电压表实验（AD转换）

 1 /*电压表 精确到小数点后面三位*/
 2 /*连线：电位器接IN0，AD_CS接CS0,CS1接KEY/LED_CS*/
 3 #include<reg52.h>
 4 typedef unsigned char uchar;
 5 xdata uchar LED_CS _at_ 0x9000;
 6 xdata uchar LED_OUTSEG _at_ 0x9004;
 7 xdata uchar LED_OUTBIT _at_ 0x9002;
 8 
 9 xdata uchar AD_CS _at_ 0x8000;
10 xdata uchar AD_MODE _at_ 0x8003;
11 
12 code unsigned char LEDMAP[] = {  // 八段管显示码
13   0x3f, 0x06, 0x5b, 0x4f, 0x66, 0x6d, 0x7d, 0x07,
14   0x7f, 0x6f, 0x77, 0x7c, 0x39, 0x5e, 0x79, 0x71
15 };
16 code unsigned char LEDWED[] = {0x20,0x10,0x08,0x04,0x02,0x01};
17 int num[6];
18 void delay(int ms)
19 {
20  int i,j;
21  for(i=0;i<ms;i++)
22     for(j=0;j<14;j++)
23          ;
24 }
25 void adf()
26 {
27  AD_CS = 0;
28  delay(10);
29 }
30 void main()
31 {
32  int led_c=0;
33  unsigned char temp;
34  AD_MODE = 0x82;
35  AD_CS = 0;
36  while(1)
37  {
38   adf();
39   delay(10);
40   num[0] = AD_CS*5/256;
41   num[1] = AD_CS*5%256*10/256;
42   num[2] = AD_CS*5%256*10%256*10/256;
43   num[3] = AD_CS*5%256*10%256*10%256*10/256;
44   temp = LEDMAP[num[led_c]];
45   if(led_c == 0)
46            temp = temp|0x80;
47   LED_OUTBIT = LEDWED[led_c];
48   LED_OUTSEG = temp;
49   led_c = (led_c+1)%4;
50   delay(10);
51  }
52 }