From OmgaV Wiki

SIRC Transmitter

This code can be used to transmit data to an IR receiver, for example a TV or DVD player. It has been setup for the Butterfly (ATmega169), but can be used with any AVR.

sirc.c

#include <avr/io.h>
#include <util/delay_basic.h>
 
#define UTPORT PORTD
#define UTDDR DDRD
#define UTPIN PD0
 
//Transmit Sony Ir Code (SIRC)
//Based on http://users.pandora.be/davshomepage/
//Designed for ATmega 169 @ 8Mhz
 
void sendBit(unsigned char bit);
void sendIR(char adr, char cmd);
 
int main(void){
	UTDDR |= (1<<UTPIN);
 
	while(1){
		for(char i=64; i<71; i++){
			sendIR(0b00001, i);
		}
	}
}
 
 
 
void sendIR(char adr, char cmd){
	sendBit(3);
 
	sendBit((cmd>>0) & 1);
	sendBit((cmd>>1) & 1);
	sendBit((cmd>>2) & 1);
	sendBit((cmd>>3) & 1);
	sendBit((cmd>>4) & 1);
	sendBit((cmd>>5) & 1);
	sendBit((cmd>>6) & 1);
 
 
	sendBit((adr>>0) & 1);
	sendBit((adr>>1) & 1);
	sendBit((adr>>2) & 1);
	sendBit((adr>>3) & 1);
	sendBit((adr>>4) & 1);
 
	//Wait 40ms
	_delay_loop_2(61000);
	_delay_loop_2(15923);
}
 
void sendBit(unsigned char bit){
	char length = 20*(bit+1);
	UTPORT &= ~(1<<UTPIN);
	_delay_loop_2(1200); //Wait 4000 clock cycles
	for(char i = 0; i<length; i++){
		UTPORT |= (1<<UTPIN);
		_delay_loop_2(30); //Wait 100 clock cycles
		UTPORT &= ~(1<<UTPIN);
		_delay_loop_2(30); //Wait 100 clock cycles
	}	
}