/********************************************************/
//項(xiàng)目名稱：轉(zhuǎn)速表
//硬件結(jié)構(gòu)：89c51+4位共陽(yáng)數(shù)碼管
/********************************************************/
#include <at89x51.h>
unsigned int led[4],count_x=0;
unsigned long int v=0;
unsigned char count_n=0,i,a,b,c;
unsigned char code table1[]={0xC0,0xF9,0xA4,0xB0,0x99,
0x92,0x82,0xF8,0x80,0x90};//共陽(yáng)極數(shù)碼管的編碼 

void display(unsigned int velocity)//顯示函數(shù)
{
    led[0]=velocity/0x3E8;
    led[1]=(velocity-led[0]*1000)/0x64;
    led[2]=(velocity-led[0]*1000-led[1]*100)/0xA;
    led[3]=velocity%0xA;
    for(i=0,c=0x01;i<=4,c<=0x08;c*=2,i++)
    {    
        EA=0;//關(guān)閉中斷
        P0=table1[led[i]];
        P2=c;
        for(a=6;a>0;a--)
            for(b=248;b>0;b--);
    }

    EA = 1; //允許CPU中斷
    ET0 = 1; //定時(shí)器0中斷打開(kāi)
    EX0=1;//打開(kāi)外部中斷0
    IT0=1;//脈沖方式觸發(fā)*/    
}
void main(void)
{
    EA = 1; //允許CPU中斷
    ET0 = 1; //定時(shí)器0中斷打開(kāi)
    EX0=1;//打開(kāi)外部中斷0
    IT0=1;//脈沖方式觸發(fā)
    TMOD = 0x1; //設(shè)定時(shí)器0為模式1，16位模式
    TH0=0xFF;
    TL0=0xCD; //設(shè)定時(shí)值為50us
    TR0 = 1; //開(kāi)始定時(shí)
    while(1);
}

void outinterrupt0(void) interrupt 0//外部中斷服務(wù)程序
{
    count_n++;
    if(count_n==2)
    {
        v=300000/count_x;
        count_x=0;
        count_n=0;            
        display(v);        
    }
}

void KeyAndDis_Time0(void) interrupt 1//定時(shí)中斷服務(wù)程序
{
    TH0=0xFF;
    TL0=0xDA; //設(shè)定時(shí)值
    if(count_n==1)
    {
        count_x++;
    }
}