TMS320F280025C: 关于ePWM模块信号同步时，会有周期性不同步

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Part Number: TMS320F280025C

利用两个epwm模块 epwm1A和 epwm2A。epwm1A设置为同步信号输出，epwm2A接收epwm1A的同步信号。当epwm1A的PRD改变时，CMA变为0.1*PRD。epwm2A的PRD跟随epwm1A变化，CMA也是0.1*PRD。而此过程，epwm1A与epwm2A的相对相移需要一直保持恒定。

正常情况如下，这是我需要的波形。注意绿色为1A，黄色为2A，后面的波形都是以此情况。

但是在运行过程中，它会周期性出现以下两种波形，这是为什么？

只有当我的PRD由小变大的时候才出现，而PRD由大变小一切正常。如下图。

代码配置如下

初始化PWM

改变PRD,CMA,PHS代码如下

1 年多前

0 Yale Li 李耀先 1 年多前

TI__Guru 65745 points

您好，您的初始化代码中，有关装载的配置只明确配置了ePWM2的周期装载时刻，我建议您将装载的时刻全部都明确配置一下试试看。

另外希望您除了上传代码截图以外，也能一并将代码通过代码插入功能上传，谢谢：

0 ? ? 1 年多前回复 Yale Li 李耀先

Prodigy 20 points

你好，非常感谢你的回复，我明确配置了EPWM1的装载方式，问题仍然存在。根据手册，利用寄存器LINK，问题也没有解决。代码如下。

//
// Included Files
//
#include "driverlib.h"
#include "device.h"
__interrupt void cpuTimer0ISR(void);
void initCPUTimers(void);
void configCPUTimer(uint32_t cpuTimer, float freq, float period);
void pin_init(void);
void init_PWM(void);
#define myEPWM1_BASE EPWM1_BASE
#define myEPWM2_BASE EPWM2_BASE
uint32_t epwm_period1 = 1000;
uint32_t epwm_compare1 = 100;
uint32_t epwm_shift = 500;
//
// Main
//
void main(void)
{
    //
    // Initializes device clock and peripherals
    //
    Device_init();
    //
    // Initializes PIE and clears PIE registers. Disables CPU interrupts.
    //
    Interrupt_initModule();
    //
    // Initializes the PIE vector table with pointers to the shell Interrupt
    // Service Routines (ISR).
    //
    Interrupt_initVectorTable();

    SysCtl_disablePeripheral(SYSCTL_PERIPH_CLK_TBCLKSYNC);
    pin_init();
    init_PWM();
    initCPUTimers();
    //
    // Configure CPU-Timer 0,
    //
    configCPUTimer(CPUTIMER0_BASE, DEVICE_SYSCLK_FREQ, 100);
    SysCtl_enablePeripheral(SYSCTL_PERIPH_CLK_TBCLKSYNC);
    //
    // ISRs for each CPU Timer interrupt
    //
    Interrupt_register(INT_TIMER0, &cpuTimer0ISR);
    //
    // Enables CPU int1 which are connected to CPU-Timer 0.
    // Enable TINT0 in the PIE: Group 1 interrupt 7
    //
    Interrupt_enable(INT_TIMER0);
    //
    // Starts CPU-Timer 0.
    //
    CPUTimer_startTimer(CPUTIMER0_BASE);
    //
    // Enable Global Interrupt (INTM) and realtime interrupt (DBGM)
    //
    EINT;
    ERTM;
    while(1)
    {


    }
}
__interrupt void
cpuTimer0ISR(void)
{
    if(epwm_period1 == 1000)
    {
        epwm_period1 = 100;
        epwm_compare1 = 10;
        epwm_shift = 50;
        //updata epwm1 and epwm2 CMA
        HWREG(0X0000406B)=epwm_compare1;
        HWREG(0X0000416B)=epwm_compare1;
        //updata epwm1 and epwm2 PRD
        HWREG(0X00004063)=epwm_period1;
        HWREG(0X00004163)=epwm_period1;
        //updata epwm2 PHS
        HWREG(0X00004161)=epwm_shift;
    }
    else if(epwm_period1 == 100)
    {
        epwm_period1 = 1000;
        epwm_compare1 = 100;
        epwm_shift = 500;


