Hi,
I am using T1 in the Action Qualifier Submodule to clear EPWM1A Lo, but it looks like the output is instead going high impedance. Perhaps there is some configuration I am overlooking?
Background/Setup:
I originally was trying to verify ADC conversion time. The signal measured by the ADC is the output of DACA, which is initially set to a low value. Using the PPB, if the measurement is too high, TRIPHI causes an event which is identified by the Digital Comparator. This causes a T1 event which is configured to drive the EPWM1A Lo.
EPWM1A is configured to 5us period at 80% duty. Time Base is up count. EPWM1A is Set Hi on TBCTR = 0, and Cleared Lo on CMPA.
To do the test, initially DACA is below the PPB TRIPHI threshold and EPWM1A is running. Using the watch window, DACA is set above the trip level. SOC0 is started on the next rising PWM edge. Once the conversion is complete, EPWM1A Lo will be terminated.
Results:
I have attached an image of the waveform. Yellow is the PWM and Pink is the DACA.
If I use the Action Qualifier Submodule T1, I get the "high impedance" looking result.
If I use CBC Trip Zone, the test works.
Code:
void main(void)
{
//////////////////////////////////
///// Generic Initialization /////
//////////////////////////////////
// Initialize device clock and peripherals
InitSysCtrl();
// Initialize GPIO and configure the GPIO pin as a push-pull output
InitGpio();
GPIO_SetupPinMux(DEVICE_GPIO_PIN_LED1, GPIO_MUX_CPU1, 0);
GPIO_SetupPinOptions(DEVICE_GPIO_PIN_LED1, GPIO_OUTPUT, GPIO_PUSHPULL);
GPIO_SetupPinMux(DEVICE_GPIO_PIN_LED2, GPIO_MUX_CPU1, 0);
GPIO_SetupPinOptions(DEVICE_GPIO_PIN_LED2, GPIO_OUTPUT, GPIO_PUSHPULL);
GpioDataRegs.GPASET.bit.GPIO31 = 1; // left LED
GpioDataRegs.GPBSET.bit.GPIO34 = 1; // Right LED
//////////////////////////////////
///// Generic Interrupt Init /////
//////////////////////////////////
// Initialize PIE and clear PIE registers. Disables CPU interrupts.
DINT;
InitPieCtrl();
// Disable CPU interrupts and clear all CPU interrupt flags
IER = 0x0000;
IFR = 0x0000;
// Initialize the PIE vector table with pointers to the shell Interrupt
// Service Routines (ISR).
InitPieVectTable();
// Enable Global Interrupt (INTM) and realtime interrupt (DBGM)
EnableInterrupts();
EINT;
ERTM;
//CMPSS_investigation();
ADC_investigation();
// Loop Forever
for(;;)
{
DacaRegs.DACVALS.all = iSNS; // update in watch window as needed
ADC_test();
}
}
void ADC_investigation(void)
{
/* Plan
* - EPWM1A is configured for 5us period. Configure 80% duty. HI on ZRO, LOW on CMPA = 4000.
* - DACA is turned on for measurement by A0 (SOC0)
* - SOC0 starts with EPWM1A zero. To facilitate testing, SOC0 will be dis/enabled in the debug window as needed
* 1. PPB to check limit hi, limit lo, verify measurement result [DONE]
* 2. Use PPB to terminate EPWM1A. Should provide conversion timing measurement.
*/
///////////////////////////////////////////////
///// Initial Setup ///////
///////////////////////////////////////////////
///// EPWM1A ///////
GPIO_SetupPinMux(DEVICE_GPIO_PIN_EPWM1A, GPIO_MUX_CPU1, 1);
EALLOW;
//CpuSysRegs.PCLKCR0.bit.TBCLKSYNC = 0;
EPwm1Regs.TBCTL.bit.HSPCLKDIV = 0; // 0 = SYSCLK/1, 1 = SYSCLK/2 (default)
EPwm1Regs.TBCTL.bit.FREE_SOFT = 2; // run during debug mode halts
EPwm1Regs.TBCTL.bit.CTRMODE = TB_COUNT_UP; // count up (arbitrary for this)
EPwm1Regs.TBPRD = 500; // Period = 500 counts @ 100MHz = 5us
EPwm1Regs.CMPA.bit.CMPA = 400; // Will use CMPA to set PWM LO @ 80% Duty Fixed
EPwm1Regs.AQCTLA.bit.ZRO = 2; // Set HI every period
EPwm1Regs.AQCTLA.bit.CAU = 1; // Set LO every CMPA
EPwm1Regs.ETSEL.bit.SOCASEL = 1; // 1 = SOCA on ZRO
EPwm1Regs.ETPS.bit.SOCAPRD = 1; // 1 = generate SOCA on first event
EPwm1Regs.ETSEL.bit.SOCAEN = 1; // 1 = Enable SOCA Trigger on ZRO
EDIS;
///// DACA ///////
EALLOW;
AnalogSubsysRegs.ANAREFCTL.bit.ANAREFASEL = 0; // 0 = internal, 1 = external (default)
AnalogSubsysRegs.ANAREFCTL.bit.ANAREFA2P5SEL = 0; // 0 = 1.65V (default), 1 = 2.5V
DacaRegs.DACCTL.bit.LOADMODE = 0; // 0 = update DAC on sysclk (default), 1 = EPWMSYNCO
DacaRegs.DACCTL.bit.DACREFSEL = 1; // 0 = Reference: VDAC (external, default), 1 = ADC reference (set above)
DacaRegs.DACCTL.bit.MODE = 1; // 0 = Gain x1 (default), 1 = Gain x2
DacaRegs.DACOUTEN.bit.DACOUTEN = 1;
DELAY_US(5000); // max power up time per datasheet is 5000us
DacaRegs.DACVALS.all = iSNS; // halfway point of 2^12 (1.65/2 = 0.825V, 2.5/2 = 1.25V)
EDIS;
///// ADC ///////
EALLOW;
// Use ADC to measure DAC (DACA and A0 are same pin, so use A0)
// Internal Vref already setup setup; VrefA is shared between ADCA and DACA
// AnalogSubsysRegs.ANAREFCTL.bit.ANAREFASEL = 0; // 0 = internal, 1 = external (default)
// AnalogSubsysRegs.ANAREFCTL.bit.ANAREFA2P5SEL = 0; // 0 = 1.65V (default), 1 = 2.5V
// Setup A0 as SOC0
AdcaRegs.ADCSOC0CTL.bit.CHSEL = 0; // SOC0 will convert A0 (DACA_OUT)
AdcaRegs.ADCSOC0CTL.bit.ACQPS = 9; // 9+1=10, Minimum window is 75 ns SYSCLK cycles (arbitrary at this point)
AdcaRegs.ADCSOC0CTL.bit.TRIGSEL = 5; // Trigger by ePWM1, ADCSOCA
AdcaRegs.ADCCTL2.bit.PRESCALE = 2; // 2 = divide SYSCLK by 2; need to prescale 100MHZ SYSCLK to 50MHZ max.
