电压表实验（AD转换）

/*电压表 精确到小数点后面三位*/ 

 /*连线：电位器接IN0，AD_CS接CS0,CS1接KEY/LED_CS*/ 

 #include<reg52.h> 

 typedef unsigned char uchar; 

 xdata uchar LED_CS _at_ 0x9000; 

 xdata uchar LED_OUTSEG _at_ 0x9004; 

 xdata uchar LED_OUTBIT _at_ 0x9002; 



 xdata uchar AD_CS _at_ 0x8000; 

 xdata uchar AD_MODE _at_ 0x8003; 



 code unsigned char LEDMAP[] = {  // 八段管显示码 

   0x3f, 0x06, 0x5b, 0x4f, 0x66, 0x6d, 0x7d, 0x07, 

   0x7f, 0x6f, 0x77, 0x7c, 0x39, 0x5e, 0x79, 0x71 

 }; 

 code unsigned char LEDWED[] = {0x20,0x10,0x08,0x04,0x02,0x01}; 

 int num[6]; 

 void delay(int ms) 

 { 

  int i,j; 

  for(i=0;i<ms;i++) 

     for(j=0;j<14;j++) 

          ; 

 } 

 void adf() 

 { 

  AD_CS = 0; 

  delay(10); 

 } 

 void main() 

 { 

  int led_c=0; 

  unsigned char temp; 

  AD_MODE = 0x82; 

  AD_CS = 0; 

  while(1) 

  { 

   adf(); 

   delay(10); 

   num[0] = AD_CS*5/256; 

   num[1] = AD_CS*5%256*10/256; 

   num[2] = AD_CS*5%256*10%256*10/256; 

   num[3] = AD_CS*5%256*10%256*10%256*10/256; 

   temp = LEDMAP[num[led_c]]; 

   if(led_c == 0) 

            temp = temp|0x80; 

   LED_OUTBIT = LEDWED[led_c]; 

   LED_OUTSEG = temp; 

   led_c = (led_c+1)%4; 

   delay(10); 

  } 

 }