Please help me with code for using in built adc of atmega32. Its urgent. Thanks alot

[techspark]

the program is not running properly I tried it in proteus and used winavr.
the code takes the analog value from port a and gives the output to port b.
code as follows:


#include<avr/io.h>
#include<util/delay.h>

void ADC_init(void);
unsigned int ADC_read(unsigned char);

// ------------------------------------------------
int main(void)
{
unsigned int value;
DDRB=0xFF;
DDRA=0x00;
ADC_init(); // Initialization of ADC
// ch=0;
while(1)
{
value=ADC_read(0);
PORTB=value;
_delay_us(500);
}
}
//------------------------------------------------

void ADC_init(void) // Initialization of ADC
{
ADMUX=(1<<REFS0)|(1 << ADLAR); // AVcc with external capacitor at AREF
ADCSRA=(1<<ADEN)|(1<<ADPS2)|(1<<ADPS1)|(1<<ADPS0);
SFIOR=(1<<PUD); // Enable ADC and set Prescaler division factor as 128 & also disabling the pull ups
}

unsigned int ADC_read(unsigned char ch)
{
ch= ch & 0b00000111; // channel must be b/w 0 to 7
ADMUX |= ch; // selecting channel
ADCSRA|=(1<<ADSC)| (1 << ADEN); // start conversion
while(!(ADCSRA & (1<<ADIF))); // waiting for ADIF, conversion complete
ADCSRA|=(1<<ADIF); // clearing of ADIF, it is done by writing 1 to it

return (ADC);
}

 

[per_lube]

Did you use the proper microcontroller in Proteus or winavr?

Please make sure whether you are setting proper values for the registers such as DDRB, DDRA, ADMUX etc.

 

[alexxx]

You are not giving details on the exact problem, making it hard to focus on something specific in order to spot the mistake.
After a quick view, the problem may lie on the fact that you are reading on a 16 bit variable ('"value" as it is named inside the code) from the adc, but you are driving this value to PORTB which has 8 pins. The ADC result is left adjusted (ADLAR=1), which means that only the lower 8 bits of the ADC reg will be passed to port pins. Those bits contain only the lower two bits of the of the conversion, page 217.

http://www.atmel.com/Images/doc2503.pdf

I don't know if this solves it, maybe you should provide more info on the problem.