ADC conversion using AVR

[gameelgamal]

avr adc

HI,
I tried to perform AD conversion using ATMEGA16 & code vision compiler
but it doesnt work!!!

I need any ADC example to compare my progam with it..

 

[budhy]

avr adc speed

Use CodeWizardAVR (shift+F2) inside CodeVision to build your ADC code! It worked

 

[yogi]

adc_vref_type

below link will give you the ADC code for WinAVR
**broken link removed**

Bibin John
www.bibinjohn.tk

 

[xave1200]

adc avr

Use the 3 ADC register in ATMega16
ADMUX, ADCSRA, and SFIOR.

Or, if you want to use the CodeWizardAVR, u can use it anyway.
Just be sure you are using free running ADC or single run ADC.

 

[member_tdh]

avr adc registers

/*****************************************************
Project : Board Test
Version : 1.0
Date : 2/25/2007

Chip type : ATmega8535
Program type : Application
Clock frequency : 4.000000 MHz
Memory model : Small
External SRAM size : 0
Data Stack size : 128
*****************************************************/

#include <mega8535.h>
#include "stdio.h"
#include "realtime.h"
#include "delay.h"
#include "eeprom.h"

#define ADC_VREF_TYPE 0x40

// Read the AD conversion result
unsigned int read_adc(unsigned char adc_input)
{
ADMUX=adc_input|ADC_VREF_TYPE;
// Start the AD conversion
ADCSRA|=0x40;
// Wait for the AD conversion to complete
while ((ADCSRA & 0x10)==0);
ADCSRA|=0x10;
return ADCW;
}

void Init()
{

// ADC initialization
// ADC Clock frequency: 125.000 kHz
// ADC Voltage Reference: AVCC pin
// ADC High Speed Mode: Off
// ADC Auto Trigger Source: None
ADMUX=ADC_VREF_TYPE;
ADCSRA=0x86;
SFIOR&=0xEF;

}


unsigned int Get_Voltage()
{
unsigned char i;
unsigned int V=0;
unsigned int Data_ADC=0;

buff[4]=buff[3];
buff[3]=buff[2];
buff[2]=buff[1];
buff[1]=buff[0];
buff[0]=read_adc(7);
for(i=0;i<5;i++) Data_ADC+=buff;
V=(unsigned int)((float)Data_ADC/5);
return(V);
}

void main(void)
{

Vadc = Get_Voltage();

}

Good luck to YOU!

 

[senthilkumar]

avr +adc

use Image Craft Wizard

 

[maggots]

how to use avr adc

i hope this will help U..

i use atmega32 ..adc 8 bits... and make sampling 8 times ... for display result of adc conversion i use lcd 16

#include <mega32.h>

// Alphanumeric LCD Module functions
#asm
.equ __lcd_port=0x15 ;PORTC
#endasm
#include <lcd.h>
#include <delay.h>
#include <math.h>
#include <stdio.h>

// Declare your global variables here
char Str[16];
unsigned char adc_input;
unsigned int i;
unsigned char data_adc;
unsigned char data_tampung[8];
unsigned int jumlah;
unsigned int rata2;
unsigned char data_final;

// Read the 8 most significant bits
// of the AD conversion result
unsigned char read_adc(unsigned char adc_input)
{
ADMUX=adc_input|ADC_VREF_TYPE;
for(i=0 ; i<8; i++)
{

// Start the AD conversion
ADCSRA|=0x40;
// Wait for the AD conversion to complete
while ((ADCSRA & 0x10)==0);
ADCSRA|=0x10;
//return ADCH;
data_adc = ADCH;
data_tampung= data_adc;

}

jumlah = 0;
for(i =0 ;i<8;i++)
{
jumlah += data_tampung;
}

rata2 = ceil(jumlah/8);
data_final =(unsigned char)rata2;
return data_final;
}

void main(void)
{
// Declare your local variables here
unsigned int a= 0;
unsigned char data_kiri;
unsigned char data_serong1;



// Input/Output Ports initialization
// Port A initialization
PORTA=0x00;
DDRA=0x00;

// Port B initialization
PORTB=0x00;
DDRB=0xFF;//port output OKKK

// Port C initialization
PORTC=0x00;
DDRC=0xFF;

// Port D initialization
PORTD=0x00;
DDRD=0xFF;

