关于EPWM中断的问题。 TKS！！1

代码如下，现在出现了一个问题，当同时采用EPWM4和EPWM1中断时，只能进入EPWM1中断；如果单独采用其中一个中断，都能进去。请哪位大神指教下。万分感谢。

EALLOW;

PieVectTable.EPWM4_INT = &EPWM4_INT_ISR; // Map CNTL Interrupt
PieCtrlRegs.PIEIER3.bit.INTx4 = 1; // PIE level enable, Grp3 / Int1, ePWM4
EPwm4Regs.CMPB = 50; // ISR trigger point
EPwm4Regs.ETSEL.bit.INTSEL = ET_CTRU_CMPB; // INT on CompareB-Up event
EPwm4Regs.ETSEL.bit.INTEN = 1; // Enable INT
EPwm4Regs.ETPS.bit.INTPRD = ET_1ST; // Generate INT on every 1st event

PieVectTable.EPWM1_INT = &EPWM1_INT_ISR; // Map PWM Interrupt
PieCtrlRegs.PIEIER3.bit.INTx1 = 1; // PIE level enable, Grp3 / Int1, ePWM1
EPwm1Regs.ETSEL.bit.INTSEL = ET_CTR_ZERO; // INT on Counter-Zero event
EPwm1Regs.ETSEL.bit.INTEN = 1; // Enable INT
EPwm1Regs.ETPS.bit.INTPRD = ET_3RD; // Generate INT on every 1st event
EDIS;