#include <reg51.h>
#define c(x) (x*110592/120000) 

sbit Ir_Pin=P3^7;
sbit beep=P3^6;

unsigned char code Led_Tab[]={0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,
      0x80,0x90,0x88,0x83,0xc6,0xa1,0x86,0x8e,0xbf};                        //共陽極數碼顯示碼0-F.
unsigned char code Led_Sel[]={0xfe,0xfd,0xfb,0xf7,0xef,0xdf,0xbf,0x7f};

unsigned char Led_Buf[7]; //顯示緩沖區
char Led_Index;                   //位選         
unsigned char Ir_Buf[4]; //用于保存解碼結果


void delay_50ms(unsigned int t)
{
	unsigned int j;   
		for(;t>0;t--) 
			for(j=6245;j>0;j--) 
				{;}
}

//==============================================================
//數碼管掃描
timer0() interrupt 1 using 1
{
	TL0=65536-1000;
	TH0=(65536-1000)/256; //定時器0設定約1000us中斷一次，用于數碼管掃描
	P0=0xff;
	P2=Led_Sel[Led_Index];                            //位選
	P0=Led_Tab[Led_Buf[Led_Index]];                    //段選
	if(++Led_Index>7) 
		Led_Index=0;                    //八個掃描完了,到第一個數碼管

}
//==============================================================
unsigned int Ir_Get_Low()
{
	TL1=0;
	TH1=0;
	TR1=1;
	while(!Ir_Pin && (TH1&0x80)==0);                
	TR1=0;           
	return TH1*256+TL1;
}
//=============================================================
unsigned int Ir_Get_High()
{
	TL1=0;
	TH1=0;
	TR1=1;
	while(Ir_Pin && (TH1&0x80)==0);
	TR1=0;
	return TH1*256+TL1;
}
//==============================================================
main()
{
	unsigned int temp;
	char i,j;
	Led_Index=0;
	TMOD=0x11;
	TL0=65536-1000;
	TH0=(65536-1000)/256; //定時器0設定約1000us中斷一次，用于數碼管掃描
	EA=1;
	ET0=1;
	TR0=1;

	do{
		restart:
	while(Ir_Pin);

	temp=Ir_Get_Low();
	if(temp<c(8500) || temp>c(9500)) 
		continue;//引導脈沖低電平9000
	temp=Ir_Get_High();

	if(temp<c(4000) || temp>c(5000)) 
		continue;//引導脈沖高電平4500

	for(i=0;i<4;i++){ //4個字節
		for(j=0;j<8;j++) //每個字節8位
		{
			temp=Ir_Get_Low();
			if(temp<c(200) || temp>c(800)) goto restart;
				temp=Ir_Get_High();

			if(temp<c(200) || temp>c(2000)) goto restart;
				Ir_Buf[i]>>=1;

			if(temp>c(1120)) Ir_Buf[i]|=0x80;
		}
	}
		Led_Buf[0]=(Ir_Buf[0]/16)&0xf;//顯示結果
		Led_Buf[1]=Ir_Buf[0]&0xf;	   //顯示結果
		Led_Buf[2]=(Ir_Buf[1]/16)&0xf; //顯示結果
		Led_Buf[3]=Ir_Buf[1]&0xf;		 //顯示結果
		Led_Buf[4]=(Ir_Buf[2]/16)&0xf; //顯示結果
		Led_Buf[5]=Ir_Buf[2]&0xf;		 //顯示結果
		Led_Buf[6]=(Ir_Buf[3]/16)&0xf; //顯示結果
		Led_Buf[7]=Ir_Buf[3]&0xf;		 //顯示結果
		beep=0;
		delay_50ms(2);
		beep=1;
	}while(1);
}