        //updata epwm1 and epwm2 PRD
        HWREG(0X00004063)=epwm_period1;
        HWREG(0X00004163)=epwm_period1;
        //updata epwm1 and epwm2 CMA
        HWREG(0X0000406B)=epwm_compare1;
        HWREG(0X0000416B)=epwm_compare1;
        //updata epwm2 PHS
        HWREG(0X00004161)=epwm_shift;
    }
    //
    // Acknowledge this interrupt to receive more interrupts from group 1
    //
    Interrupt_clearACKGroup(INTERRUPT_ACK_GROUP1);
}

void
initCPUTimers(void)
{
    //
    // Initialize timer period to maximum
    //
    CPUTimer_setPeriod(CPUTIMER0_BASE, 0xFFFFFFFF);


    //
    // Initialize pre-scale counter to divide by 1 (SYSCLKOUT)
    //
    CPUTimer_setPreScaler(CPUTIMER0_BASE, 0);


    //
    // Make sure timer is stopped
    //
    CPUTimer_stopTimer(CPUTIMER0_BASE);

    //
    // Reload all counter register with period value
    //
    CPUTimer_reloadTimerCounter(CPUTIMER0_BASE);


}
void
configCPUTimer(uint32_t cpuTimer, float freq, float period)
{
    uint32_t temp;

    //
    // Initialize timer period:
    //
    temp = (uint32_t)((freq / 1000000) * period);
    CPUTimer_setPeriod(cpuTimer, temp);

    //
    // Set pre-scale counter to divide by 1 (SYSCLKOUT):
    //
    CPUTimer_setPreScaler(cpuTimer, 0);

    //
    // Initializes timer control register. The timer is stopped, reloaded,
    // free run disabled, and interrupt enabled.
    // Additionally, the free and soft bits are set
    //
    CPUTimer_stopTimer(cpuTimer);
    CPUTimer_reloadTimerCounter(cpuTimer);
    CPUTimer_setEmulationMode(cpuTimer,
                              CPUTIMER_EMULATIONMODE_STOPAFTERNEXTDECREMENT);
    CPUTimer_enableInterrupt(cpuTimer);


}
void init_PWM(void)
{
    EPWM_setClockPrescaler(myEPWM1_BASE, EPWM_CLOCK_DIVIDER_1, EPWM_HSCLOCK_DIVIDER_1);
    EPWM_setTimeBasePeriod(myEPWM1_BASE, 1000);
    EPWM_setPeriodLoadMode(myEPWM1_BASE, EPWM_PERIOD_SHADOW_LOAD);
    EPWM_selectPeriodLoadEvent(myEPWM1_BASE, EPWM_SHADOW_LOAD_MODE_COUNTER_ZERO);
    EPWM_setTimeBaseCounter(myEPWM1_BASE, 0);
    EPWM_setTimeBaseCounterMode(myEPWM1_BASE, EPWM_COUNTER_MODE_UP);
    EPWM_disablePhaseShiftLoad(myEPWM1_BASE);
    EPWM_setPhaseShift(myEPWM1_BASE, 0);
    EPWM_enableSyncOutPulseSource(myEPWM1_BASE, EPWM_SYNC_OUT_PULSE_ON_CNTR_ZERO);
    EPWM_setCounterCompareValue(myEPWM1_BASE, EPWM_COUNTER_COMPARE_A, 500);
    EPWM_setCounterCompareShadowLoadMode(myEPWM1_BASE, EPWM_COUNTER_COMPARE_A, EPWM_COMP_LOAD_ON_CNTR_ZERO);
    EPWM_setCounterCompareValue(myEPWM1_BASE, EPWM_COUNTER_COMPARE_B, 500);
    EPWM_setCounterCompareShadowLoadMode(myEPWM1_BASE, EPWM_COUNTER_COMPARE_B, EPWM_COMP_LOAD_ON_CNTR_ZERO);
    EPWM_setActionQualifierAction(myEPWM1_BASE, EPWM_AQ_OUTPUT_A, EPWM_AQ_OUTPUT_HIGH, EPWM_AQ_OUTPUT_ON_TIMEBASE_ZERO);
    EPWM_setActionQualifierAction(myEPWM1_BASE, EPWM_AQ_OUTPUT_A, EPWM_AQ_OUTPUT_LOW, EPWM_AQ_OUTPUT_ON_TIMEBASE_UP_CMPA);
    EPWM_setActionQualifierAction(myEPWM1_BASE, EPWM_AQ_OUTPUT_B, EPWM_AQ_OUTPUT_HIGH, EPWM_AQ_OUTPUT_ON_TIMEBASE_ZERO);
    EPWM_setActionQualifierAction(myEPWM1_BASE, EPWM_AQ_OUTPUT_B, EPWM_AQ_OUTPUT_LOW, EPWM_AQ_OUTPUT_ON_TIMEBASE_UP_CMPB);

