TMS320F28379D: AC signla ADC using adc_ex2_soc_epwm example

Thank you so much.

I have two more questions.

1. Waveform in CCS

When I did ADC,  I put the AC input 1Vpp.

But the waveform in the CCS is clear.

I was thinking this is because of the high frequency of the input signal.

But it isn't... this is because lower frequency also werid.

What did I missed?

 1kHz

100Hz

60Hz

2. I wanted to transfer the ADC value to real value.

So I made ADCreal 

But it does not work. The ADCreal is initialized and it does not save the ADC value

Can you check the code?

// FILE: adc_ex2_soc_epwm.c

//

// TITLE: ADC ePWM Triggering

//

//! \addtogroup driver_example_list

//! <h1>ADC ePWM Triggering</h1>

//!

//! This example sets up ePWM1 to periodically trigger a conversion on ADCA.

//!

//! \b External \b Connections \n

//! - A0 should be connected to a signal to convert

//!

//! \b Watch \b Variables \n

//! - \b adcAResults - A sequence of analog-to-digital conversion samples from

//! pin A0. The time between samples is determined based on the period

//! of the ePWM timer.

//!

//

//#############################################################################

// $TI Release: F2837xD Support Library v3.12.00.00 $

// $Release Date: Fri Feb 12 19:03:23 IST 2021 $

// $Copyright:

// Copyright (C) 2013-2021 Texas Instruments Incorporated - http://www.ti.com/

//

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// modification, are permitted provided that the following conditions 

// are met:

// 

// 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 

// documentation and/or other materials provided with the 

// distribution.

// 

// Neither the name of Texas Instruments Incorporated nor the names of

// its contributors may be used to endorse or promote products derived

// from this software without specific prior written permission.

// 

// 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

// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 

// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 

// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 

// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 

// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 

// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

// $

//#############################################################################

//

​

//

// Included Files

//

#include "driverlib.h"

#include "device.h"

​

//

// Defines

//

#define RESULTS_BUFFER_SIZE 256

#define EX_ADC_RESOLUTION 12 //분해능 능력, single ended 모드, VREFLO 가 low이다.

// 12 for 12-bit conversion resolution, which supports (ADC_MODE_SINGLE_ENDED)

// Sample on single pin (VREFLO is the low reference)

// Or 16 for 16-bit conversion resolution, which supports (ADC_MODE_DIFFERENTIAL)

// Sample on pair of pins (difference between pins is converted, subject to

// common mode voltage requirements; see the device data manual)

​

//

// Globals

//

uint16_t adcAResults[RESULTS_BUFFER_SIZE]; // Buffer for results

uint16_t adcReal[RESULTS_BUFFER_SIZE];

uint16_t index; // Index into result buffer

volatile uint16_t bufferFull; // Flag to indicate buffer is full

long a;

//

// Function Prototypes

//

void initADC(void);

void initEPWM(void);

void initADCSOC(void);

__interrupt void adcA1ISR(void);

​

int BackTicker = 0;

int IrsTicker = 0;

//

// Main

//

void main(void)

{

//

// Initialize device clock and peripherals

//

Device_init();

​

//

// Disable pin locks and enable internal pullups.

//

Device_initGPIO();

​

//

// Initialize PIE and clear PIE registers. Disables CPU interrupts.

//

Interrupt_initModule();

​

//

// Initialize the PIE vector table with pointers to the shell Interrupt

// Service Routines (ISR).

//

Interrupt_initVectorTable();

​

//

// Interrupts that are used in this example are re-mapped to ISR functions

// found within this file.

//

Interrupt_register(INT_ADCA1, &adcA1ISR);

​

//

// Set up the ADC and the ePWM and initialize the SOC

//

initADC();

initEPWM();

initADCSOC();

​

//

// Initialize results buffer

//

for(index = 0; index < RESULTS_BUFFER_SIZE; index++)

{

adcAResults[index] = 0;

adcReal[index] = 0;

}

​

index = 0;

bufferFull = 0;

​

//

// Enable ADC interrupt

//

Interrupt_enable(INT_ADCA1);

​

//

// Enable Global Interrupt (INTM) and realtime interrupt (DBGM)

//

EINT;

ERTM;

​

//

// Loop indefinitely

//

while(1)

{

BackTicker++;//무한 루프 발생 횟수 측정

//

// Start ePWM1, enabling SOCA and putting the counter in up-count mode

// 변환하는 모드랑, 어떤 모드 쓸지..이건 좀 더 공부 필요

EPWM_enableADCTrigger(EPWM1_BASE, EPWM_SOC_A);

EPWM_setTimeBaseCounterMode(EPWM1_BASE, EPWM_COUNTER_MODE_UP);

​

//

// Wait while ePWM1 causes ADC conversions which then cause interrupts.

// When the results buffer is filled, the bufferFull flag will be set.

//

while(bufferFull == 0)

{

}

bufferFull = 0; // Clear the buffer full flag

​

//

// Stop ePWM1, disabling SOCA and freezing the counter

//

EPWM_disableADCTrigger(EPWM1_BASE, EPWM_SOC_A);

EPWM_setTimeBaseCounterMode(EPWM1_BASE, EPWM_COUNTER_MODE_STOP_FREEZE);

​

//

// Software breakpoint. At this point, conversion results are stored in

// adcAResults.

//

// Hit run again to get updated conversions.

//

// ESTOP0;

}

}

​

//

// Function to configure and power up ADCA.

