ads1110.c

ADS1100/ADS1110 C51接口程序源代码

//ADS1110
//AD转换程序
#include <reg52.h>
#include <intrins.h>

sbit SDA=P3^3;          /*I2C的SDA线定义*/
sbit SCL=P3^1;      	/*I2C的SCL线定义*/

//发起始位
void start(void)
{
	SDA=1;
	SCL=1;
	SDA=0;
	SCL=0;
}
//发停止位
void stop(void)
{
   	SDA=0;
   	SCL=1;
   	SDA=1;
   	SCL=0;
 }
//发非应答位
void mnack(void)
{
   	SDA=1;
   	SCL=1;
   	SDA=0;
   	SCL=0;
}
//发应答位
void mack(void)
{
	SDA=0;
  	SCL=1;
  	SCL=0;
  	SDA=1;
}
//应答位测试
bit cack(void)
{
  	bit samp;
  	samp=0;
  	SDA=1;
  	SCL=1;
  	samp=SDA;
  	SCL=0;
  	return (samp);
}
//发一字节数据
void wrbyte(unsigned char w_data)
{
  	unsigned char i,buf;
  	for (i=0;i<8;i++)
    {
      	buf=0x80&w_data;
      	w_data=_crol_(w_data,1);
      	if (buf==0x80)                          /*发送位为1*/
        {
          	SDA=1;
        }
		SCL=1;
        SCL=0;
        SDA=0;
    }
 }
//收一字节数据
unsigned char rdbyte(void)
{
  	unsigned char buf1,i;
  	bit temp;
  	buf1=0;
  	for (i=0;i<8;i++)
    {
      	SDA=1;
      	SCL=1;
      	temp=SDA;
      	if (temp==1)                             /*接收位是1*/
        {
         	buf1=0x80|buf1;
         	buf1=_crol_(buf1,1);
        }
      	else                                     /*接收位是0*/
        {
         	buf1=0x7f&buf1;
         	buf1=_crol_(buf1,1);
        }
     	SCL=0;
  	}
   	return (buf1);
}

//读取AD转换值
unsigned int ReadADC(void)
{
  	unsigned char temp1,temp2,i;
  	unsigned int adcnumber;

	i=20;
  	start();                 /*发起始位*/
  	do{

  		wrbyte(0x91);//ED0的读地址
		i--;
  	} while (cack()==1 && i>0);

  	temp1=rdbyte();
  	mack(); //发应答位
  	temp2=rdbyte();
  	mnack();//发非应答位
  	stop();
  	adcnumber=temp1*256+temp2;
	return adcnumber;
}
//设置ADS1100
void SetADC(unsigned char writedata)
{
	unsigned char temp1,temp2,i;
  	unsigned int adcnumber;

	i=20;
  	start();                 /*发起始位*/
  	do{

  		wrbyte(0x90);
		i--;
  	} while (cack()==1 && i>0);
	i=20;
	do{

  		wrbyte(writedata);		
  	} while (cack()==1 && i>0);

	stop();
}