[General] Problems in reading ADC in PIC18

[imran090]

Hi all,


I am new to the pic programming...can anyone tell me how to calculate voltage in pic..?

I am using PIC18F85J11.. I want to read 3 channels ( AN0,AN1 & AN4 ). I have tried to read the values, but I am getting some junk values.

Thank You

View attachment adc.txt

 

[wizpic]

You need to post your code as no one will be able to help as we don't know your setup and what language your using opps sorry did not see the attachment must have been one to many beers :grin:

 

[imran090]

Hi

Below is my code..

// Header Files
#include <p18cxxx.h>
#include <stdio.h>

// Configuration Bit Settings
#pragma config FOSC = HSPLL,DEBUG = ON, WDTEN = OFF, XINST = OFF


void adc_init();
void ADC_value();
unsigned int ADCRead_ch0();
unsigned int ADCRead_ch1();
unsigned int ADCRead_ch4();
void DelayFor18TCY();
void Read_ADC_All_Segments();

unsigned int adc_value,adc_value_1,adc_value_2;
unsigned int a0 = 0;
unsigned int a1 = 0;
unsigned int a4 = 0;
unsigned int val_0 ;
unsigned int val_1 ;
unsigned int val_4 ;

main
{
adc_init();

while(1)
{
Read_ADC_All_Segments();
}
}


// Delay Function
{
Delay10TCYx(20);
}

// ADC initialisation
void adc_init()
{
ADCON1bits.VCFG1 = 0;
ADCON1bits.VCFG0 = 0;
ADCON1bits.PCFG = 0b1010;
ADCON2bits.ADFM = 1;
ADCON2bits.ACQT = 0b010;
ADCON2bits.ADCS = 0b0010;
}

// Copying ADRESH and ADRESL
void ADC_value()
{
adc_value = ADRESH;
adc_value_1 = ADRESL;
adc_value = adc_value << 8;
adc_value_2 = adc_value | adc_value_1;
}

// Reading channel 0
unsigned int ADCRead_ch0()
{
ADCON0 = 0x04;
ADCON0bits.ADON = 1;
ADCON0bits.GO_DONE = 1;
while(ADCON0bits.GO_DONE);
ADC_value();
a0 = adc_value_2;
return a0;
}

// Reading channel 1
unsigned int ADCRead_ch1( )
{
ADCON0 = 0x00;
ADCON0bits.ADON = 1;
ADCON0bits.GO_DONE = 1;
while(ADCON0bits.GO_DONE);
ADC_value();
a1 = adc_value_2;
return a1;
}

// Reading channel 4
unsigned int ADCRead_ch4( )
{
ADCON0 = 0x10;
ADCON0bits.ADON = 1;
ADCON0bits.GO_DONE = 1;
while(ADCON0bits.GO_DONE);
ADC_value();
a4 = adc_value_2;
return a4;
}


void Read_ADC_All_Segments(void)
{
val_0 = ADCRead_ch0();
DelayFor18TCY();

val_1 = ADCRead_ch1( );
DelayFor18TCY();

val_4 = ADCRead_ch4();
DelayFor18TCY();
}


Thank you