//

void initADC(void)

{

​

//

// Set ADCDLK divider to /4

// 4분주 사용, 200Mhz(system clock)/2(based 분주)/4(ADC 분주) = 25Mhz

ADC_setPrescaler(ADCA_BASE, ADC_CLK_DIV_4_0);

​

//

// Set resolution and signal mode (see #defines above) and load

// corresponding trims.

//

#if(EX_ADC_RESOLUTION == 12) // 12분주로 위에 이미 선택함

ADC_setMode(ADCA_BASE, ADC_RESOLUTION_12BIT, ADC_MODE_SINGLE_ENDED);

#elif(EX_ADC_RESOLUTION == 16)

ADC_setMode(ADCA_BASE, ADC_RESOLUTION_16BIT, ADC_MODE_DIFFERENTIAL);

#endif

​

//

// Set pulse positions to late

// 변환후 인터럽트 발생

ADC_setInterruptPulseMode(ADCA_BASE, ADC_PULSE_END_OF_CONV);

​

//

// Power up the ADC and then delay for 1 ms

// 아래 두갠 무조건 들어가야 하는 것임, 그냥 전력 넣어주고 딜레이 걸어 준다고 생각하렴

ADC_enableConverter(ADCA_BASE);

DEVICE_DELAY_US(1000);

}

​

//

// Function to configure ePWM1 to generate the SOC.

//

void initEPWM(void)

{

//

// Disable SOCA

//

EPWM_disableADCTrigger(EPWM1_BASE, EPWM_SOC_A);

​

//

// Configure the SOC to occur on the first up-count event

//

EPWM_setADCTriggerSource(EPWM1_BASE, EPWM_SOC_A, EPWM_SOC_TBCTR_U_CMPA);

EPWM_setADCTriggerEventPrescale(EPWM1_BASE, EPWM_SOC_A, 1);

​

//

// Set the compare A value to 1000 and the period to 1999

// Assuming ePWM clock is 100MHz, this would give 50kHz sampling

// 50MHz ePWM clock would give 25kHz sampling, etc. 

// The sample rate can also be modulated by changing the ePWM period

// directly (ensure that the compare A value is less than the period). 

//

EPWM_setCounterCompareValue(EPWM1_BASE, EPWM_COUNTER_COMPARE_A, 1000);

EPWM_setTimeBasePeriod(EPWM1_BASE, 1999);

​

//

// Set the local ePWM module clock divider to /1

//

EPWM_setClockPrescaler(EPWM1_BASE,

EPWM_CLOCK_DIVIDER_1,

EPWM_HSCLOCK_DIVIDER_1);

​

//

// Freeze the counter

//

EPWM_setTimeBaseCounterMode(EPWM1_BASE, EPWM_COUNTER_MODE_STOP_FREEZE);

}

​

//

// Function to configure ADCA's SOC0 to be triggered by ePWM1.

//

void initADCSOC(void)

{

//

// Configure SOC0 of ADCA to convert pin A0. The EPWM1SOCA signal will be

// the trigger.

// - For 12-bit resolution, a sampling window of 15 (75 ns at a 200MHz

// SYSCLK rate) will be used. For 16-bit resolution, a sampling window

// of 64 (320 ns at a 200MHz SYSCLK rate) will be used.

// - NOTE: A longer sampling window will be required if the ADC driving

// source is less than ideal (an ideal source would be a high bandwidth

// op-amp with a small series resistance). See TI application report

// SPRACT6 for guidance on ADC driver design.

//

​

#if(EX_ADC_RESOLUTION == 12)

ADC_setupSOC(ADCA_BASE, ADC_SOC_NUMBER0, ADC_TRIGGER_EPWM1_SOCA,

ADC_CH_ADCIN0, 15);

#elif(EX_ADC_RESOLUTION == 16)

ADC_setupSOC(ADCA_BASE, ADC_SOC_NUMBER0, ADC_TRIGGER_EPWM1_SOCA,

ADC_CH_ADCIN0, 64);

#endif

​

//

// Set SOC0 to set the interrupt 1 flag. Enable the interrupt and make

// sure its flag is cleared.

//

ADC_setInterruptSource(ADCA_BASE, ADC_INT_NUMBER1, ADC_SOC_NUMBER0);

ADC_enableInterrupt(ADCA_BASE, ADC_INT_NUMBER1);

ADC_clearInterruptStatus(ADCA_BASE, ADC_INT_NUMBER1);

}

​

//

// ADC A Interrupt 1 ISR

//

__interrupt void adcA1ISR(void)

{

IrsTicker++;

//

// Add the latest result to the buffer

//

adcAResults[index] = ADC_readResult(ADCARESULT_BASE, ADC_SOC_NUMBER0);

adcReal[index] = adcAResults[index]/4096*3;

index++;

//

// Set the bufferFull flag if the buffer is full

//

if(RESULTS_BUFFER_SIZE <= index)

{

index = 0;

bufferFull = 1;

}

​

//

// Clear the interrupt flag

//

ADC_clearInterruptStatus(ADCA_BASE, ADC_INT_NUMBER1);

​

//

// Check if overflow has occurred

//

if(true == ADC_getInterruptOverflowStatus(ADCA_BASE, ADC_INT_NUMBER1))

{

ADC_clearInterruptOverflowStatus(ADCA_BASE, ADC_INT_NUMBER1);

ADC_clearInterruptStatus(ADCA_BASE, ADC_INT_NUMBER1);

}

​

//

// Acknowledge the interrupt

//

Interrupt_clearACKGroup(INTERRUPT_ACK_GROUP1);

}