pinlv.rar_74595l_74595驱动程序_Ｃ５１

//******************************************************************** //频率计程序，计数9999Hz,大于显示"E " //p3.5计数输入 //laosong 2007.5.3.pm 在mcs51u实验板测试通过 #include <reg51.h> sbit dat=P1^0; //定义驱动74595的数据脚为p1.0 sbit clk=P1^1; //74595的时钟 sbit lat=P1^2; //栓锁 sbit gw=P1^3; //个位显示控制脚 sbit sw=P1^4; //十位 sbit bw=P3^3; //百位 sbit qw=P3^4; //千位 unsigned char msec; //闸门 union{ unsigned char c[2]; unsigned int i; }Freq; //------字表------------------------------ unsigned char code tab[]= { 0x3F,0x06,0x5B,0x4F, //"0","1","2","3" 0x66,0x6D,0x7D,0x07, //"4","5","6","7" 0x7F,0x6F,0x77,0x7c, //"8","9","A","B" 0x39,0x5e,0x79,0x71, //"C","D","E","F" 0x00, //" " } ; //----初始化------------------------------ void Init(void) { TMOD=0x51; //T1=16位外部计数器,T0=定时方式1 TH1=TL1=0; //计数器清0 TH0=0x3C;TL0=0xB0; //12.0000MHz@50mS ET0=1; } //------闸门中断-------------------------- void Timer0(void) interrupt 1 { TH0=0x3C;TL0=0xB0; //12.0000MHz@50mS msec++; //50mS +1 if (msec>=20) //1秒闸门 { TR1=0; //停止计数 EA=0; Freq.c[0]=TH1; Freq.c[1]=TL1; TH1=TL1=0; TH0=0x3C;TL0=0xB0; msec=0; //开始下次计数 EA=1; TR1=1; //开始计数 } } //------显示延时-------------------------- ds1ms() { unsigned char d; for(d=0;d<250;d++); //大约1ms@12M } //------送出循环------------------------- dsout(unsigned char j) { unsigned char i; for(i=0;i<8;i++) { dat=j&0x80; //高位在前 clk=1; clk=0; j<<=1; } lat=1; lat=0; //锁存 } //----74HC595显示程序-------------------- display(unsigned char sjqw,sjbw,sjsw,sjgw) { dsout(tab[sjgw]);gw=0;ds1ms();gw=1; //查表得到数据段码送显示 dsout(tab[sjsw]);sw=0;ds1ms();sw=1; dsout(tab[sjbw]);bw=0;ds1ms();bw=1; dsout(tab[sjqw]);qw=0;ds1ms();qw=1; } //--------------------------------------- main() { unsigned int t; unsigned char qwb,bwb,swb,gwb; //结果 Init(); EA=1; //允许闸门中断 TR0=1; //开计时闸门 TR1=1; //开始计数 while(1) { qwb=Freq.i/1000; //得到千位 t=Freq.i%1000; //取余 bwb=t/100; //得到百位 t=t%100; swb=t/10; //得到十位 gwb=t%10; //得到个位 if(qwb>9) //如果千位大于9 { qwb=0x0e;bwb=0x10;swb=0x10,gwb=0x10; //显示E，报错 } display(qwb,bwb,swb,gwb);//显示 } }