Quote from Ricardo Kersckbaumer on May 7, 2024, 5:25 pm

I set up a very simple circuit, just an LED on pin A0. For this circuit I made a software that uses timer 0 to change the state of the A0 output at 1 ms intervals. The output remains at 0. I changed the code to use timer 1, and the output alternated, but very slowly, at 0.5s intervals. I changed the program again, this time to timer 2, and the output now remains at 0.

To check my programs I used a real microcontroller, and all three programs worked properly.

So, as in a real circuit my programs work and in the ATMega32 simulated with the simulide they don't work, I believe there is some problem with the ATMega32 timers in the simulator.

The circuit is only an ATMega32 running at 8 MHz with a resistor and an LED connected to pin 40 (A0).

These are the programs used:

For Timer 0:

#include <avr/io.h>
#include <avr/interrupt.h>

// Define the LED pin
#define LED_PIN     PA0

// Initialize Timer 0 to generate an interrupt every 1 ms
void timer0_init() {
	// Timer 0 Configuration
	TCCR0 |= (1 << WGM01) | (1 << CS01) | (1 << CS00);  // CTC Mode, Prescaler of 64
	OCR0 = 124;  // Value for 1 ms with prescaler of 64 and 8 MHz clock
	TIMSK |= (1 << OCIE0);  // Enable Timer 0 compare match interrupt
}

// Interrupt service routine for Timer 0
ISR(TIMER0_COMP_vect) {
	// Toggle the state of the LED connected to pin PORTA0
	PORTA ^= (1 << LED_PIN);
}

int main(void) {
	// Configure the LED pin as output
	DDRA |= (1 << LED_PIN);

	// Initialize Timer 0
	timer0_init();

	// Enable global interrupts
	sei();

	// Infinite loop
	while (1) {
		// Additional code in the main loop can be added here
	}

	return 0;
}

For Timer 1:

#include <avr/io.h>
#include <avr/interrupt.h>

// Define the LED pin
#define LED_PIN     PA0

// Initialize Timer 1 to generate an interrupt every 1 ms
void timer1_init() {
	// Timer 1 Configuration
	TCCR1B |= (1 << WGM12) | (1 << CS11) | (1 << CS10);  // CTC Mode, Prescaler of 64
	OCR1A = 124;  // Value for 1 ms with prescaler of 64 and 8 MHz clock
	TIMSK |= (1 << OCIE1A);  // Enable Timer 1 compare match A interrupt
}

// Interrupt service routine for Timer 1
ISR(TIMER1_COMPA_vect) {
	// Toggle the state of the LED connected to pin PORTA0
	PORTA ^= (1 << LED_PIN);
}

int main(void) {
	// Configure the LED pin as output
	DDRA |= (1 << LED_PIN);

	// Initialize Timer 1
	timer1_init();

	// Enable global interrupts
	sei();

	// Infinite loop
	while (1) {
		// Additional code in the main loop can be added here
	}

	return 0;
}

And for Timer 2:

#include <avr/io.h>
#include <avr/interrupt.h>

// Define the LED pin
#define LED_PIN     PA0

// Initialize Timer 2 to generate an interrupt every 1 ms
void timer2_init() {
    // Timer 2 Configuration
    TCCR2 |= (1 << WGM21) | (1 << CS22);  // CTC Mode, Prescaler of 64
    OCR2 = 124;  // Value for 1 ms with prescaler of 64 and 8 MHz clock
    TIMSK |= (1 << OCIE2);  // Enable Timer 2 compare match interrupt
}

// Interrupt service routine for Timer 2
ISR(TIMER2_COMP_vect) {
    // Toggle the state of the LED connected to pin PORTA0
    PORTA ^= (1 << LED_PIN);
}

int main(void) {
    // Configure the LED pin as output
    DDRA |= (1 << LED_PIN);

    // Initialize Timer 2
    timer2_init();

    // Enable global interrupts
    sei();

    // Infinite loop
    while (1) {
        // Additional code in the main loop can be added here
    }

    return 0;
}

I am at your disposal for further clarification. Thank you

#include <avr/io.h>
#include <avr/interrupt.h>

// Define the LED pin
#define LED_PIN     PA0

// Initialize Timer 0 to generate an interrupt every 1 ms
void timer0_init() {
	// Timer 0 Configuration
	TCCR0 |= (1 << WGM01) | (1 << CS01) | (1 << CS00);  // CTC Mode, Prescaler of 64
	OCR0 = 124;  // Value for 1 ms with prescaler of 64 and 8 MHz clock
	TIMSK |= (1 << OCIE0);  // Enable Timer 0 compare match interrupt
}

// Interrupt service routine for Timer 0
ISR(TIMER0_COMP_vect) {
	// Toggle the state of the LED connected to pin PORTA0
	PORTA ^= (1 << LED_PIN);
}

int main(void) {
	// Configure the LED pin as output
	DDRA |= (1 << LED_PIN);

	// Initialize Timer 0
	timer0_init();

	// Enable global interrupts
	sei();

	// Infinite loop
	while (1) {
		// Additional code in the main loop can be added here
	}

	return 0;
}

#include <avr/io.h>
#include <avr/interrupt.h>

// Define the LED pin
#define LED_PIN     PA0

// Initialize Timer 1 to generate an interrupt every 1 ms
void timer1_init() {
	// Timer 1 Configuration
	TCCR1B |= (1 << WGM12) | (1 << CS11) | (1 << CS10);  // CTC Mode, Prescaler of 64
	OCR1A = 124;  // Value for 1 ms with prescaler of 64 and 8 MHz clock
	TIMSK |= (1 << OCIE1A);  // Enable Timer 1 compare match A interrupt
}

// Interrupt service routine for Timer 1
ISR(TIMER1_COMPA_vect) {
	// Toggle the state of the LED connected to pin PORTA0
	PORTA ^= (1 << LED_PIN);
}

int main(void) {
	// Configure the LED pin as output
	DDRA |= (1 << LED_PIN);

	// Initialize Timer 1
	timer1_init();

	// Enable global interrupts
	sei();

	// Infinite loop
	while (1) {
		// Additional code in the main loop can be added here
	}

	return 0;
}

#include <avr/io.h>
#include <avr/interrupt.h>

// Define the LED pin
#define LED_PIN     PA0

// Initialize Timer 2 to generate an interrupt every 1 ms
void timer2_init() {
    // Timer 2 Configuration
    TCCR2 |= (1 << WGM21) | (1 << CS22);  // CTC Mode, Prescaler of 64
    OCR2 = 124;  // Value for 1 ms with prescaler of 64 and 8 MHz clock
    TIMSK |= (1 << OCIE2);  // Enable Timer 2 compare match interrupt
}

// Interrupt service routine for Timer 2
ISR(TIMER2_COMP_vect) {
    // Toggle the state of the LED connected to pin PORTA0
    PORTA ^= (1 << LED_PIN);
}

int main(void) {
    // Configure the LED pin as output
    DDRA |= (1 << LED_PIN);

    // Initialize Timer 2
    timer2_init();

    // Enable global interrupts
    sei();

    // Infinite loop
    while (1) {
        // Additional code in the main loop can be added here
    }

    return 0;
}