TMS320F28379D: PWM Deadband question.

Bae Su-min,

Here is some code you can use to test out different DB values with the setup you have. I only coded one output (EPWM2) but you can always just configure more outputs to call the setupEPWMActiveHighComplementary(base) function and maybe pass in the DB value as an input parameter.

//
// Included Files
//
#include "driverlib.h"
#include "device.h"
#include "board.h"

#define EPWM_TIMER_TBPRD    250UL

//
// Function Prototypes
//
void initEPWMWithoutDB(uint32_t base);
void setupEPWMActiveHighComplementary(uint32_t base);

void main(void)
{

    //
    // Initialize device clock and peripherals
    //
    Device_init();

    //
    // Disable pin locks and enable internal pull-ups.
    //
    Device_initGPIO();

    //
    // Initialize PIE and clear PIE registers. Disables CPU interrupts.
    //
    Interrupt_initModule();

    //
    // Initialize the PIE vector table with pointers to the shell Interrupt
    // Service Routines (ISR).
    //
    Interrupt_initVectorTable();

    //
    // Configure ePWMs
    //
    Board_init();

    //
    // Disable sync(Freeze clock to PWM as well). GTBCLKSYNC is applicable
    // only for multiple core devices. Uncomment the below statement if
    // applicable.
    //
    // SysCtl_disablePeripheral(SYSCTL_PERIPH_CLK_GTBCLKSYNC);
    SysCtl_disablePeripheral(SYSCTL_PERIPH_CLK_TBCLKSYNC);

    //
    // Initialize ePWM1
    //
    initEPWMWithoutDB(myEPWM1_BASE);

    //
    // Initialize ePWM2 Active High
    //
    initEPWMWithoutDB(myEPWM2_BASE);
    setupEPWMActiveHighComplementary(myEPWM2_BASE);

    //
    // Enable sync and clock to PWM
    //
    SysCtl_enablePeripheral(SYSCTL_PERIPH_CLK_TBCLKSYNC);


    //
    // Enable Global Interrupt (INTM) and real time interrupt (DBGM)
    //
    EINT;
    ERTM;

    //
    // IDLE loop. Just sit and loop forever (optional):
    //
    for(;;)
    {
        NOP;
    }
}


void setupEPWMActiveHighComplementary(uint32_t base)
{
    //
    // Use EPWMA as the input for RED
    // Use EPWMB as the input for FED
    //
    EPWM_setRisingEdgeDeadBandDelayInput(base, EPWM_DB_INPUT_EPWMA);
    EPWM_setFallingEdgeDeadBandDelayInput(base, EPWM_DB_INPUT_EPWMB);

    //
    // Set the RED and FED values
    //
    EPWM_setFallingEdgeDelayCount(base, 200);
    EPWM_setRisingEdgeDelayCount(base, 200);

    //
    // Invert only the Falling Edge delayed output (AHC)
    //
    EPWM_setDeadBandDelayPolarity(base, EPWM_DB_RED, EPWM_DB_POLARITY_ACTIVE_HIGH);
    EPWM_setDeadBandDelayPolarity(base, EPWM_DB_FED, EPWM_DB_POLARITY_ACTIVE_LOW);

    //
    // Use the delayed signals instead of the original signals
    //
    EPWM_setDeadBandDelayMode(base, EPWM_DB_RED, true);
    EPWM_setDeadBandDelayMode(base, EPWM_DB_FED, true);

    //
    // DO NOT Switch Output A with Output B
    //
    EPWM_setDeadBandOutputSwapMode(base, EPWM_DB_OUTPUT_A, false);
    EPWM_setDeadBandOutputSwapMode(base, EPWM_DB_OUTPUT_B, false);

}


//
// initEPWM - Configure ePWM1
//
void initEPWMWithoutDB(uint32_t base)
{
    //
    // Set-up TBCLK
    //
    EPWM_setTimeBasePeriod(base, EPWM_TIMER_TBPRD);
    EPWM_setPhaseShift(base, 0U);
    EPWM_setTimeBaseCounter(base, 0U);
    EPWM_setTimeBaseCounterMode(base, EPWM_COUNTER_MODE_UP_DOWN);
    EPWM_disablePhaseShiftLoad(base);

    //
    // Set ePWM clock pre-scaler
    //
    EPWM_setClockPrescaler(base,
                           EPWM_CLOCK_DIVIDER_4,
                           EPWM_HSCLOCK_DIVIDER_4);

    //
    // Set up shadowing
    //
    EPWM_setCounterCompareShadowLoadMode(base,
                                         EPWM_COUNTER_COMPARE_A,
                                         EPWM_COMP_LOAD_ON_CNTR_ZERO);

    //
    // Set-up compare
    //
    EPWM_setCounterCompareValue(base, EPWM_COUNTER_COMPARE_A, EPWM_TIMER_TBPRD-100);
    EPWM_setCounterCompareValue(base, EPWM_COUNTER_COMPARE_B, EPWM_TIMER_TBPRD-100);

    //
    // Set actions
    //
    EPWM_setActionQualifierAction(base,
                                      EPWM_AQ_OUTPUT_A,
                                      EPWM_AQ_OUTPUT_HIGH,
                                      EPWM_AQ_OUTPUT_ON_TIMEBASE_UP_CMPA);
    EPWM_setActionQualifierAction(base,
                                      EPWM_AQ_OUTPUT_A,
                                      EPWM_AQ_OUTPUT_LOW,
                                      EPWM_AQ_OUTPUT_ON_TIMEBASE_DOWN_CMPA);
    //
    // Set actions
    //
    EPWM_setActionQualifierAction(base,
                                      EPWM_AQ_OUTPUT_B,
                                      EPWM_AQ_OUTPUT_HIGH,
                                      EPWM_AQ_OUTPUT_ON_TIMEBASE_UP_CMPA);
    EPWM_setActionQualifierAction(base,
                                      EPWM_AQ_OUTPUT_B,
                                      EPWM_AQ_OUTPUT_LOW,
                                      EPWM_AQ_OUTPUT_ON_TIMEBASE_DOWN_CMPA);

}

Best Regards,

Marlyn