AdcaRegs.ADCCTL1.bit.ADCPWDNZ = 1; // turn on ADCA module
EDIS;
DELAY_US(1000); // delay allowing for ADC power up time
///////////////////////////////////////////////
///// 1. PPB to check limit hi, limit lo /////
///////////////////////////////////////////////
EALLOW;
AdcaRegs.ADCPPB4CONFIG.bit.CBCEN = 1; // 1 = Enable CBC, 0 = disabled (default)
AdcaRegs.ADCPPB4CONFIG.bit.CONFIG = 0; // 0 (default) = PPB1 is linked to SOC0
AdcaRegs.ADCPPB4TRIPHI.bit.LIMITHI = limit_HI;
AdcaRegs.ADCPPB4TRIPLO.bit.LIMITLO = limit_LO;
AdcaRegs.ADCEVTSEL.bit.PPB4TRIPHI = 1; // Enable PPB1 Trip HI to PWM
AdcaRegs.ADCEVTSEL.bit.PPB4TRIPLO = 1; // Enable PPB1 TRIP LO to PWM
AdcaRegs.ADCPPB4OFFCAL.all = 0x200; // 0x200 = +512
//AdcaRegs.ADCPPB4OFFREF = 500; // subtract 500
AdcaRegs.ADCEVTCLR.all = 0xFFFF; // Clear any pending flags
EDIS;
///////////////////////////////////////////////
////// 2. Use PPB to terminate EPWM1A ///////
///////////////////////////////////////////////
/* Setup ePWM XBAR and Digital Comparator.
* Input to XBAR comes from ADCA EVENT4, output is TRIP4 which is fed to Digital Comparator.
* DCAEVT2 is used to terminate EPWM1A. */
EALLOW;
EPwmXbarRegs.TRIP4MUX0TO15CFG.bit.MUX6 = 2; // Select input 6 of XBAR TRIP MUX to be ADCAEVT4 (PPB4)
EPwmXbarRegs.TRIP4MUXENABLE.bit.MUX6 = 1; // Enable input 6 to trigger Trip 4
EPwm1Regs.DCTRIPSEL.bit.DCAHCOMPSEL = 3; // TRIPIN4 on digital comparator +in
EPwm1Regs.DCTRIPSEL.bit.DCALCOMPSEL = 3; // TRIPIN4 on digital comparator -in (not needed)
EPwm1Regs.TZDCSEL.bit.DCAEVT2 = 2; // digital comparator DCAEVT2 high on DCAH assertion (TRIP4 high).
// These new registers are active by default, disable them.
EPwm1Regs.TZCTLDCA.all = 0xFFFF;
EPwm1Regs.TZCTLDCB.all = 0xFFFF;
// force low on AQ T1, this code doesn't work
EPwm1Regs.AQTSRCSEL.bit.T1SEL = 1; // 1 = T1 trips on DCAEVT2
EPwm1Regs.AQCTLA2.bit.T1U = 1; // 1 = force LO on T1
// force low on Trip Zone, this code works
//EPwm1Regs.TZCTL.bit.DCAEVT2 = 2;
EDIS;
}
void ADC_test(void)
{
if (AdcaRegs.ADCEVTSTAT.bit.PPB4TRIPHI == 1)
{
GpioDataRegs.GPACLEAR.bit.GPIO31 = 1; // left LED
GpioDataRegs.GPBSET.bit.GPIO34 = 1; // Right LED
//AdcaRegs.ADCEVTCLR.bit.PPB4TRIPHI = 1;
}
else if (AdcaRegs.ADCEVTSTAT.bit.PPB4TRIPLO == 1)
{
GpioDataRegs.GPASET.bit.GPIO31 = 1; // Left LED
GpioDataRegs.GPBCLEAR.bit.GPIO34 = 1; // Right LED
//AdcaRegs.ADCEVTCLR.bit.PPB4TRIPLO = 1;
}
else
{
GpioDataRegs.GPASET.bit.GPIO31 = 1; // left LED
GpioDataRegs.GPBSET.bit.GPIO34 = 1; // Right LED
}
}
