ADC 16f877 code beginner help

[maria258]

i am new using microcontrollers. at the moment im starting using 16f877 and need to start by programming the adc (10 bit). all i did for now is the code shown below. is it enough to read data? or does it need alteration?
i am using mplab to compile and proteus for schematics.
thanks
maria



#include <htc.h>
#include <pic.h>

unsigned int data;

void main(void)
{
//configuring input/outputs
PORTA = 0x00;
TRISA = 0xFF;
TRISB = 0x00;

//configuring ADC
ADCON0=0b00000001 //setting ADON on
ADCON1=0b10000000 //ADFM is set right


while(1)
{
ADCON0|= GODONE; //start conversion
{
break
}

if (ADRESH == 1)
{
data = ADRESL + 256;
}
else if (ADRESH == 2)
{
data = ADRESL + 512;
}
else if (ADRESH == 3)
{
data = ADRESL + 768;
}
else if (ADRESH == 0)
{
data = ADRESL;
}
}
}

 

[Pommie]

You don't mention what speed your chip will be running at and so the value for Fosc division is unknown. To be safe set it to Fosc/32. You also don't need to combine the registers the way you have it, you can do it like,

void main(void){
    //configuring input/outputs
    PORTA = 0x00;
    TRISA = 0xFF;
    TRISB = 0x00;
    
    //configuring ADC
    ADCON0=0b10000001 //setting ADON on and Fosc/32
    ADCON1=0b11000000 //ADFM is set right and Fosc/32
    while(1){
        GODONE=1;		//start conversion
        while(GODONE);		//wait for it to complete
        data=ADRESH*256+ADRESL;	//get answer
    }
}

Note, you have to wait for the conversion to complete.

You will also need to set a config value to use it in an actual chip.

Also, when posting code use the code tags or type [code] before it and [/code] after it.

Mike.