EVMK2H: how to change uart baud rate in Test project

Sherry,

Yes, the UART baudrate can absolutely be changed on this device to the required baud rate settings.  If you look at the device datasheet, you will notice that that SYSLCK /6  is used to source the UART module and inside the UART module, there is Prescalar and a oversampling factor that needs to be set to achieve a certain baudrate.

If you now look at the UART driver call UART_open_v0 call for this device, it reads in the baudrate field from the params structure to compute the prescalar using 16 bit oversampling and the provided CPU frequency(from UART_HWAttr) to set the UART module to the desired baud rate.

        /* Computing the Divisor Value for params.baudRate */
        divisorValue = UART_divisorValCompute_v0(hwAttrs->frequency,
                                                      object->params.baudRate,
                                                      UART16x_OPER_MODE);
        /* Configuring the Baud Rate settings. */
        UART_divisorLatchWrite_v0(hwAttrs->baseAddr, divisorValue);

As long as you pass the correct value of SYSCLK /6 which is the setting of the core clock as done in the board library and the GEL files. and provide the params.baudrate parameter the driver will set the UART module prescaler and oversampling to get to that baudrate. Note you will then have to set the host serial console to appropriate baudrate to communicate with the device.

Regards,

Rahul

Rahul, Thank you.
None of my functions appear to call UART_open_v0() or the divisor computations quoted above. I found this after I dug into the function calls post-build. However, I realised that UART_params_init() function call in the test project was importing the default values defined in C:\ti\pdk_k2hk_4_0_4\packages\ti\drv\uart\src\UART_drv.c

void UART_Params_init(UART_Params *params)
{

    *params = UART_defaultParams;
}

/* Default UART parameters structure */
const UART_Params UART_defaultParams = {
    UART_MODE_BLOCKING,           /* readMode */
    UART_MODE_BLOCKING,           /* writeMode */
    ...
    115200,               /* baudRate */
    ...                 /* readCallback2 */
    NULL,                 /* writeCallback2 */
};

Hence in the test project, I simply have to overwrite the variable of baudrate in the UART_Params instance just before UART_open() and just after the UART_params_init() function call (unlike doing it before UART_Params_init() that I have stated above). This saved me from changes to the GEL file or any board files. It worked.

 /* Initialize the default configuration params. */
    UART_Params_init(&uartParams);
    uartParams.baudRate = 9600;
    uart = UART_open(UART_INSTANCE, &uartParams);