f28035 epwm interrupt on ZERO or CMP?

Dave,

Unfortunately you can't do both together.  The INTSEL field in the ETSEL register for ePWM2 will allow you to select one trigger source or the other, but not both.

What you can to is change the INTSEL bits from within the ISR, so the zero match ISR writes 100 (assuming it's up-counting), and the compare match ISR writes 001.  You can check the I/O pin in the ISR by reading the GPADAT register to determine which event triggered the interrupt.

Regards,

Richard

Hi Richard,

Thank you for the response. When you say the ISR writes xxx, what register are you referring to?

Thank you,
Dave

Richard,

I believe I understand now. You are discussing writing the compare mode. Not reading a status register. I will work on implementation.

Thank you.

Hi Brett,

Please see my code snippet below. PWM2 is running at 15 Hz. PWM1 (Piezo_PWM ) is 6.25 KHz (no interrupt). When running I only see epwm2_isr_cnt and epwm_low_cnt incrementing. However if I place a breakpoint on the "epqm2_GPIO_state = " assignment line and step through, epqm2_GPIO_state is always 1 as expected. Why does this not work at run time? I also tried loading into FLASH with same results. I am running a Piccolo F28035 control card in docking board.

//////////////////// PWM2 interrupt code
Uint32 epwm_high_cnt = 0;
Uint32 epwm_low_cnt = 0;
Uint32 epwm2_isr_cnt = 0;
volatile Uint16 epqm2_GPIO_state;
__interrupt void epwm2_isr(void)
{
// Update the CMPA and CMPB values
epwm2_isr_cnt++;
epqm2_GPIO_state = GpioDataRegs.GPADAT.bit.GPIO2; // Get ePWM output pin state
epqm2_GPIO_state = GpioDataRegs.GPADAT.bit.GPIO2; // Get ePWM output pin state
if(epqm2_GPIO_state == 1)
{
epwm_high_cnt++;
Piezo_PWM = EPWM1_TIMER_TBPRD / 2; // Set DAC PWM to full on
// EPwm2Regs.ETSEL.bit.INTSEL = ET_CTRD_CMPA; // Select INT on Zero event
}
else
{
epwm_low_cnt++;
Piezo_PWM = 0; // Set DAC PWM to full on
// EPwm2Regs.ETSEL.bit.INTSEL = ET_CTR_ZERO; // Select INT on Zero event
}
// Clear INT flag for this timer
EPwm2Regs.ETCLR.bit.INT = 1;
EPwm1Regs.ETSEL.bit.INTEN = 1; // Enable INT
// Acknowledge this interrupt to receive more interrupts from group 3
PieCtrlRegs.PIEACK.all = PIEACK_GROUP3;
}


///////////////////// PWM2 init code
void InitEPwm2Example()
{
// Setup TBCLK
EPwm2Regs.TBCTL.bit.CTRMODE = TB_COUNT_UP; // Count up
EPwm2Regs.TBPRD = EPWM2_TIMER_TBPRD; // Set timer period
EPwm2Regs.TBCTL.bit.PHSEN = TB_DISABLE; // Disable phase loading
EPwm2Regs.TBPHS.half.TBPHS = 0x0000; // Phase is 0
EPwm2Regs.TBCTR = 0x0000; // Clear counter
EPwm2Regs.TBCTL.bit.HSPCLKDIV = TB_DIV32; // Clock ratio to SYSCLKOUT
EPwm2Regs.TBCTL.bit.CLKDIV = TB_DIV32;

// Setup shadow register load on ZERO
EPwm2Regs.CMPCTL.bit.SHDWAMODE = CC_SHADOW;
EPwm2Regs.CMPCTL.bit.SHDWBMODE = CC_SHADOW;
EPwm2Regs.CMPCTL.bit.LOADAMODE = CC_CTR_ZERO;
EPwm2Regs.CMPCTL.bit.LOADBMODE = CC_CTR_ZERO;

// Set Compare values
EPwm2Regs.CMPA.half.CMPA = EPWM2_MIN_CMPA; // Set compare A value
EPwm2Regs.CMPB = EPWM2_MAX_CMPB; // Set Compare B value

// Set actions
EPwm2Regs.AQCTLA.bit.ZRO = AQ_SET; // Clear PWM2A on Period
EPwm2Regs.AQCTLA.bit.CAU = AQ_CLEAR; // Set PWM2A on event A, up count

EPwm2Regs.AQCTLB.bit.ZRO = AQ_SET; // Clear PWM2B on Period
EPwm2Regs.AQCTLB.bit.CBU = AQ_CLEAR; // Set PWM2B on event B, up count

// Interrupt where we will change the Compare Values
// EPwm2Regs.ETSEL.bit.INTSEL = (ET_CTR_ZERO | ET_CTRU_CMPA); // Select INT on Zero event
EPwm2Regs.ETSEL.bit.INTSEL = ET_CTR_ZERO; // Select INT on Zero event
EPwm2Regs.ETSEL.bit.INTEN = 1; // Enable INT
EPwm2Regs.ETPS.bit.INTPRD = ET_1ST; // Generate INT on every event

// Information this example uses to keep track
// of the direction the CMPA/CMPB values are
// moving, the min and max allowed values and
// a pointer to the correct ePWM registers
epwm2_info.EPwm_CMPA_Direction = EPWM_CMP_UP; // Start by increasing CMPA
epwm2_info.EPwm_CMPB_Direction = EPWM_CMP_UP; // and decreasing CMPB
epwm2_info.EPwmTimerIntCount = 0; // Zero the interrupt counter
epwm2_info.EPwmRegHandle = &EPwm2Regs; // Set the pointer to the ePWM module
epwm2_info.EPwmMaxCMPA = EPWM2_MAX_CMPA; // Setup min/max CMPA/CMPB values
epwm2_info.EPwmMinCMPA = EPWM2_MIN_CMPA;
epwm2_info.EPwmMaxCMPB = EPWM2_MAX_CMPB;
epwm2_info.EPwmMinCMPB = EPWM2_MIN_CMPB;
}

Pleas advise.

Thanks,
Dave