[SOLVED] ADC problem using PIC16F876A

[papunblg]

The following code (to measure voltage using inbuilt ADC) is not working as expected. It appears that AN0 is not accepting input. Am I missing something? (for the time being I am using ADC0804 with 16f876A!!!!!!!!!as I am pretty comfortable with it)

void main(void)
{
ADCON0=0b10000000;
ADCON1=0b11000000;
ADCON0.ADON=1; // turn on the A2D conversion module
Delay_ms(300);
LCD_init();
while(1){
Delay_ms(300);
read_adc();
-----
-------
}

void read_adc(void)
{
unsigned short result;
ADCON0.GO = 1; //ADC start
while(ADCON0.GO==1);
result=ADRESH;
result=result<<8; //shift to left for 8 bit
result=result|ADRESL; //10 bit result from ADC
}

 

[engshahrul]

Did you set RA0 as input?

TRISA0=1;

 

[bjuric]

unsigned short result;

Short is 1 byte long. You need at least int size (2B).

result=result<<8; //shift to left for 8 bit

After this, result = 0

Also the scope of the result is inside the block. You should use "return result;", or a global variable.

 

[papunblg]

Thanks Mr. bjuric. Its working now