MSP432P401R: High Speed timer for PWM

Hello,

The following is an adaptation from the example found here:

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/*******************************************************************************
 * MSP432 Timer_A - Variable PWM
 *
 * Description: In this example, the Timer_A module is used to create a precision 
 * PWM with 50% duty cycle
 *
 *                MSP432P401
 *             ------------------
 *         /|\|                  |
 *          | |                  |
 *          --|RST           |
 *            |                  |
 *            |                  |
 *            |            P2.4  |--> Output PWM
 *            |                  |
 *            |                  |
 *
 *******************************************************************************/
/* DriverLib Includes */
#include <ti/devices/msp432p4xx/driverlib/driverlib.h>

/* Standard Includes */
#include <stdint.h>
#include <stdbool.h>

//![Simple Timer_A Config]
/* Timer_A PWM Configuration Parameter */
Timer_A_PWMConfig pwmConfig =
{
        TIMER_A_CLOCKSOURCE_SMCLK,
        TIMER_A_CLOCKSOURCE_DIVIDER_1,
        95,  //  24Mhz/(N+1) = 250k
        TIMER_A_CAPTURECOMPARE_REGISTER_1,
        TIMER_A_OUTPUTMODE_RESET_SET,
        48   // 50% duty cycle
};
//![Simple Timer_A Config]

int main(void)
{
    /* Halting the watchdog */
    MAP_WDT_A_holdTimer();

    //![Simple Timer_A Example]
    /*
     * Revision C silicon supports wait states of 1 at 48Mhz
     */
    MAP_PCM_setCoreVoltageLevel(PCM_VCORE1);
    MAP_FlashCtl_setWaitState(FLASH_BANK0, 1);
    MAP_FlashCtl_setWaitState(FLASH_BANK1, 1);

    /*
     * Setting up clocks
     * MCLK = MCLK = 48MHz
     * SMCLK = MCLK/2 = 24Mhz
     * ACLK = REFO = 32Khz
     */
    MAP_CS_setDCOFrequency(48000000);
    MAP_CS_initClockSignal(CS_ACLK, CS_REFOCLK_SELECT, CS_CLOCK_DIVIDER_1);
    MAP_CS_initClockSignal(CS_SMCLK, CS_DCOCLK_SELECT, CS_CLOCK_DIVIDER_2);
    MAP_CS_initClockSignal(CS_MCLK, CS_DCOCLK_SELECT, CS_CLOCK_DIVIDER_1);
    /* Configuring GPIO2.4 as peripheral output for PWM  */
    MAP_GPIO_setAsPeripheralModuleFunctionOutputPin(GPIO_PORT_P2, GPIO_PIN4,
            GPIO_PRIMARY_MODULE_FUNCTION);
    MAP_Timer_A_generatePWM(TIMER_A0_BASE, &pwmConfig);
    //![Simple Timer_A Example]
    /* Sleeping when not in use */
    while (1)
    {
        MAP_PCM_gotoLPM0();
    }
}

Regards,

Chris

Sorry, I forgot to mention that if you want to use the external crystal then setup the clocks as follows:

CS_setExternalClockSourceFrequency(32000,48000000);
hfxtResult = CS_startHFXTWithTimeout(false,100000);
if(hfxtResult == true)
{
  /* Initializing MCLK to HFXT (effectively 48MHz) */
  MAP_CS_initClockSignal(CS_ACLK, CS_REFOCLK_SELECT, CS_CLOCK_DIVIDER_1);
  MAP_CS_initClockSignal(CS_SMCLK, CS_HFXTCLK_SELECT, CS_CLOCK_DIVIDER_2);
  MAP_CS_initClockSignal(CS_MCLK, CS_HFXTCLK_SELECT, CS_CLOCK_DIVIDER_1);
  //![Simple CS Config]
}
else
{
  while(1); // HFXT failed
}

Regards,
Chris

Danny,

The application is a 5 color LED dimmer controller.  I understand that running the ISR that fast will occupy much of the processor time.  But that ISR is the priority of what the controller does for this application.

So please let me know, can the TA1_0_IRQHandler ISR operate at 250kHz and what are the settings to achieve that?  I have a working prototype that is operating at about 66kHz now. 

Thank you for your assistance,

Christian

Excellent.  This is very good suggestion.  The 4 PWMs for each Timer sounds like the solution. 

I am out of town for the week, and I will try this as soon as I return.

Thank you,  Christian