主程序如下:

/************************************************************
* Program: AVRGCC - RC5 Test
* Comments: RC5 decoder
* target mcu: 8515
***********************************************************/
#include <io.h>
#include <interrupt.h>
#include <signal.h>
#include "lcd.h"

unsigned int heartbeat=0;

// RC5 variables & definitions
#define PRSC1_SELECT 2 // timer CLK/8
#define TRUE 1
#define FALSE 0
#define IRDet bit_is_set(PIND,PD2)
volatile unsigned char RC5RxAddress, RC5RxCommand;
volatile unsigned char RC5Avail=0, RC5Repeat, RC5PhaseErr;

void delay(unsigned int p)
{
unsigned int i;
unsigned char j;
for(i=0;i<p;i++)
for (j=0;j<100;j++);
}

/* signal handler for timer1 overflow interrupt */
SIGNAL(SIG_OVERFLOW1)
{
static unsigned char RC5BitCnt=0;
static unsigned int RC5Data;
static unsigned char OldValue;
static unsigned char ControlBit;

// Load Timer again...
outp(0xFC, TCNT1H); // set TCNT1 // 889us
outp(0x87, TCNT1L); // set TCNT1

if (RC5BitCnt==0) {
RC5Data=0;
OldValue=IRDet;
RC5PhaseErr=FALSE;
}

if (RC5BitCnt<24) { // sample 24 bits
if (RC5BitCnt & 0x01) {
if (OldValue!=IRDet) { // check for Biphase error
RC5Data <<= 1; // next bit;
if (IRDet) RC5Data &= 0xFFFE; else RC5Data |= 0x0001;
} else RC5PhaseErr=TRUE; // biphase error
}
RC5BitCnt++;
OldValue=IRDet; // remember signal level

} else { // if >24 then finish
outp(0 , TCCR1B); // stop timer 1
RC5BitCnt=0; // prepare for next time
if (!RC5PhaseErr && !RC5Avail) {
RC5Repeat=ControlBit==((RC5Data & 0x0800)==0x0800); // if new controlbit=old then RC5Repeat=1
ControlBit=((RC5Data & 0x0800)==0x0800); // new controlbit
RC5RxAddress=(unsigned char)((RC5Data & 0x07C0)>>6);
RC5RxCommand=(unsigned char)(RC5Data & 0x003F);
RC5Avail=TRUE; // RC5 code is vailable...
}
RC5PhaseErr=FALSE;
outp(0x40, GIMSK);
}
}

/* signal handler for external interrupt int0 */
SIGNAL(SIG_INTERRUPT0)
{
outp(0x00, GIMSK); // disable external int0
outp(0xF3, TCNT1H); // set TCNT1 // 3111 us
outp(0xD9, TCNT1L); // set TCNT1
outp(PRSC1_SELECT, TCCR1B); // start timer1
}

/* initialize RC5 decoder */
void RC5_init(void)
{
cbi(DDRD,PD2);
sbi(PORTD,PD2);

outp((1<<ISC01), MCUCR); // raise int0 on falling edge
outp(0x40, GIMSK); // enable external int0

outp(0x80, TIMSK); // enable timer1 Overflow interrupts
outp(0x00, TCCR1A); // disable PWM and stuff
outp(0x00, TCCR1B);
outp(0xF3, TCNT1H); // set TCNT1 // 3111 us
outp(0xD9, TCNT1L); // set TCNT1
}

/* main routine for testing */
int main(void)
{
sei(); // enable interrupts

RC5_init();
lcd_init();

lcd_control(1,0,0);
lcd_putstr("RC5 decoder");
lcd_goto(0x49);
lcd_putstr("PErr=");
while(1)
{
lcd_goto(0x0E);
printhex(heartbeat++); // heart beat :)

if (RC5Avail) { // display new RC5 data
lcd_goto(0x40);
printhex(RC5Repeat);
lcd_putch(' ');
printhex(RC5RxAddress);
lcd_putch(' ');
printhex(RC5RxCommand);
RC5Avail=FALSE; // ready to get new one
}
lcd_goto(0x4E);
printhex(RC5PhaseErr); // error check
delay(1000);
}
}