CCS/TMS320F28335: how to read ADC values simultaneously and as fast as possible?

Ata Khiabani

Part Number: TMS320F28335

Tool/software: Code Composer Studio

Hello

I am trying to do a project in which I need to read three values using ADC and do some processing on these data and select appropriate GPIO. Also I need to measure the elapsed time in each loop and use that time in my calculations. I have used three examples : ADCSOC, CpuTimer, GPIOSetup. My questions:

1. When I get ADC values, and watch them in variables they change to a value and then change to zero and continue to do this. How can I read the ADC values simultaneously and as fast as possible. (I don't know which triggering is the fastest). Which parts of the code should I change?

2. After building the project I get an error: "warning #10063-D: entry-point symbol other than "_c_int00" specified: "code_start"". What is this error?

I am copying my code here, I really appreciate it if you take a look and see which part of the code I need to change:



#include "DSP28x_Project.h"     // Device Headerfile and Examples Include File
#include <math.h>

// functions
void delay_loop(void);
void Gpio_select(void);
void Gpio_setup1(void);
void Gpio_setup2(void);
void Gpio_setup3(void);
void StartTimer(void);
void StopTimer(void);
void adc_isr(void);

double phi1(double cur, double vol, double t);

double phi2(double cur, double vol, double t);

double phi3(double cur, double vol, double t);

double phi4(double cur, double vol, double t);

double phi5(double cur, double vol, double t);

double phi6(double cur, double vol, double t);


double phi16(double cur, double vol, double t);


double phi17(double cur, double vol, double t) ;

double phi18(double cur, double vol, double t);

double phi31(double cur, double vol, double t);

double phi32(double cur, double vol, double t);

double phi33(double cur, double vol, double t);



double f1_1(double cur, double vol);

double f1_2(double cur, double vol);

double f2_1(double cur, double vol);

double f2_2(double cur, double vol);

double f3_1(double cur, double vol);

double f3_2(double cur, double vol);




//global variables
int fr=50;    //frequency in Hertz
int fr_unit_change=1;
long double t1=0;
long double delta_time;
double cpuTime1;
double cpuTime2;
double cpuTime;
double LoopCount;
double ConversionCount;
double Voltage1;
double Voltage2;
double Voltage3;
double current=0;
double voltage=0;
double vol1=0;
double cur1=0;
double dt=0.00002;
double sum1=0;
double sum2=0;
double sum3=0;
double W[12] = {  115.9200,
                 0.4708,
                 1.0362,
                14.8852,
               228.9501,
                84.3829,
                -1.7023,
                -0.9528,
                -3.9271,
                -1.6024,
               -89.6407,
              -470.1129};

int R1=10;     //inductor internal resistance
double L1=560e-6;  //inductor
double C1=100e-6;  //capacitor
double Vs=3.3;       // input DC voltage
int RL=10;      // Load

int f=1;   // Changing time unit   t=f*tau
int a=1;       // normalizing capacitor voltage   Vc=a*vol
int b=1;       // normalizing inductor current   Il=b*cur
double w=2*3.14;



void main(void)
{
    InitSysCtrl();




    EALLOW;
    #define ADC_MODCLK 0x3
    EDIS;


    EALLOW;
    SysCtrlRegs.HISPCP.all = ADC_MODCLK;
    EDIS;

    DINT;
    InitPieCtrl();

    Gpio_select();

    //
    // 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).
    // This will populate the entire table, even if the interrupt
    // is not used in this example.  This is useful for debug purposes.
    // The shell ISR routines are found in DSP2833x_DefaultIsr.c.
    // This function is found in DSP2833x_PieVect.c.
    //
    InitPieVectTable();

    InitCpuTimers();   // For this example, only initialize the Cpu Timers
for(;;){
    StartTimer();
    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

    InitAdc();  // For this example, init the ADC
    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 = 0x0002;       // Setup 2 conv's on SEQ1
      AdcRegs.ADCCHSELSEQ1.bit.CONV00 = 0x2; // Setup ADCINA2 as 1st SEQ1 conv.
      AdcRegs.ADCCHSELSEQ1.bit.CONV01 = 0x3; // Setup ADCINA3 as 2nd SEQ1 conv.
      AdcRegs.ADCCHSELSEQ1.bit.CONV02 = 0x4;
      //
      // Enable SOCA from ePWM to start SEQ1
      //
      AdcRegs.ADCTRL2.bit.EPWM_SOCA_SEQ1 = 1;

