tms320f28335: Interrupt disable / re-enable

Hi I am running two interrupts: 1) INT13 for SPI and CAN and 2)INT3.3 for Control (time critical). INT13 is nested wrt to INT3.1, that is INT3.1 can interrupt INT13_ISR (my understanding from http://processors.wiki.ti.com/index.php/Interrupt_Nesting_on_C28x

main(void)

{

InitSysCtrl();

DisableDog();

DINT;

InitPieCtrl();

IER = 0x0000;

IFR = 0x0000;

InitPieVectTable();

EALLOW; // This is needed to write to EALLOW protected registers

PieVectTable.EPWM1_INT = &epwm1_timer_isr;

PieVectTable.XINT13 = &CpuTimer1_int13_isr; // CPU1 32bit Timer INT13

EDIS; // This is needed to disable write to EALLOW protected registers

EALLOW;

XIntruptRegs.XNMICTR = 0; //Counter (CPU_Timer1 = INT13)

EDIS;

MemCopy(&RamfuncsLoadStart, &RamfuncsLoadEnd, &RamfuncsRunStart);

InitFlash();

EPwm1TimerIntCount = 0;

IER |= M_INT3 | M_INT13; //CPU Interrupt 13 (CPUTimer1) and 3(ePWM1): Need to set IFR and IER

PieCtrlRegs.PIEIER3.bit.INTx1 = 1; // ePWM1_INT_ENABLE (ePWM1);

EINT; // Enable Global interrupt INTM

ERTM; // Enable Global realtime interrupt DBGM

interrupt void CpuTimer1_int13_isr(void) // CPU1 32bit Timer INT13

{

//======= Nested - Allow ePWM1 INT=============

int16 TempPIEIER;

if(State != 6) {

TempPIEIER = PieCtrlRegs. PIEIER3.all;

IER |= M_INT3; // Enable CPU INT3 which is connected to EPWM1-3 INT:

IER &= M_INT3;  //?????????????

PieCtrlRegs.PIEIER3.bit.INTx1 = 1; //Enable EPWM INT3 in the PIE:PWM1_INT_ENABLE INT3.1;

PieCtrlRegs.PIEACK.all = PIEACK_GROUP3; // Acknowledge this interrupt to receive more interrupts from group 3

asm(" NOP");

EINT; //asm(" CLRC INTM");

// COmmunication Code//

DINT;

PieCtrlRegs.PIEIER3.all = TempPIEIER;

EDIS;

}

3) Disable / Re - enable INT3.3 Code

void EEPROMB_Loop()

{

//Disable INT3.1

EALLOW;

IER = 0x1000;

PieCtrlRegs.PIEIER3.bit.INTx1 = 0;

PieCtrlRegs.PIEACK.all = 0;

EDIS;

Update_EEPROMB(); // EEPROMB Programming

if(Enables == 0x0C) // Reset / Close

{

// Enable INT3.1

State = 2; // initialize and Reload EEPROMB Parameteres

EALLOW;

PieCtrlRegs.PIEIER3.bit.INTx1 = 1;

//IER = 0x1004;

IER |= M_INT3; //0x1004;

PieCtrlRegs.PIEIER3.bit.INTx1 = 1;

PieCtrlRegs.PIEACK.all = 0;

EDIS;

}

This code halts INT3.3 and continues INT13, but I lose INT13_ISR when I re-enable INT3.3 (IER=0x0000/4). I am not sure why, useless the nesting code is causing an issue?? Also I am not sure why the IER &= M_INT3 is used in the nesting algorithm (http://processors.wiki.ti.com/index.php/Interrupt_Nesting_on_C28x   ) .

Thank you for any help

John