// Timer/Counter 0 initialization
// Clock source: System Clock
// Clock value: 16000,000 kHz
// Mode: Normal top=FFh
// OC0 output: Disconnected
TCCR0=0x01;
TCNT0=0x00;
OCR0=0x00;

// Timer/Counter 1 initialization
// Clock source: System Clock
// Clock value: Timer 1 Stopped
// Mode: Normal top=FFFFh
// OC1A output: Discon.
// OC1B output: Discon.
// Noise Canceler: Off
// Input Capture on Falling Edge
// Timer 1 Overflow Interrupt: Off
// Input Capture Interrupt: Off
// Compare A Match Interrupt: Off
// Compare B Match Interrupt: Off

TCNT1H=0x00;
TCNT1L=0x00;
ICR1H=0x00;
ICR1L=0x00;
OCR1AH=0x00;
OCR1AL=0x00;
OCR1BH=0x00;
OCR1BL=0x00;

// Timer/Counter 2 initialization
// Clock source: System Clock
// Clock value: Timer 2 Stopped
// Mode: Normal top=FFh
// OC2 output: Disconnected
ASSR=0x00;
TCCR2=0x00;
TCNT2=0x00;
OCR2=0x00;

// External Interrupt(s) initialization
// INT0: Off
// INT1: Off
// INT2: Off
MCUCR=0x00;
MCUCSR=0x00;

// Timer(s)/Counter(s) Interrupt(s) initialization
TIMSK=0x00;

// Analog Comparator initialization
// Analog Comparator: Off
// Analog Comparator Input Capture by Timer/Counter 1: Off
ACSR=0x80;
SFIOR=0x00;

// ADC initialization
// ADC Clock frequency: 500,000 kHz
// ADC Voltage Reference: AREF pin
// Only the 8 most significant bits of
// the AD conversion result are used
ADMUX=ADC_VREF_TYPE;
ADCSRA=0x85;

// LCD module initialization
lcd_init(16);
lcd_clear();
lcd_gotoxy(0,0);
sprintf(Str," start ");
lcd_puts(Str);

while(1)
{

read_adc(3);
data_conversion = data_final;

lcd_clear();
lcd_gotoxy(0,0);
sprintf(Str,"data conversion= %u",data_conversion);
lcd_puts(Str);

};

 

[nipun]

read_adc avr

all the codes given in different are ok but did connect external capacitor btwn AREF and GND try that.

 

[deepakgupta.rf]

Re: how to use avr adc

hello sir
thanks for this code
i m using atmega32 and mq6 gas sensor and connecting tis one pin to pina.0 and taking its analog value and aref=avcc and when i see value at lcd then the value convert but it usually show a value256 and then decrement one by one and when i open gas then show a value and again decrement value on by one.
so sir plz help me in that

 

[volka123456]

Re: avr adc registers

/*****************************************************
Project : Board Test
Version : 1.0
Date : 2/25/2007

Chip type : ATmega8535
Program type : Application
Clock frequency : 4.000000 MHz
Memory model : Small
External SRAM size : 0
Data Stack size : 128
*****************************************************/

#include <mega8535.h>
#include "stdio.h"
#include "realtime.h"
#include "delay.h"
#include "eeprom.h"

#define ADC_VREF_TYPE 0x40

// Read the AD conversion result
unsigned int read_adc(unsigned char adc_input)
{
ADMUX=adc_input|ADC_VREF_TYPE;
// Start the AD conversion
ADCSRA|=0x40;
// Wait for the AD conversion to complete
while ((ADCSRA & 0x10)==0);
ADCSRA|=0x10;
return ADCW;
}

void Init()
{

// ADC initialization
// ADC Clock frequency: 125.000 kHz
// ADC Voltage Reference: AVCC pin
// ADC High Speed Mode: Off
// ADC Auto Trigger Source: None
ADMUX=ADC_VREF_TYPE;
ADCSRA=0x86;
SFIOR&=0xEF;

}


unsigned int Get_Voltage()
{
unsigned char i;
unsigned int V=0;
unsigned int Data_ADC=0;

buff[4]=buff[3];
buff[3]=buff[2];
buff[2]=buff[1];
buff[1]=buff[0];
buff[0]=read_adc(7);
for(i=0;i<5;i++) Data_ADC+=buff;
V=(unsigned int)((float)Data_ADC/5);
return(V);
}

void main(void)
{

Vadc = Get_Voltage();

}

Good luck to YOU!

Hi Sir,

How can i read ADC by use interrupt ADC???

Thanks you,