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

      //
      // Assumes ePWM1 clock is already enabled in InitSysCtrl();
      //
      EPwm1Regs.ETSEL.bit.SOCAEN = 1;     // Enable SOC on A group
      EPwm1Regs.ETSEL.bit.SOCASEL = 4;    // Select SOC from from CPMA on upcount
      EPwm1Regs.ETPS.bit.SOCAPRD = 1;     // Generate pulse on 1st event
      EPwm1Regs.CMPA.half.CMPA = 0x0080;  // Set compare A value
      EPwm1Regs.TBPRD = 0xFFFF;           // Set period for ePWM1
      EPwm1Regs.TBCTL.bit.CTRMODE = 0;    // count up and start

      //
      // Wait for ADC interrupt
      //

      vol1 = voltage*3/4095;
      cur1 = current*3/4095;

      sum1=W[0]*phi1(f1_1(cur1,vol1),f1_2(cur1,vol1),fmod(t1,1)+dt)+W[1]*phi2(f1_1(cur1,vol1),f1_2(cur1,vol1),fmod(t1,1)+dt)+W[2]*phi3(f1_1(cur1,vol1),f1_2(cur1,vol1),fmod(t1,1)+dt)+W[3]*phi4(f1_1(cur1,vol1),f1_2(cur1,vol1),fmod(t1,1)+dt)+W[4]*phi5(f1_1(cur1,vol1),f1_2(cur1,vol1),fmod(t1,1)+dt)+W[5]*phi6(f1_1(cur1,vol1),f1_2(cur1,vol1),fmod(t1,1)+dt)+W[6]*phi16(f1_1(cur1,vol1),f1_2(cur1,vol1),fmod(t1,1)+dt)+W[7]*phi17(f1_1(cur1,vol1),f1_2(cur1,vol1),fmod(t1,1)+dt)+W[8]*phi18(f1_1(cur1,vol1),f1_2(cur1,vol1),fmod(t1,1)+dt)+W[9]*phi31(f1_1(cur1,vol1),f1_2(cur1,vol1),fmod(t1,1)+dt)+W[10]*phi32(f1_1(cur1,vol1),f1_2(cur1,vol1),fmod(t1,1)+dt)+W[11]*phi33(f1_1(cur1,vol1),f1_2(cur1,vol1),fmod(t1,1)+dt);

      sum2=W[0]*phi1(f2_1(cur1,vol1),f2_2(cur1,vol1),fmod(t1,1)+dt)+W[1]*phi2(f2_1(cur1,vol1),f2_2(cur1,vol1),fmod(t1,1)+dt)+W[2]*phi3(f2_1(cur1,vol1),f2_2(cur1,vol1),fmod(t1,1)+dt)+W[3]*phi4(f2_1(cur1,vol1),f2_2(cur1,vol1),fmod(t1,1)+dt)+W[4]*phi5(f2_1(cur1,vol1),f2_2(cur1,vol1),fmod(t1,1)+dt)+W[5]*phi6(f2_1(cur1,vol1),f2_2(cur1,vol1),fmod(t1,1)+dt)+W[6]*phi16(f2_1(cur1,vol1),f2_2(cur1,vol1),fmod(t1,1)+dt)+W[7]*phi17(f2_1(cur1,vol1),f2_2(cur1,vol1),fmod(t1,1)+dt)+W[8]*phi18(f2_1(cur1,vol1),f2_2(cur1,vol1),fmod(t1,1)+dt)+W[9]*phi31(f2_1(cur1,vol1),f2_2(cur1,vol1),fmod(t1,1)+dt)+W[10]*phi32(f2_1(cur1,vol1),f2_2(cur1,vol1),fmod(t1,1)+dt)+W[11]*phi33(f2_1(cur1,vol1),f2_2(cur1,vol1),fmod(t1,1)+dt);

      sum3=W[0]*phi1(f3_1(cur1,vol1),f3_2(cur1,vol1),fmod(t1,1)+dt)+W[1]*phi2(f3_1(cur1,vol1),f3_2(cur1,vol1),fmod(t1,1)+dt)+W[2]*phi3(f3_1(cur1,vol1),f3_2(cur1,vol1),fmod(t1,1)+dt)+W[3]*phi4(f3_1(cur1,vol1),f3_2(cur1,vol1),fmod(t1,1)+dt)+W[4]*phi5(f3_1(cur1,vol1),f3_2(cur1,vol1),fmod(t1,1)+dt)+W[5]*phi6(f3_1(cur1,vol1),f3_2(cur1,vol1),fmod(t1,1)+dt)+W[6]*phi16(f3_1(cur1,vol1),f3_2(cur1,vol1),fmod(t1,1)+dt)+W[7]*phi17(f3_1(cur1,vol1),f3_2(cur1,vol1),fmod(t1,1)+dt)+W[8]*phi18(f3_1(cur1,vol1),f3_2(cur1,vol1),fmod(t1,1)+dt)+W[9]*phi31(f3_1(cur1,vol1),f3_2(cur1,vol1),fmod(t1,1)+dt)+W[10]*phi32(f3_1(cur1,vol1),f3_2(cur1,vol1),fmod(t1,1)+dt)+W[11]*phi33(f3_1(cur1,vol1),f3_2(cur1,vol1),fmod(t1,1)+dt);

