Programming: Outputting a PWM (Pulse Width Modulation) on More Than One Pin of the AVR Microcontroller and Multiple Ports

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Programming: Outputting a PWM (Pulse Width Modulation) on More Than One Pin of the AVR Microcontroller and Multiple Ports

Important aspects of outputting to more than one pin are as follows:

- Make sure the pins that will output the PWM are set for output data direction (i.e. DDRB = 0xFF for all PORT B pins output)

- Make sure that the pins will be set high in the interrupt service routine (ISR)

- Add another line within code block of the if (TCNT1>=800 && TCNT1<=2400) and make sure the pin reflect the correct output pin and the number after the TCNT1 >= value is correctly set for the position for that servo on that pin.

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

int main(void)
{
   DDRA |= 0xFF;
   DDRB |= 0xFF;
   DDRD |= 0xFF;

   TCCR1A |= 1<<WGM11;
   TCCR1B |= 1<<WGM12 | 1<<WGM13 | 1<<CS10;
   TIMSK1 |= 1<<OCIE1A;

   sei();
 
   ICR1 = 19999;
 
  
   while(1)
   {
      if (TCNT1 > 700 && TCNT1 < 2500)
      {
         if (TCNT1 >= 2200 && bit_is_set(PORTA,PINA0)) PORTA &= ~(1<<PINA0);  
         if (TCNT1 >= 900 && bit_is_set(PORTA,PINA1)) PORTA &= ~(1<<PINA1);
         if (TCNT1 >= 1200 && bit_is_set(PORTA,PINA2)) PORTA &= ~(1<<PINA2);  
         if (TCNT1 >= 2000 && bit_is_set(PORTA,PINA3)) PORTA &= ~(1<<PINA3);
         if (TCNT1 >= 2200 && bit_is_set(PORTA,PINA4)) PORTA &= ~(1<<PINA4);  
         if (TCNT1 >= 900 && bit_is_set(PORTA,PINA5)) PORTA &= ~(1<<PINA5);
         if (TCNT1 >= 1200 && bit_is_set(PORTA,PINA6)) PORTA &= ~(1<<PINA6);  
         if (TCNT1 > 2000 && bit_is_set(PORTA,PINA7)) PORTA &= ~(1<<PINA7);   

         if (TCNT1 >= 2200 && bit_is_set(PORTB,PINB0)) PORTB &= ~(1<<PINB0);  
         if (TCNT1 >= 900 && bit_is_set(PORTB,PINB1)) PORTB &= ~(1<<PINB1);
         if (TCNT1 >= 1200 && bit_is_set(PORTB,PINB2)) PORTB &= ~(1<<PINB2);  
         if (TCNT1 >= 2000 && bit_is_set(PORTB,PINB3)) PORTB &= ~(1<<PINB3);
         if (TCNT1 >= 2200 && bit_is_set(PORTB,PINB4)) PORTB &= ~(1<<PINB4);  
         if (TCNT1 >= 900 && bit_is_set(PORTB,PINB5)) PORTB &= ~(1<<PINB5);
         if (TCNT1 >= 1200 && bit_is_set(PORTB,PINB6)) PORTB &= ~(1<<PINB6);  
         if (TCNT1 > 2000 && bit_is_set(PORTB,PINB7)) PORTB &= ~(1<<PINB7);
   
         if (TCNT1 >= 2200 && bit_is_set(PORTD,PIND0)) PORTD &= ~(1<<PIND0);  
         if (TCNT1 >= 900 && bit_is_set(PORTD,PIND1)) PORTD &= ~(1<<PIND1);
         if (TCNT1 >= 1200 && bit_is_set(PORTD,PIND2)) PORTD &= ~(1<<PIND2);  
         if (TCNT1 >= 2000 && bit_is_set(PORTD,PIND3)) PORTD &= ~(1<<PIND3);
         if (TCNT1 >= 2200 && bit_is_set(PORTD,PIND4)) PORTD &= ~(1<<PIND4);  
         if (TCNT1 >= 900 && bit_is_set(PORTD,PIND5)) PORTD &= ~(1<<PIND5);
         if (TCNT1 >= 1200 && bit_is_set(PORTD,PIND6)) PORTD &= ~(1<<PIND6);  
         if (TCNT1 > 2000 && bit_is_set(PORTD,PIND7)) PORTD &= ~(1<<PIND7);
      }
   }
}

ISR(TIMER1_COMPA_vect)
{
   PORTA = 0xFF;
   PORTB = 0xFF;
   PORTD = 0xFF;
}

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Programming: Outputting a PWM (Pulse Width Modulation) on More Than One Pin of the AVR Microcontroller and Multiple Ports

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