How to change CC26xx/CC13xx UART baudrate dynamically in your application.

The following steps show you how to change CC26xx/CC13xx UART baudrate dynamically in your application.

1. In port pininterrupt example into your CCS.

2. Add the following header files for UART and task related stuffs.

    #include <ti/sysbios/knl/Task.h>
    #include <ti/drivers/UART.h>
    #include <stdint.h>

3. Add the following defines and global variables for UART and task related stuffs.

    #define TASKSTACKSIZE     768
    uint32_t baudrate=115200;
    bool baudrate_change=false;
    UART_Handle uart;
    UART_Params uartParams;

    Task_Struct task0Struct;
    Char task0Stack[TASKSTACKSIZE];

4. Add the following red codes into buttonCallbackFxn to change baudrate when BTN1 is pressed.

            case Board_BUTTON1:
                currVal =  PIN_getOutputValue(Board_LED1);
                PIN_setOutputValue(ledPinHandle, Board_LED1, !currVal);
                if(baudrate==115200){
                    const char echoBaudrateChange[] = "\fChange Baudrate to 9600:\r\n";
                    UART_write(uart, echoBaudrateChange, sizeof(echoBaudrateChange));
                    baudrate=9600;
                }else{
                    const char echoBaudrateChange[] = "\fChange Baudrate to 115200:\r\n";
                    UART_write(uart, echoBaudrateChange, sizeof(echoBaudrateChange));
                    baudrate=115200;
                }
                baudrate_change=true;                break;


5. Add the following function echoFxn()

Void echoFxn(UArg arg0, UArg arg1)
{
    char input;
    const char echoPrompt[] = "\fEchoing characters:\r\n";

    /* Create a UART with data processing off. */
    UART_Params_init(&uartParams);

RESTART_UART:
    uartParams.writeDataMode = UART_DATA_BINARY;
    uartParams.readDataMode = UART_DATA_BINARY;
    uartParams.readReturnMode = UART_RETURN_FULL;
    uartParams.readEcho = UART_ECHO_OFF;
    uartParams.baudRate = baudrate;
    uart = UART_open(Board_UART0, &uartParams);

    if (uart == NULL) {
        System_abort("Error opening the UART");
    }

    UART_write(uart, echoPrompt, sizeof(echoPrompt));

    /* Loop forever echoing */
    while (1) {
        if(baudrate_change){
            UART_close(uart);
            uart=NULL;
            baudrate_change=false;
            goto RESTART_UART;
        }
        UART_read(uart, &input, 1);
        UART_write(uart, &input, 1);
    }
}


6. Add the following red codes in main function to start UART task.

int main(void)
{
    Task_Params taskParams;
    /* Call board init functions */
    Board_initGeneral();
    Board_initUART();

    /* Construct BIOS objects */
    Task_Params_init(&taskParams);
    taskParams.stackSize = TASKSTACKSIZE;
    taskParams.stack = &task0Stack;
    Task_construct(&task0Struct, (Task_FuncPtr)echoFxn, &taskParams, NULL);...
}


7. Build and download firmware into LaunchPad to test it.