AM437x裸机PWM发不出来

我按照ti官网提供的starware中的api函数配置EHRPWM，一直没有波形出现，请大神帮我看一下有什么不对吗？

main()
{
int32_t Prcmen_val;

uint32_t i=0;
uint32_t instNum=0U;

Prcmen_val=PRCMModuleEnable(CHIPDB_MOD_ID_PWMSS,instNum,FALSE);

if(S_PASS==Prcmen_val)
{
/********************************pin mux**********************************************************/
HW_WR_REG32((SOC_CONTROL_MODULE_REG + CTRL_CONF_SPI0_SCLK), 3U);//pwm0A

HW_WR_REG32((SOC_CONTROL_MODULE_REG + CTRL_CONF_SPI0_D0), 3U);//pwm0B
/*************************************************************************************************/

EPWMClockEnable(SOC_PWMSS0_REG);

/*********************Enable Time base clock for PWMSS module*************************************/
SOCCtrlPwmssTimebaseClkEnable(0U);

/*******************************EPWM channel configuration****************************************/
//timebase
/*******************************Configure the time base clock*************************************/
EPWMTbTimebaseClkCfg(SOC_PWMSS0_REG,10000000U,100000000U);

/*******************************Configure the output PWM frequency*************************************/

EPWMTbPwmFreqCfg(SOC_PWMSS0_REG,10000000U,20000U,EPWM_TB_COUNTER_DIR_UP,EPWM_SHADOW_REG_CTRL_ENABLE);

/*******************************configure the synchronization******************************************/

EPWMTbSyncEnable(SOC_PWMSS0_REG,3U,EPWM_TB_CNT_DIR_AFT_SYNC_UP);

/*******************************Set the sync out mode**************************************************/

EPWMTbSetSyncOutMode(SOC_PWMSS0_REG,EPWM_TB_SYNC_OUT_EVT_DISABLE);

/*******************************Set the emulation mode*************************************************/

EPWMTbSetEmulationMode(SOC_PWMSS0_REG,EPWM_TB_EMU_MODE_FREE_RUN);

//Counter comparator

EPWMCounterComparatorCfg(SOC_PWMSS0_REG,EPWM_CC_CMP_A,500U,EPWM_SHADOW_REG_CTRL_ENABLE,EPWM_CC_CMP_LOAD_MODE_CNT_EQ_PRD,TRUE);

//DeadBand

EPWMDeadbandBypass(SOC_PWMSS0_REG);

//Chopper

EPWMChopperEnable(SOC_PWMSS0_REG,FALSE);

//TripZone

EPWMTzTriggerTripAction(SOC_PWMSS0_REG,EPWM_TZ_TRIP_ACTION_HIGH,EPWM_OUTPUT_CH_A);

EPWMTzTripEventEnable(SOC_PWMSS0_REG,EPWM_TZ_EVENT_CYCLE_BY_CYCLE,1);

//Event Trigger

EPWMEtIntrDisable(SOC_PWMSS0_REG);

//HighResolution

EPWMHighResolutionCfg(SOC_PWMSS0_REG,EPWM_HR_DELAY_BUS_SEL_CMPAHR,EPWM_HR_DELAY_EDGE_CTRL_NO_DELAY);
EPWMHrLoadCmpAHrValue(SOC_PWMSS0_REG,10U,EPWM_HR_REG_ACT_LOAD_CNT_ZRO_PULSE);

while(1)
{
/* Infinite loop */
}
}

return(0);

}