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Electronics => Electronics => Topic started by: Karlis.Rasis on March 22, 2012, 06:24:21 AM

Title: Control 4 servos with differenet timers in Atmega16?
Post by: Karlis.Rasis on March 22, 2012, 06:24:21 AM

HI! Question is, can Atmega16 control 4 servos with different timers?
Two servos are continuous rotation and two are normal 180 degrees.
Datasheet says that MCU have Two 8-bit Timer and One 16-bit timer.
180 degrees servos are connected to (OC1B)- PD4 and (OC1A)-PD5.
But where I can connect other two continuous rotation servos? How to activate other timers?

Code: [Select]

void main()
{
   //Configure TIMER1
   TCCR1A|=(1<<COM1A1)|(1<<COM1B1)|(1<<WGM11);        //NON Inverted PWM
   TCCR1B|=(1<<WGM13)|(1<<WGM12)|(1<<CS11)|(1<<CS10); //PRESCALER=64 MODE 14(FAST PWM)

   ICR1=4999;  //fPWM=50Hz (Period = 20ms Standard).

   DDRD|=(1<<PD4)|(1<<PD5);   //PWM Pins as Out

   while(1)
   {

      OCR1A=316;  //90 degree
      OCR1B=316;  //90 degree

   }
}If I connect them to PB0 and PB1 and  write this code

Code: [Select]

           PORTB =  0b00000000;
       _delay_ms(0.7);
    PORTB = 0b00000001;
       _delay_ms(0.7);
   PORTB =  0b00000000;
       _delay_ms(0.7);
    PORTB = 0b00000010;
to main() {...} servos rotate incorect, and I guess that I need another timer or way to control them.
Have any Ideas?  ???

Title: Re: Control 4 servos with differenet timers in Atmega16?
Post by: joe61 on March 22, 2012, 07:59:58 AM

Atmel has an application note about this with source code. Look at http://www.atmel.com/products/microcontrollers/avr/default.aspx?tab=documents (http://www.atmel.com/products/microcontrollers/avr/default.aspx?tab=documents) and search for AVR136. The .pdf is the icon on the left, and the little circle icon that looks like a CD is the source code archive.

It works pretty well.

Joe

Title: Re: Control 4 servos with differenet timers in Atmega16?
Post by: Soeren on March 22, 2012, 07:37:47 PM

Hi,

Quote from: Karlis.Rasis on March 22, 2012, 06:24:21 AM

HI! Question is, can Atmega16 control 4 servos with different timers?

One timer will do, but please post software questions in "Software"!

Title: Re: Control 4 servos with differenet timers in Atmega16?
Post by: Karlis.Rasis on March 25, 2012, 05:28:45 AM

I found simple way how to control 4 servos with 3 different timers on ATmega16!

Code: [Select]

int main(void)
{ 
 //Initialize OC0-pin B3, OC2-pin D7, OC1A- pin D5,OC1B- pin D4.
   TCCR0 = (1<<WGM00) | (1<<COM01) | (1<<CS02) | (1<<CS00);//First 8 bit timer
   TCCR2 = (1<<WGM20) | (1<<COM21) | (1<<CS22) | (1<<CS20); //Second 8 bit timer
   TCCR1A|=(1<<COM1A1)|(1<<COM1B1)|(1<<WGM11);  //third 16bit timer
   TCCR1B|=(1<<WGM13)|(1<<WGM12)|(1<<CS11)|(1<<CS10); ////third 16bit timer

   //Setting ports as output
   DDRB|=(1<<PB3);//PWM Pins as Out
   DDRD|=(1<<PD7);//PWM Pins as Out
   DDRD|=(1<<PD5);//PWM Pins as Out
   DDRD|=(1<<PD4);//PWM Pins as Out

OCR0=1;//Set first servo
OCR2=100;//Set second servo
OCR1A = 150;//Set third servo
OCR1B = 80;//Set fourth servo

}