ex4-1.c

< 嵌入式C语言程序设计>>一书的源代码

 #include<reg52.h>
 #include<absacc.h>
 #define uchar unsigned char
 #define AD0809 XBYTE[0xcfa0]
 sbit start=p3^3;
 sbit led=p1^1;
 void main(void)
 {
 uchar a=155,b;
 while (1)
  { AD0809=b;
  while(start==0){;}
  b=Ad0809;
  if(b>=a)
  led=1;
  else 
  led=0;
  }}