原创 24位高精度A/D转换器LTC2400读写应用

24bit高精度A/D转换器通信代码,MCU采用PIC16F877,读到的AD值传送到超级终端显示：

/************************************************************************************/
/*     程式名：LTC2400讀寫代碼                                                      */
/*                                                                                  */
/*     晶振：  20M                                           CPU型號： PIC16F877A   */
/*                                                                                  */
/*     作者：  Randy                                         日期：    2010-08-27   */
/*                                                                                  */
/************************************************************************************/
#include <pic.h>
#include <stdio.h>
__CONFIG(0X3732);
#define   ADC_SDO   RC4
#define   ADC_SCK   RC3
#define   ADC_CS    RC5
const unsigned char hz[]="輸入電壓是：";
const unsigned char de[]="V";
//unsigned int tmp[4]={0};
static bank1 unsigned long data,dianya;
static bank1 unsigned long voltage;
double x[5];
int t=0,zz;
static bank1 char m[9];
static bank1  unsigned long yushu[9];
//------------------------延時--------------------------------//
void delay_1ms(unsigned int x)
{
  unsigned a,b;
  for(a=5*x;a>0;a--)
   for(b=110;b>0;b--);
}
/*從SPI總線上讀入32bit*/
unsigned long read_ADC(void)
{
   char k;
   unsigned long n=0;
   ADC_CS = 1;
   ADC_SCK= 0;
   ADC_CS = 0;
   for(k=0; k<32; k++)
   {
     n << = 1;
     ADC_SCK = 1;
     n |= ADC_SDO;
  ADC_SCK = 0;
    }
 ADC_CS = 1;

if((n & 0x20000000) ==0)   //判讀輸入是否為負
t=1;
else     
t=0;
       n&=0x01fffffff; // maskout sign bit
       n>>=4;   // get 24-bit conversion result
     return n;
}

/* 5-point average */
double filter_ADC(void)
{
double L=0;
int i;
for(i=0;i<5;i++)    //5次平均
{
x=read_ADC();
if(t==1)            //輸入為負處理
{
   L+=0;
}