利用XPT2046制作一个电位器AD转换装置

  1 #include <reg52.h>
  2 #include<intrins.h>
  3 
  4 #define uint unsigned int 
  5 #define uchar unsigned char
  6 #define GPIO_DUAN P0
  7 
  8 uchar table[]={
  9     0x3f, 0x06, 0x5b, 0x4f,
 10     0x66, 0x6d, 0x7d, 0x07,
 11     0x7f, 0x6f, 0x77, 0x7c,
 12     0x39, 0x5e, 0x79, 0x71
 13 };
 14 
 15 uchar DisplayData[5];
 16 sbit HCA = P2^2;//HCA,HCB,HCC是利用了74HC138译码器来进行位选，我们动态位选了4位
 17 sbit HCB = P2^3;
 18 sbit HCC = P2^4;
 19 sbit CLK  = P1^0;
 20 sbit CS   = P1^1;
 21 sbit DIN  = P1^2;
 22 sbit DOUT = P1^3;
 23 
 24 void DisplayDS();
 25 void delayms(uint xms);
 26 uint Read_AD_Data(uchar moshi);
 27 void SPI_Write(uchar moshi);
 28 uint GetValue();
 29 
 30 void main()
 31 {
 32     uint temp, cnt = 50;
 33     while(1){
 34         if(cnt == 50){//每50下读取转换值，避免数字跳动太快
 35             temp = Read_AD_Data(0x94);
 36             cnt = 0;
 37         }
 38         cnt++;
 39         
 40         DisplayData[0] = table[temp%10000/1000];
 41         DisplayData[1] = table[temp%1000/100];
 42         DisplayData[2] = table[temp%100/10];
 43         DisplayData[3] = table[temp%10/1];
 44         
 45         DisplayDS();
 46     }
 47 }
 48 
 49 void DisplayDS()
 50 {//动态扫描函数
 51     uint i;
 52     for(i = 0; i < 4; i++){
 53         GPIO_DUAN = 0x00;
 54         switch(i)
 55         {
 56             case 0 : HCC = 0; HCB = 0; HCA = 0; break;
 57             case 1 : HCC = 0; HCB = 0; HCA = 1; break;
 58             case 2 : HCC = 0; HCB = 1; HCA = 0; break;
 59             case 3 : HCC = 0; HCB = 1; HCA = 1; break;
 60         }    
 61         GPIO_DUAN = DisplayData[i];
 62         delayms(1);
 63     }
 64 }
 65 
 66 void delayms(uint xms)
 67 {
 68     uint i, j;
 69     for(i = 0; i < xms; i++)
 70         for(j = 0; j < 110; j++);
 71 }
 72 
 73 uint Read_AD_Data(uchar moshi)
 74 {//读取最终的数字量函数
 75     uint i, ans;
 76     SPI_Write(moshi);    
 77     for(i = 0; i < 5; i++);
 78     
 79     CLK = 1;
 80     _nop_();
 81     _nop_();
 82     CLK = 0;
 83     _nop_();
 84     _nop_();
 85     
 86     ans = GetValue();
 87     CS = 1;
 88     return ans;
 89 }
 90 
 91 void SPI_Write(uchar moshi)
 92 {//写模式函数
 93     uint i;
 94     CS = 0;
 95     for(i = 0; i < 8; i++){    
 96         CLK = 0;
 97         DIN = moshi>>7;
 98         CLK = 1;
 99         moshi <<= 1;
100     }
101     CLK = 0;
102 }
103 
104 uint GetValue()
105 {//读取DOUT管脚，得到最终数字量函数
106     uint i, ans = 0;
107     for(i = 0; i < 12; i++){
108         CLK = 0;
109         ans <<= 1;
110         ans |= DOUT;
111         CLK = 1;
112     }
113     CLK = 0;
114     return ans;
115 }