inline replies:

(2) Custom RF stack in syscfg.

(3) No error code.

(5) There is no such pattern of 9 bytes thing. The 'bytesWritten' is always seen as 50 bytes while the 'len' increased. The more parameters I add to print statement, there is trouble. Looks like data gets chopped.

Also, the UART baud is 230400. Tried with lower baud rates too but no use.

Thanks

Karthik

Please provide code snippets, or a simplified application file, that you know will replicate the issue.

Regards,
Ryan

Here it is:

The following printf runs in a loop of 4 iterations.

uart_printf("\n\r\t:%d:%d:%d:%d:%d:%d:%d:%d:%d:%d:%d:%d:%d:%d:%d:%d:%d:%d:%d:%d:%d:\n\r\xff",
                                                                    radio,
                                                                    lastPacket[radio].len,
                                                                    //lastPacket[radio].lastSeqNo,
                                                                    lastPacket[radio].seqNo,
                                                                    rxPktCount[radio],
                                                                    otherPktCount[radio],
                                                                    crcErrorCount[radio],
                                                                    pristinePktCount[radio],
                                                                    noiseInPktCount[radio],
                                                                    noiseOutPktCount[radio],
                                                                    reflectionInPktCount[radio],
                                                                    reflectionOutPktCount[radio],
                                                                    interferenceInPktCount[radio],
                                                                    interferenceOutPktCount[radio],
                                                                    obstructionInPktCount[radio],
                                                                    obstructionOutPktCount[radio],
                                                                    lastPacket[radio].rssi,
                                                                    lastPacket[radio].lqi,
                                                                    lastPacket[radio].syncDelta,
                                                                    lastPacket[radio].missedAcks,
                                                                    (channel_number_table_last[radio] - 11)*5 + 2405,
                                                                    lastASN);

void uart_printf(const char *format, ...)
{
    va_list args;
    va_start(args, format);

    char buffer[128]; // Adjust buffer size as needed
    vsnprintf(buffer, sizeof(buffer), format, args);

    va_end(args);

    uart_send_data((const uint8_t *)buffer, strlen(buffer));
}

void uart_send_data(const uint8_t *data, uint32_t len)
{
    size_t bytesWritten = 0;
    int16_t return_status;
    return_status = UART2_write(uart, data, len,&bytesWritten);

    //Karts[15-02-2024]: error handling
    if(return_status == UART2_STATUS_EINUSE)
    {
        uart_printf("\n uart error UART2_STATUS_EINUSE \n\r");
        while(1);
    }
    else
    {
        ;
    }
}

Thanks

Karthik

Hi Karthik,

You should debug uart_send_data at UART2_write to ensure that the parameters are always correct and have not been incorrectly altered by vsnprintf.  You have also displayed an incomplete monitoring of the return status, as many more are available.  Also monitor the value of bytesWritten to see if it matches your expectations.  Please determine whether using uart_printf with a single parameter which contains >50 bytes (i.e. string) displays similar behavior.  To save time and work around your current problem, you could simply expand uart_printf into multiple calls with less parameters of each.

Regards,
Ryan

Hi Ryan,

The bytesWritten is always 50.

Example with string greater than 50 byes:

uart_printf("\r\n qwertyuiopasdfghjklzxcvbnmqwertyuiopasdfghjklzxcvbnm");

Please see the snapshot:

Thanks

Karthik