TMS320F28335: CMPA value not changing according to ADC input.Close loop PI control

Hello,

Did you use any reference C2000Ware example? Can you please try stepping through each line of your code to see if configurations/variable values change as expected? And you can check that your ISRs are occurring properly. This will help to narrow down the source of when things diverge from what you are expecting to occur.

Best Regards,

Allison

Hi,

I will be able to check whether the values of registers by next week and will let you know ,till then kindly confirm does the verion of CCS also impact the result? i am using ccs7.4

Thanks

Ayush

Hi Ayush,

Yes, please let me know any findings. And the CCS version should not have any affect on the result - so no need to worry about that (though, is there a reason you haven't tried a newer CCS version?).

Though this does not directly apply to your case, I also wanted to add that for newer generation devices (with DriverLib and SysConfig implementation), we have a walk-through example on the C2000 Academy that uses ADC conversion results to influence the output of a PWM. The instructions can be found HERE, and the lab exercise example projects can be found at {C2000Ware}\training\device\{device}\system_design\lab_systemdesign. Just wanted to be sure you know of it in case you use newer generation devices in the future or are simply curious!

Best Regards,

Allison

Hi , Allison

Sorry for late reply,i didnt had access to Laptop hence the dalay.

I have monitored the real time value of ADCRESULT0, ADCINT ,they are not changing even after varying the input values to ADC.Hence no change in duty

cycle of output.

PFA screen shot . and tell next course of action.

Regards

Ayush

Hi Ayush,

Could you put a while loop in your code and software trigger the ADC by writing AdcRegs.ADCTRL2.bit.SOC_SEQ1 to 1?

This way we can make sure that your ADC SEQ1 and interrupt is set up correctly. Have you used any of our ADC examples for F2833X devices?  

Best Regards,

Ben Collier

Hi Ben

I have added the while loop in code.Kindly verify from your end

Thanks and Regards

Ayush

 .

#include "DSP28x_Project.h"     // Device Headerfile and Examples Include File
#include "DCL.h"
#include "DCLF32.h"
#include "DCL_fdlog.h"
#include "DCLC28.h"

// Function Prototypes
__interrupt void adc_isr(void);

DCL_PI pi1 = PI_DEFAULTS;

// Globals
Uint16 LoopCount;
Uint16 ConversionCount;
float Voltage1;
float U = 0.5f;
float rk = 0.6f;
float yk;
float uk = 0.5f;

void InitEPwm1(void);
void gpio_select(void);

//
// Main
//
void main(void)
{
    // Step 1. Initialize System Control: PLL, WatchDog, enable Peripheral Clocks
    InitSysCtrl();

    EALLOW;
    #if (CPU_FRQ_150MHZ)     // Default - 150 MHz SYSCLKOUT
        #define ADC_MODCLK 0x3
    #endif
    #if (CPU_FRQ_100MHZ)
        #define ADC_MODCLK 0x2
    #endif
    EDIS;

    // Define ADCCLK clock frequency ( less than or equal to 25 MHz )
    EALLOW;
    SysCtrlRegs.HISPCP.all = ADC_MODCLK;
    EDIS;

    // Step 2. Initialize GPIO:
    // InitGpio();  // Skipped for this example

    // Step 3. Clear all interrupts and initialize PIE vector table:
    DINT;

    InitPieCtrl();

    IER = 0x0000;
    IFR = 0x0000;

    InitPieVectTable();

    EALLOW;  // This is needed to write to EALLOW protected register
    PieVectTable.ADCINT = &adc_isr;
    EDIS;    // This is needed to disable write to EALLOW protected registers

    // Step 4. Initialize all the Device Peripherals:
    InitAdc();  // For this example, init the ADC

    // Step 5. User specific code, enable interrupts:
    PieCtrlRegs.PIEIER1.bit.INTx6 = 1;
    IER |= M_INT1;      // Enable CPU Interrupt 1
    EINT;               // Enable Global interrupt INTM
    ERTM;               // Enable Global realtime interrupt DBGM

    LoopCount = 0;
    ConversionCount = 0;

    // Configure ADC
    AdcRegs.ADCMAXCONV.all = 0x0001;       // Setup 2 conv's on SEQ1
    AdcRegs.ADCCHSELSEQ1.bit.CONV00 = 0x3; // Setup ADCINA3 as 1st SEQ1 conv.
    AdcRegs.ADCCHSELSEQ1.bit.CONV01 = 0x2; // Setup ADCINA2 as 2nd SEQ1 conv.

    AdcRegs.ADCTRL2.bit.INT_ENA_SEQ1 = 1;  // Enable SEQ1 interrupt (every EOS)

    // Configure ePWM1
    InitEPwm1();

    // Configure GPIO
    gpio_select();

    // Main loop
    while (1)
    {
        // Start ADC conversion sequence 1
        AdcRegs.ADCTRL2.bit.SOC_SEQ1 = 1;

        // Wait for ADC conversion to complete
        while (AdcRegs.ADCST.bit.INT_SEQ1 == 0);

        // Read ADC result from result register (e.g., from the first channel)
        yk = ((int)AdcRegs.ADCRESULT0 >> 4) * 300.0f / 4095.0f;

        // Process the ADC result
        uk = DCL_runPI_C2(&pi1, rk, yk);
        if (uk > 0.8f) {
            uk = 0.8f;
        } else if (uk < 0.1f) {
            uk = 0.1f;
        }

        EPwm1Regs.CMPA.half.CMPA = (EPwm1Regs.TBPRD) * uk;  // Set compare A value
        EPwm1Regs.CMPB = EPwm1Regs.TBPRD * uk;              // Set Compare B value

