Components Required
- ATmega32 microcontroller
- AVR Programmer Board
- Crystal
- Capacitors
- LEDs
- +5V supply
- Breadboard
- Connecting Wires
Circuit Diagram
Description
The digital value of the analog input at PA0 will be shown in the 8 leds PC0 to PC7 from LSB to MSB.
Connections
- LEDs are connected to the Pins 0 to 7 of PORT C.
- The analog input is given to PIN A0 (ADC 0).
- A crystal is connected to the XTAL1 and XTAL2 pins to provide the clock pulse.
- Reset is connected to +5V.
Source Code
/*The following code will keep on converting the analog value applied at the pin PA0, convert it into digital value and store the most significant 8 bits in ADCH register and the lesser two bits in the ADCL register.
Since the lesser two values can be ignored the 8 bits present in the ADCH are only taken care of and the LEDs are glown according to the ADCH register*/
/* Go through the blog http://rickruling.blogspot.in/2013/10/adc-control-and-status-registers.html for more details on adc control and status registers*/
#include <avr/io.h>
#include <avr/interrupt.h> //For interrupt handling
#ifndef F_CPU
#define F_CPU 1000000UL //frequency of the external crystal
#endif
int main(void)
{
DDRC = 0xFF; //All ports of port C as output
PORTB = 0x00; //Initially all pins as output low
//configure the ADC
ADCSRA |=1<<ADPS2; //ADC Prescaler Select Bits (Division Factor is 16 for 100)
ADMUX |=1<<ADLAR; //MSB in ADCH
ADMUX |=1<<REFS0; // AREF pin
ADCSRA |=1<<ADIE; //ADC Interrupt Enable
ADCSRA |=1<<ADEN; //ADC Enable
sei(); //set global interrupt enable
ADCSRA |=1<<ADSC; //ADC Start Conversion
while(1) //Infinite loop
;
}
ISR(ADC_vect)
{
PORTB = ADCH; //Result of conversion to PORTB
ADCSRA |=1<<ADSC; //Restart the conversion
}
Thank you for reading.
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