AT89s51-ADC0804实验

/*****************************************ADC0804，AT89S51连接：数码管:P0数据，段选P2^7,位选P2^6.ADC0804:数据输出P1WR=P3^6RD=P3^7INTR悬空CS接GND 现象：拧动滑动变阻器 数码管示数在0--255之间*****************************************/#include reg51.h>   #include intrins.h>sbit duanxuan=P2^7;sbit weixuan=P2^6; sbit AD_WR=P3^6;  //定义ADC0804的WR端口sbit AD_RD=P3^7;  //定义ADC0804的RD端口unsigned char shu[8];unsigned char code duanma[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f,0x77,0x7c,0x39,0x5e,0x79,0x71};unsigned char code weima[]={0xfe,0xfd,0xfb,0xf7,0xef,0xdf,0xbf,0x7f};/****************************************延时函数****************************************/void delayms(unsigned int xms)    {unsigned char i,j;for(i=xms;i>0;i--) for(j=120;j>0;j--);}/****************************************显示函数****************************************/void display(){unsigned char i;for(i=0;i3;i++){P0=0;duanxuan=1;duanxuan=0;P0=weima[i];weixuan=1;weixuan=0;P0=shu[i];duanxuan=1;duanxuan=0;delayms(4);} }/****************************************MAIN****************************************/void main() {unsigned char adval;unsigned int a ;while(1){AD_WR=1;_nop_();AD_WR=0;//启动AD转换_nop_();AD_WR=1;for(a=10;a>0;a--)  //启动转换后要多留点时间用来转换{ display();}P1=0xff;  //读取P1口之前先给其写全1 AD_RD=1;  _nop_(); AD_RD=0;//AD读使能_nop_();adval=P1;  //AD数据读取赋给advalAD_RD=1;shu[0]=duanma[adval/100];shu[1]=duanma[adval%100/10];shu[2]=duanma[adval%10];display();for(a=100;a>0;a--)display();}}