        // Clear the interrupt flag and reset sequencer
        AdcRegs.ADCST.bit.INT_SEQ1_CLR = 1;
        AdcRegs.ADCTRL2.bit.RST_SEQ1 = 1;

        LoopCount++;
    }
}

void InitEPwm1(void)
{
    EPwm1Regs.TBCTL.bit.CTRMODE = 0; // Count up down
    EPwm1Regs.TBPRD = 37500;       // Set timer period
    EPwm1Regs.TBCTL.bit.PHSEN = TB_DISABLE;    // Disable phase loading
    EPwm1Regs.TBPHS.half.TBPHS = 0x0000;       // Phase is 0
    EPwm1Regs.TBCTR = 0x0000;                  // Clear counter
    EPwm1Regs.TBCTL.bit.HSPCLKDIV = 0x001;   // Clock ratio to SYSCLKOUT
    EPwm1Regs.TBCTL.bit.CLKDIV = 000;
    EPwm1Regs.TBCTL.bit.SYNCOSEL = 1;
    EPwm1Regs.CMPA.half.CMPA = 10000;    // Set compare A value
    EPwm1Regs.CMPB = 10000;              // Set Compare B value
    EPwm1Regs.DBCTL.bit.OUT_MODE = 3;
    EPwm1Regs.DBCTL.bit.POLSEL = 2;
    EPwm1Regs.DBCTL.bit.IN_MODE = 0;
    EPwm1Regs.DBRED = 100;
    EPwm1Regs.DBFED = 100;
    EPwm1Regs.ETSEL.bit.SOCAEN = 1;     // Enable SOC on A group
    EPwm1Regs.ETSEL.bit.SOCASEL = 4;    // Select SOC from CPMA on upcount
    EPwm1Regs.ETPS.bit.SOCAPRD = 1;     // Generate pulse on 1st event

    EPwm1Regs.AQCTLA.bit.ZRO = 2;    // Set PWM1A on Zero
    EPwm1Regs.AQCTLA.bit.CAU = 1;
}

void gpio_select(void)
{
    EALLOW;
    GpioCtrlRegs.GPAPUD.bit.GPIO0 = 0;   // Enable pullup on GPIO0
    GpioCtrlRegs.GPAPUD.bit.GPIO1 = 0;   // Enable pullup on GPIO1
    GpioCtrlRegs.GPAMUX1.bit.GPIO0 = 1;  // GPIO0 = PWM1A
    GpioCtrlRegs.GPAMUX1.bit.GPIO1 = 1;  // GPIO1 = PWM1B
    EDIS;
}

__interrupt void adc_isr(void)
{
    yk = ((int)AdcRegs.ADCRESULT0 >> 4) * 300.0f / 4095.0f;

    uk = DCL_runPI_C2(&pi1, rk, yk);
    if (uk > 0.8f) {
        uk = 0.8f;
    } else if (uk < 0.1f) {
        uk = 0.1f;
    }

    EPwm1Regs.CMPA.half.CMPA = (EPwm1Regs.TBPRD) * uk;  // Set compare A value
    EPwm1Regs.CMPB = EPwm1Regs.TBPRD * uk;              // Set Compare B value

    if (ConversionCount == 9) {
        ConversionCount = 0;
    } else {
        ConversionCount++;
    }

    AdcRegs.ADCTRL2.bit.RST_SEQ1 = 1;         // Reset SEQ1
    AdcRegs.ADCST.bit.INT_SEQ1_CLR = 1;       // Clear INT SEQ1 bit
    PieCtrlRegs.PIEACK.all = PIEACK_GROUP1;   // Acknowledge interrupt to PIE

    return;
}

Hi Ayush,

In your current while(1) loop, the SOC will only be triggered once if the interrupt is not set up correctly. Could you change your while(1) loop so that it only contains the software SOC trigger?

Also, have you used any of our ADC examples for F2833X devices?

Best Regards,

Ben Collier

In this code i have changed rk from constant to 100 to 0 slope function by adding while loop.

kindly verify if coding is correct or not.

Thanks

while (1)
{
// Update the time counter
timeCounter++;

// Determine the reference signal value
if (timeCounter < constantDuration)
{
// Constant phase
rk = 100.0f;
}
else
{
// Ramp down phase
rk = 100.0f + rampRate * (timeCounter - constantDuration);
if (rk < 0.0f)
{
rk = 0.0f; // Clamp to 0 to prevent going below 0
}
}

// Start ADC conversion sequence 1
AdcRegs.ADCTRL2.bit.SOC_SEQ1 = 1;

// Wait for ADC conversion to complete
while (AdcRegs.ADCST.bit.INT_SEQ1 == 0);

// Read ADC result from result register (e.g., from the first channel)
yk = ((int)AdcRegs.ADCRESULT0 >> 4) * 300.0f / 4095.0f;

// Process the ADC result
uk = DCL_runPI_C2(&pi1, rk, yk);
if (uk > 0.8f) {
uk = 0.8f;
} else if (uk < 0.1f) {
uk = 0.1f;
}

// Set PWM duty cycle based on the control output
EPwm1Regs.CMPA.half.CMPA = (EPwm1Regs.TBPRD) * uk;
EPwm1Regs.CMPB = EPwm1Regs.TBPRD * uk;
}

Ayush,

I cannot comment on the functionality of your control code. I just want to make sure that your ADC is triggering as expected.

Could you include only the following line in your while(1) loop? 

AdcRegs.ADCTRL2.bit.SOC_SEQ1 = 1;

Then could you check the ADC result register to make sure that you see the expected result? 

Thanks,

Ben Collier