    EPWM_setClockPrescaler(myEPWM2_BASE, EPWM_CLOCK_DIVIDER_1, EPWM_HSCLOCK_DIVIDER_1);
    EPWM_setTimeBasePeriod(myEPWM2_BASE, 1000);
    EPWM_setPeriodLoadMode(myEPWM2_BASE, EPWM_PERIOD_SHADOW_LOAD);
    EPWM_selectPeriodLoadEvent(myEPWM2_BASE, EPWM_SHADOW_LOAD_MODE_COUNTER_SYNC);
    EPWM_setTimeBaseCounter(myEPWM2_BASE, 0);
    EPWM_setTimeBaseCounterMode(myEPWM2_BASE, EPWM_COUNTER_MODE_UP);
    EPWM_enablePhaseShiftLoad(myEPWM2_BASE);
    EPWM_setPhaseShift(myEPWM2_BASE, 500);
    EPWM_setSyncInPulseSource(myEPWM2_BASE, EPWM_SYNC_IN_PULSE_SRC_SYNCOUT_EPWM1);
    EPWM_setCounterCompareValue(myEPWM2_BASE, EPWM_COUNTER_COMPARE_A, 500);
    EPWM_setCounterCompareShadowLoadMode(myEPWM2_BASE, EPWM_COUNTER_COMPARE_A, EPWM_COMP_LOAD_ON_CNTR_ZERO);
    EPWM_setCounterCompareValue(myEPWM2_BASE, EPWM_COUNTER_COMPARE_B, 500);
    EPWM_setCounterCompareShadowLoadMode(myEPWM2_BASE, EPWM_COUNTER_COMPARE_B, EPWM_COMP_LOAD_ON_CNTR_ZERO);
    EPWM_setActionQualifierAction(myEPWM2_BASE, EPWM_AQ_OUTPUT_A, EPWM_AQ_OUTPUT_HIGH, EPWM_AQ_OUTPUT_ON_TIMEBASE_ZERO);
    EPWM_setActionQualifierAction(myEPWM2_BASE, EPWM_AQ_OUTPUT_A, EPWM_AQ_OUTPUT_LOW, EPWM_AQ_OUTPUT_ON_TIMEBASE_UP_CMPA);
    EPWM_setActionQualifierAction(myEPWM2_BASE, EPWM_AQ_OUTPUT_B, EPWM_AQ_OUTPUT_HIGH, EPWM_AQ_OUTPUT_ON_TIMEBASE_ZERO);
    EPWM_setActionQualifierAction(myEPWM2_BASE, EPWM_AQ_OUTPUT_B, EPWM_AQ_OUTPUT_LOW, EPWM_AQ_OUTPUT_ON_TIMEBASE_UP_CMPB);

}
void pin_init(void)
{
    GPIO_setPinConfig(GPIO_0_EPWM1_A);
    GPIO_setPinConfig(GPIO_1_EPWM1_B);

    GPIO_setPinConfig(GPIO_2_EPWM2_A);
    GPIO_setPinConfig(GPIO_3_EPWM2_B);


}
//
// End of File
//

0 Yale Li 李耀先 1 年多前回复 ? ?

TI__Guru 65745 points

方便发下您的工程吗？我看下

0 ? ? 1 年多前回复 Yale Li 李耀先

Prodigy 20 points

Yale LI,你好。你将我发的代码放入tms320f28002x的空工程就好啦。将代码拷贝，粘帖到empty_projectmain.c中即可。要使用drverlib哈。我使用的是2820025c ladpad.

0 Yale Li 李耀先 1 年多前回复 ? ?

TI__Guru 65745 points

好的，我看一下

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TMS320F280025C: 关于ePWM模块信号同步时，会有周期性不同步