求助！！！DCAEVT1.sync 同步EPWM时EPWM1A异常，存在小电压脉冲

以下是我的程序：

#include "math.h"
#include "DSP28x_Project.h" // Device Headerfile and Examples Include File

volatile Uint16 Ton = 360; //define on time，稳定工作时Ton=950
Uint16 Tdelay = 180; //还要减小

void InitEPwm1Example(void); //Configure ePWM module

int main(void) {

InitSysCtrl(); // Initialize System Control

InitGpio(); //Initialize GPIO

InitEPwm1Gpio(); //PWM1_L

InitTzGpio();

//Configure ePWM module
EALLOW;
SysCtrlRegs.PCLKCR0.bit.TBCLKSYNC = 0;

InitEPwm1Example();

SysCtrlRegs.PCLKCR0.bit.TBCLKSYNC = 1;
EDIS;

//wait for timer0 interrupt
for(;;);
}

void InitEPwm1Example(){

// Setup TBCLK
EPwm1Regs.TBCTL.bit.CTRMODE = TB_COUNT_UP; // Count up
EPwm1Regs.TBPRD = 9000; // Set timer period
EPwm1Regs.TBCTL.bit.PHSEN = TB_ENABLE; // Enable phase loading
EPwm1Regs.TBPHS.half.TBPHS = 0; // Phase is 0
EPwm1Regs.TBCTR = 0x0000; // Clear counter
EPwm1Regs.TBCTL.bit.HSPCLKDIV = TB_DIV1; // Clock ratio to SYSCLKOUT
EPwm1Regs.TBCTL.bit.CLKDIV = TB_DIV1;

// Setup shadow register load on ZERO
EPwm1Regs.CMPCTL.bit.SHDWAMODE = CC_SHADOW;
EPwm1Regs.CMPCTL.bit.SHDWBMODE = CC_SHADOW;
EPwm1Regs.CMPCTL.bit.LOADAMODE = CC_CTR_ZERO;
EPwm1Regs.CMPCTL.bit.LOADBMODE = CC_CTR_ZERO;

// Set Compare values
EPwm1Regs.CMPA.half.CMPA = Ton+Tdelay; // Set compare A value
EPwm1Regs.CMPB = Tdelay; // Set Compare B value

// Set Actions
EPwm1Regs.AQCTLB.bit.CBU = AQ_SET; // Set PWM1A on Zero
EPwm1Regs.AQCTLB.bit.CAU = AQ_CLEAR; // Clear PWM1A on event A, up count

// EPwm1Regs.AQCTLA.bit.CBU = AQ_CLEAR; // Set PWM1B on Zero
// EPwm1Regs.AQCTLA.bit.CAU = AQ_SET; // Clear PWM1B on event B, up count

EPwm1Regs.DCTRIPSEL.bit.DCAHCOMPSEL = 0x1; // DCAH = TZ2
EPwm1Regs.TZDCSEL.bit.DCAEVT1 = 0x2; // DCAEVT1 = DCAH high, DCAL don't care;
EPwm1Regs.DCACTL.bit.EVT1SRCSEL = 0x0; // 0 Source Is DCAEVT1 Signal； 1 Source Is DCEVTFILT Signal；
EPwm1Regs.DCACTL.bit.EVT1SYNCE = 0x1; // Take sync path

}

以上程序在LAUNCHXL-F28069M上运行的结果如下。下图是示波器观测的波形，从上往下依次是TZ2（绿色），EPWM1A（深蓝），EPWM1B（浅蓝），可见EPWM1A出现异常现象，没有稳定在0电平，而是有一个1V左右的脉冲。

而注释掉以上程序最后四句关于DC模块的配置，输出波形正常，如下

希望能有大牛帮忙解答这个问题。由于这个异常现象，我无法配置一个EPWM去控制一个桥臂，耽误了项目进度。

PS：我更换过DSP板，供电方式，EPWM2和EPWM3都存在这个问题。