TMS320F28069: Measure ADC value

i got this error for everytime.

Hello Bhashini,

Have you verified that the VREFHI and VREFLO are correct for the ADC? Are you using internal or external reference? Are you using interrupts, and if so have you verified there is sufficient sample/hold time for sampling the ADC?

Best regards,

Omer Amir

//###########################################################################
//
// FILE:   Example_2806xAdcSoc.c
//
// TITLE:  ADC Start of Conversion Example
//
//! \addtogroup f2806x_example_list
//! <h1> ADC Start of Conversion (adc_soc)</h1>
//! 
//! This ADC example uses ePWM1 to generate a periodic ADC SOC - ADCINT1.
//! Two channels are converted, ADCINA4 and ADCINA2.
//! 
//! \b Watch \b Variables \n
//! - Voltage1[10]    - Last 10 ADCRESULT0 values
//! - Voltage2[10]    - Last 10 ADCRESULT1 values
//! - ConversionCount - Current result number 0-9
//! - LoopCount       - Idle loop counter
//
//###########################################################################
// $TI Release: $
// $Release Date: $
// $Copyright:
// Copyright (C) 2009-2023 Texas Instruments Incorporated - http://www.ti.com/
//
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// modification, are permitted provided that the following conditions 
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// 
//   Redistributions of source code must retain the above copyright 
//   notice, this list of conditions and the following disclaimer.
// 
//   Redistributions in binary form must reproduce the above copyright
//   notice, this list of conditions and the following disclaimer in the 
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// 
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// 
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// $
//###########################################################################

//
// Included Files
//
#include "DSP28x_Project.h"     // Device Headerfile and Examples Include File

//
// Function Prototypes
//
__interrupt void adc_isr(void);
void Adc_Config(void);

//
// Globals
//
Uint16 LoopCount;
Uint16 ConversionCount;
Uint16 Voltage1[10];
Uint16 Voltage2[10];

//
// Main
// 
void main(void)
{
    //
    // Step 1. Initialize System Control:
    // PLL, WatchDog, enable Peripheral Clocks
    // This example function is found in the F2806x_SysCtrl.c file.
    //
    InitSysCtrl();

    //
    // Step 2. Initialize GPIO:
    // This example function is found in the F2806x_Gpio.c file and
    // illustrates how to set the GPIO to it's default state.
    //
    // InitGpio();  // Skipped for this example

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

    //
    // Initialize the PIE control registers to their default state.
    // The default state is all PIE interrupts disabled and flags
    // are cleared.
    // This function is found in the F2806x_PieCtrl.c file.
    //
    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).
    // 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 F2806x_DefaultIsr.c.
    // This function is found in F2806x_PieVect.c.
    //
    InitPieVectTable();

    //
    // Interrupts that are used in this example are re-mapped to
    // ISR functions found within this file.
    //
    EALLOW;  // This is needed to write to EALLOW protected register
    PieVectTable.ADCINT1 = &adc_isr; //interrupt service request
    EDIS;    // This is needed to disable write to EALLOW protected registers

    //
    // Step 4. Initialize all the Device Peripherals:
    // This function is found in F2806x_InitPeripherals.c
    // InitPeripherals(); // Not required for this example
    //
    InitAdc();  // For this example, init the ADC
    AdcOffsetSelfCal();//ADC Zero Offset Calibration

    //
    // Step 5. User specific code, enable interrupts:
    //

    //
    // Enable ADCINT1 in PIE
    //
    PieCtrlRegs.PIEIER1.bit.INTx1 = 1; // Enable INT 1.1 in the PIE
    IER |= M_INT1; 					   // Enable CPU Interrupt 1
    EINT;          					   // Enable Global interrupt INTM
    ERTM;          					   // Enable Global realtime interrupt DBGM

    LoopCount = 0;
    ConversionCount = 0;

    //
    // Configure ADC
    //
    EALLOW;
    AdcRegs.ADCCTL2.bit.ADCNONOVERLAP = 1; // Enable non-overlap mode - overlap sample is not allowed
    
    //
    // ADCINT1 trips after AdcResults latch
    //
    AdcRegs.ADCCTL1.bit.INTPULSEPOS	= 1; // INt Pulse generation occurs 1 cycle prior to ADC result latching into its result register
    
    AdcRegs.INTSEL1N2.bit.INT1E     = 1;  // Enabled ADCINT1
    AdcRegs.INTSEL1N2.bit.INT1CONT  = 0;  // Disable ADCINT1 Continuous mode
    
    //
    // setup EOC1 to trigger ADCINT1 to fire
    //
    AdcRegs.INTSEL1N2.bit.INT1SEL 	= 1;
    
    AdcRegs.ADCSOC0CTL.bit.CHSEL 	= 4;  // set SOC0 channel select to ADCINA4
    AdcRegs.ADCSOC1CTL.bit.CHSEL 	= 2;  // set SOC1 channel select to ADCINA2
    
    //
    // set SOC0 start trigger on EPWM1A, due to round-robin SOC0 converts
    // first then SOC1
    //
    AdcRegs.ADCSOC0CTL.bit.TRIGSEL 	= 5;
    
    //
    // set SOC1 start trigger on EPWM1A, due to round-robin SOC0 converts 
    // first then SOC1
    //
    AdcRegs.ADCSOC1CTL.bit.TRIGSEL 	= 5;
    
    //
    // set SOC0 S/H Window to 7 ADC Clock Cycles, (6 ACQPS plus 1)
    //
    AdcRegs.ADCSOC0CTL.bit.ACQPS 	= 6;
    
    //
    // set SOC1 S/H Window to 7 ADC Clock Cycles, (6 ACQPS plus 1)
    //    
    AdcRegs.ADCSOC1CTL.bit.ACQPS 	= 6;
    EDIS;

    //
    // 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 CMPA 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
    //
    for(;;)
    {
        LoopCount++;
    }
}

//
// adc_isr - 
//
__interrupt void
adc_isr(void)
{
    Voltage1[ConversionCount] = AdcResult.ADCRESULT0;
    Voltage2[ConversionCount] = AdcResult.ADCRESULT1;
    
    //
    // If 20 conversions have been logged, start over
    //
    if(ConversionCount == 9)
    {
        ConversionCount = 0;
    }
    else
    {
        ConversionCount++;
    }

    //
    // Clear ADCINT1 flag reinitialize for next SOC
    //
    AdcRegs.ADCINTFLGCLR.bit.ADCINT1 = 1;
    
    PieCtrlRegs.PIEACK.all = PIEACK_GROUP1;   // Acknowledge interrupt to PIE

    return;
}

//
// End of File
//

1.Hi. Above is the code i used to test. I used TMS320F28069 development board and supply 3.3V and 0V to  ADCINA4 and ADCINA2 pins. i used 3.3V pin in the development board to supply 3.3V and ground to supply 0V. i connected these pins using jumper wires. then build and debug the above example and use live expressions to see the values of Voltage1 and Voltage2. but as per the calculations the expected values for 0V is 0 and 3.3V is 4095. but i didnt observe those values in the live expression. i need to solve this error first.

2. Then i need to change the above code so that it displays the output of ADCINB1 which is 29th pin in the above mentioned MCU. 

Hello Omer, thank you for your support. when i change the ACQPS to 25 it works as i expected. Thank you very much.