[参考译文] TMS320F280049C：具有死区的固定占空比

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https://e2e.ti.com/support/microcontrollers/c2000-microcontrollers-group/c2000/f/c2000-microcontrollers-forum/1429080/tms320f280049c-fixed-duty-cycle-with-deadband

器件型号：TMS320F280049C

工具与软件：

您好！

我将尝试生成2个反相 PWM、每个 PWM 具有50%的占空比、并且信号之间有一个200ns 的死区、因此将正确生成死区

但我的问题是、我无法获得精确的占空比值、如示波器 pic 中所示、占空比在47%- 53%之间变化。设置
那么,我如何在保持死区的同时实现精确的占空比(精确的50 %)(代码是)

#include "f28x_Project.h"

__interrupt void epwm1_ISR(void);
__interrupt void epwm2_ISR(void);

//PWM Period= (2×Desired Frequency) / System Clock


Uint16 pwm_period = 333;  // 150 kHz frequency with 100 MHz clock
Uint16 duty_cycle_cmpa = 166;  // 50% duty cycle (TBPRD/2)
Uint16 deadband_value = 20;  // 200 ns deadband (20 clock cycles)

void main(void)
{
    // Initialize system

    InitSysCtrl();

    // Disable interrupts
    DINT;

    // Clear interrupts
    IER = 0x0000;
    IFR = 0x0000;

    // Initialize peripherals
    InitPieCtrl();

    // Initialize PIE vector table
    InitPieVectTable();

    // Assign our ISR addresses to the elements in vector table
    EALLOW;
    PieVectTable.EPWM1_INT = &epwm1_ISR;
    PieVectTable.EPWM2_INT = &epwm2_ISR;
    EDIS;

    // Enable ePWM1 and ePWM2 clocks
    EALLOW;
    CpuSysRegs.PCLKCR2.bit.EPWM1 = 1;
    CpuSysRegs.PCLKCR2.bit.EPWM2 = 1;
    EDIS;

    // Configure ePWM1
    EPwm1Regs.TBPRD = pwm_period;  // Set 150 kHz period
    EPwm1Regs.TBCTL.bit.CTRMODE = 2;  // Up-down count mode
    EPwm1Regs.TBCTL.bit.HSPCLKDIV = 0;  // No high-speed clock divider
    EPwm1Regs.TBCTL.bit.CLKDIV = 0;  // No clock divider

    EPwm1Regs.CMPA.bit.CMPA = pwm_period/2;  // 50% duty cycle

    // Configure Action Qualifier for ePWM1 A and B
    EPwm1Regs.AQCTLA.bit.CAU = AQ_CLEAR;  // Clear PWM on CMPA up count
    EPwm1Regs.AQCTLA.bit.CAD = AQ_SET;    // Set PWM on CMPA down count

    EPwm1Regs.AQCTLB.bit.CAU = AQ_CLEAR;    // Set PWM on CMPA up count
    EPwm1Regs.AQCTLB.bit.CAD = AQ_SET;  // Clear PWM on CMPA down count

    // Dead band configuration for ePWM1
    EPwm1Regs.DBCTL.bit.IN_MODE = 1;  // EPWMxA as source for both rising and falling edges
    EPwm1Regs.DBCTL.bit.POLSEL = 2;   // Active low complementary mode
    EPwm1Regs.DBCTL.bit.OUT_MODE = 3; // Deadband fully enabled
    EPwm1Regs.DBRED.bit.DBRED = deadband_value; // Rising edge delay
    EPwm1Regs.DBFED.bit.DBFED = deadband_value; // Falling edge delay

    // Configure ePWM2 similarly
    EPwm2Regs.TBPRD = pwm_period;
    EPwm2Regs.TBCTL.bit.CTRMODE = 2;  // Up-down count mode
    EPwm2Regs.TBCTL.bit.HSPCLKDIV = 0;
    EPwm2Regs.TBCTL.bit.CLKDIV = 0;

    EPwm2Regs.CMPA.bit.CMPA = pwm_period/2;  // 50% duty cycle

    EPwm2Regs.AQCTLA.bit.CAU = AQ_CLEAR;
    EPwm2Regs.AQCTLA.bit.CAD = AQ_SET;

    EPwm2Regs.AQCTLB.bit.CAU = AQ_CLEAR;
    EPwm2Regs.AQCTLB.bit.CAD = AQ_SET;

    // Dead band configuration for ePWM2
    EPwm2Regs.DBCTL.bit.IN_MODE = 1;
    EPwm2Regs.DBCTL.bit.POLSEL = 2;
    EPwm2Regs.DBCTL.bit.OUT_MODE = 3;
    EPwm2Regs.DBRED.bit.DBRED = deadband_value;
    EPwm2Regs.DBFED.bit.DBFED = deadband_value;

    // Enable PIE interrupts for ePWM1 and ePWM2
    PieCtrlRegs.PIEIER3.bit.INTx1 = 1;
    PieCtrlRegs.PIEIER3.bit.INTx2 = 1;

    // Enable group interrupts in IER
    IER |= M_INT3;

    // Enable global interrupts
    EINT;

    // Setup GPIO pins for ePWM1 and ePWM2
    EALLOW;
    GpioCtrlRegs.GPAMUX1.bit.GPIO0 = 1;  // ePWM1A
    GpioCtrlRegs.GPAMUX1.bit.GPIO1 = 1;  // ePWM1B
    GpioCtrlRegs.GPAMUX1.bit.GPIO2 = 1;  // ePWM2A
    GpioCtrlRegs.GPAMUX1.bit.GPIO3 = 1;  // ePWM2B
    EDIS;

    // Infinite loop
    for (;;);
}

// ISR for ePWM1
__interrupt void epwm1_ISR(void)
{
    // Clear interrupt flag
    EPwm1Regs.ETCLR.bit.INT = 1;
    // Acknowledge interrupt in PIE
    PieCtrlRegs.PIEACK.bit.ACK3 = 1;
}

// ISR for ePWM2
__interrupt void epwm2_ISR(void)
{
    // Clear interrupt flag
    EPwm2Regs.ETCLR.bit.INT = 1;
    // Acknowledge interrupt in PIE
    PieCtrlRegs.PIEACK.bit.ACK3 = 1;
}