CCS/TM4C1294NCPDT: Manually rpm set for drv8308 using tm4c1294ncpdt

Hi Govind,

  I will suggest you go through the PWM module in the device datasheet to be familiar with how the TM4C129 PWM works. Basically, the PWM module will have the period counter. You and pre-load the period counter with a value that determines your desired period of the PWM.  Please refer to the below snippet of example which you can also find in <TivaWare_Installation>/examples/boards/ek-tm4c1294xl/pwm_invert. Suppose you want 15000 RPM. Note this is only an example RPM. Your application determines what RPM you need. A 15000 RPM means 250Hz on the PWM period. See the below code how the PWM is configured for 250Hz. The below snippet assumes your PWM clock is 16MHz. You can program this per your application requirement to reach your desired RPM.

    //
    // Set the PWM clock to the system clock.
    //
    SysCtlPWMClockSet(SYSCTL_PWMDIV_1);

    //
    // The PWM peripheral must be enabled for use.
    //
    SysCtlPeripheralEnable(SYSCTL_PERIPH_PWM0);

    //
    // For this example PWM0 is used with PortB Pin6.  The actual port and
    // pins used may be different on your part, consult the data sheet for
    // more information.
    // GPIO port B needs to be enabled so these pins can be used.
    // TODO: change this to whichever GPIO port you are using.
    //
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB);

    //
    // Configure the GPIO pin muxing to select PWM00 functions for these pins.
    // This step selects which alternate function is available for these pins.
    // This is necessary if your part supports GPIO pin function muxing.
    // Consult the data sheet to see which functions are allocated per pin.
    // TODO: change this to select the port/pin you are using.
    //
    GPIOPinConfigure(GPIO_PB6_M0PWM0);

    //
    // Configure the PWM function for this pin.
    // Consult the data sheet to see which functions are allocated per pin.
    // TODO: change this to select the port/pin you are using.
    //
    GPIOPinTypePWM(GPIO_PORTB_BASE, GPIO_PIN_6);

    //
    // Configure the PWM0 to count up/down without synchronization.
    //
    PWMGenConfigure(PWM0_BASE, PWM_GEN_0, PWM_GEN_MODE_UP_DOWN |
                    PWM_GEN_MODE_NO_SYNC);

    //
    // Set the PWM period to 250Hz.  To calculate the appropriate parameter
    // use the following equation: N = (1 / f) * SysClk.  Where N is the
    // function parameter, f is the desired frequency, and SysClk is the
    // system clock frequency.
    // In this case you get: (1 / 250Hz) * 16MHz = 64000 cycles.  Note that
    // the maximum period you can set is 2^16.
    // TODO: modify this calculation to use the clock frequency that you are
    // using.
    //
    PWMGenPeriodSet(PWM0_BASE, PWM_GEN_0, 64000);

    //
    // Set PWM0 to a duty cycle of 25%.  You set the duty cycle as a function
    // of the period.  Since the period was set above, you can use the
    // PWMGenPeriodGet() function.  For this example the PWM will be high for
    // 25% of the time or 16000 clock ticks (64000 / 4).
    //
    PWMPulseWidthSet(PWM0_BASE, PWM_OUT_0,
                     PWMGenPeriodGet(PWM0_BASE, PWM_GEN_0) / 4);