Timer

Functions
int	tim1_PWM_init (void)
	Initialize Timer1 for Fast PWM on OC1A.
int	tim1_CTC_init (void)
	Initialize Timer1 in CTC mode on OC1A.

Detailed Description

Function Documentation

tim1_CTC_init()

int tim1_CTC_init

(

void

)

#include <timer.h>

Initialize Timer1 in CTC mode on OC1A.

Configures PD5 as output and sets up CTC toggling with a compare value that yields roughly 1–1.2 MHz output depending on clock and prescaler.

Returns

0 on success.

Definition at line 26 of file timer.c.

                        {
  // Set OC1A on PD5 as output
  DDRD |= (1 << PD5);
 
  // CTC mode, toggle OC1A on compare
  TCCR1A = (1 << COM1A0);
  TCCR1B = (1 << WGM12) | (1 << CS10);
 
  OCR1AL = 0x01; // Compare value
  OCR1AH = 0x01 >> 8;
  // With 4915200 Hz clk, N=8, value =  4915200/(2*8*(1+f_desierd)) = 1 MHz
  // 1 = ~1.23Mhz
 
  return 0;
}

Referenced by main().

tim1_PWM_init()

int tim1_PWM_init

(

void

)

#include <timer.h>

Initialize Timer1 for Fast PWM on OC1A.

Configures PD5 as output, sets Fast PWM mode with ICR1 as top, and generates ~50% duty cycle at approximately 983 kHz (with ICR1 = 4).

Returns

0 on success.

Definition at line 6 of file timer.c.

                        {
  // Set OC1A on PD5 as output
  DDRD |= (1 << PD5);
 
  // Fast PWM,
  // Set Compare Output Mode
  TCCR1A = (1 << COM1A1);
  // Set Clock to PWM fast mode, and prescaler 10(CS10)
  TCCR1B = (1 << WGM13) | (1 << WGM12) | (1 << CS10);
  TCCR1A |= (1 << WGM11);
 
  ICR1L = 0x04; // frequency = fclk/(N*(1+ICR1)) 4 ~983khz
  ICR1H = ((0x04) >> 8);
  OCR1AL = 0x04 / 2; // 50% duty cycle
  OCR1AH = (0x04 / 2 >> 8);
 
  return 0;
}