关于28035中断嵌套，嵌套的中断多执行了一次

user4828609

如图所示，打算使用三个中断，分别是EPWM4_ISR(90kHz), CpuTimer_ISR(10 kHz), EPWM1_ISR(200 kHz, 50%, Zero Trigger), 使其中EPWM4_ISR，CpuTimer_ISR 中都嵌套 EPWM1_ISR；当只 EPWM4_ISR 嵌套EPWM1_ISR 或只CpuTimer_ISR嵌套EPWM1_ISR，EPWM1_ISR 可正常嵌套执行；但是当EPWM4_ISR，CpuTimer_ISR，同时嵌套EPWM1_ISR时出现一个问题, EPWM1_ISR 会不时的多执行一次（图中红色箭头处）。请问为什么会这样，怎么解决这个问题？请大神指导！！！！

代码如下：
volatile Uint16 NestPIEIER;
__interrupt void epwm1_isr ( void )
{
-----------------------------------------------------------------
// Update EPWM1 & EPWM2

//---------------------------------------------------------------------
// Clear INT flag for this timer
// Acknowledge this interrupt to receive more interrupts from group 3
//---------------------------------------------------------------------
EPwm1Regs.ETCLR.bit.INT = 1;
PieCtrlRegs.PIEACK.all = PIEACK_GROUP3;

}

__interrupt void epwm4_isr(void)
{
//-------------------------------------------------------------
// Set interrupt priority:
NestPIEIER = PieCtrlRegs.PIEIER3.all;
IER |= M_INT3;
IER &= M_INT3; // Set "global" priority
PieCtrlRegs.PIEIER3.all &= 0x0001; // Set "group" priority
PieCtrlRegs.PIEACK.all = 0xFFFF; // Enable PIE interrupts
__asm(" NOP");
EINT;

//---------------------------------------------------------
// Insert ISR Code here.......
//---------------------------------------------------------

//---------------------------------------------------------------------
// Restore registers saved:
DINT;
PieCtrlRegs.PIEIER3.all = NestPIEIER;

//---------------------------------------------------------------------
// Acknowledge this interrupt to receive more interrupts from group 3
PieCtrlRegs.PIEACK.all = PIEACK_GROUP3; ///2
// Clear INT flag for this timer
EPwm4Regs.ETCLR.bit.INT = 1; ///2

}

__interrupt void CpuTimer0_isr ( void )
{
//-------------------------------------------------------------
// Set interrupt priority:
NestPIEIER = PieCtrlRegs.PIEIER3.all;
IER |= M_INT3;
IER &= M_INT3; // Set "global" priority
PieCtrlRegs.PIEIER3.all &= 0x0001; // Set "group" priority
PieCtrlRegs.PIEACK.all = 0xFFFF; // Enable PIE interrupts
__asm(" NOP");
EINT;

//---------------------------------------------------------
// Insert ISR Code here.......
//---------------------------------------------------------

//---------------------------------------------------------------------
// Restore registers saved:
DINT;
PieCtrlRegs.PIEIER3.all = NestPIEIER;

//
// Acknowledge this interrupt to receive more interrupts from group 1
//
PieCtrlRegs.PIEACK.all = PIEACK_GROUP1;
}