      if ((sum1<=sum2) && (sum1<=sum3)) {
          Gpio_setup1();
      }
      else if ((sum2<=sum1) && (sum2<=sum3)) {
          Gpio_setup2();
      }
      else {
          Gpio_setup3();
      }

      StopTimer();
      delta_time=cpuTime*6.66e-9;
      t1=t1+delta_time;
}
}

/////////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////

void Gpio_select(void)
{
    EALLOW;
    //GpioCtrlRegs.GPAPUD.bit.GPIO6 = 0;   // Enable pullup on GPIO6

    GpioCtrlRegs.GPAMUX1.bit.GPIO6 = 0; // GPIO6 = GPIO6
    GpioCtrlRegs.GPADIR.bit.GPIO6 = 1;   // GPIO6 = output
    GpioCtrlRegs.GPAMUX1.bit.GPIO7 = 0;
    GpioCtrlRegs.GPADIR.bit.GPIO7 = 1;
    GpioCtrlRegs.GPAMUX1.bit.GPIO8 = 0;
    GpioCtrlRegs.GPADIR.bit.GPIO8 = 1;
    GpioCtrlRegs.GPAMUX1.bit.GPIO9 = 0;
    GpioCtrlRegs.GPADIR.bit.GPIO9 = 1;
    EDIS;
}

/////////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////


void StartTimer(void)
{
   // cpuTime1 = 0;

    EALLOW;
    CpuTimer2Regs.TCR.bit.TRB = 1;        // Reset CPU timer to period value
    CpuTimer2Regs.TCR.bit.TSS = 0;        // Start or reset CPU timer 2
    cpuTime1 = CpuTimer2Regs.TIM.all;     // Get value of CPU Timer 2 before code
    EDIS;
}

void StopTimer(void)
{

    EALLOW;
    cpuTime2 = CpuTimer2Regs.TIM.all;    // Get value of CPU Timer 2 after code
    cpuTime = cpuTime1 - cpuTime2;     // Calculate time using cpuTimer2
    CpuTimer2Regs.TCR.bit.TSS = 1;        // Start or reset CPU timer 2
    EDIS;
}

/////////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////
__interrupt void
adc_isr(void)
{
    Voltage1 = AdcRegs.ADCRESULT0 >>4;
    Voltage2 = AdcRegs.ADCRESULT1 >>4;
    Voltage3 = AdcRegs.ADCRESULT2 >>4;
    current = Voltage2- Voltage1;
    voltage = Voltage3- Voltage2;

    //
    // If 40 conversions have been logged, start over
    //

    //
    // Reinitialize for next ADC sequence
    //
    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;
}

/////////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////

over 8 years ago

0 tlee over 8 years ago

TI__Guru 62975 points

Ata,

It looks like you have the full module initialization calls inside of your main() loop. This is not recommended because the initialization sequence can intrusively disrupt the modules during operation. I suspect this is why your ADC results are resetting to 0.

The ADC ISR is generally the easiest way to access the results soon after they are ready.

The entry-point warning is showing because by default the compiler will begin code execution at "_c_int00" where the C-environment is initialized. For these example projects, the code execution entry-point is overridden to "code_start" in xxx_CodeStartBranch.asm. This is primarily so that the watchdog can be disabled before jumping to the "_c_int00" section.

-Tommy

0 Ata Khiabani over 8 years ago in reply to tlee

Intellectual 780 points

Thank you Tommy.
Could you please specify which initialization you mean? because in the template examples all the initialization are in the main () loop.

0 tlee over 8 years ago in reply to Ata Khiabani

TI__Guru 62975 points

Just about everything in the for(;;) loop except for the actual math.

Module / Lab 6 might be helpful for reference: processors.wiki.ti.com/.../C2000_Archived_Workshops

C2000™︎ microcontrollers

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CCS/TMS320F28335: how to read ADC values simultaneously and as fast as possible?