temp_e2prom.c

一个单片机实现DA转换程序,程序实现了一个温度控制的数摸转换,并添加了去抖动处理!!

#include "iom16.h"
#include "ioavr.h"
#include "inavr.h"
#include "avr_macros.h"

#include "userdef.h"
#include "userfun.h"
#include "userram.h"
#include "disdata.h"
//#include "usertype.h"


/******* 延时  *********/
void I2cWait(void)
{
   __no_operation();
   __no_operation();
   __no_operation();
   __no_operation();
   __no_operation();
   __no_operation();
   __no_operation();
   __no_operation();
   __no_operation();
   __no_operation();
   __no_operation();
   __no_operation();
   __no_operation();
   __no_operation();
   __no_operation();
   __no_operation();
   __no_operation();
   __no_operation();
   __no_operation();
   __no_operation();
}


/*************************  I2C通信启动  ***************************/
void I2cStart(void)
{
   SDA_HIGH;                 //数据线输出高电平
   SCL_HIGH;                 //时钟线输出高电平
   I2cWait();                //延时
   SDA_LOW;                  //数据线拉低
   I2cWait();                //延时
   SCL_LOW;                  //时钟线拉低
}


/*******  I2C通信停止  *********/
void I2cStop(void)           //I2c停止信号
{
   SDA_LOW;                  //数据线拉低
   I2cWait();                //延时
   I2cWait();
   SCL_HIGH;                 //时钟线拉高
   I2cWait();                //延时
   SDA_HIGH;                 //数据线变高
}


/******  发送确认信号  ********/
void SendAck (unsigned char ack)
{
     if ( ack==0 )   {   SDA_LOW;  }    //发送 0
        else      {   SDA_HIGH; }       //发送 1
     SCL_HIGH;                          //时钟信号变高
     I2cWait();                         //延时
     SCL_LOW;                           //时钟信号变低
     I2cWait();
     SDA_HIGH;                          //数据线变高,为下次传送作准备
}


/******* 发送一个字节数据  *********/
void I2cSentByte(unsigned char bytedata)
{
   unsigned char i,ack;

   for(i=0;i<8;i++)                     //循环 8 次
   {
      if(bytedata & 0x80)
        {
        SDA_HIGH;
        }
      else
        {
        SDA_LOW;
        }
      bytedata <<= 1;                   //数据左移
      I2cWait();                        //延时
      SCL_HIGH;                         //时钟信号变高,模拟正脉冲
      I2cWait();                        //延时
      SCL_LOW;                          //时钟信号变低,为下一次输入做准备
      I2cWait();                        //延时
   }
   SDA_HIGH;                            //数据线变高,为接受响应信号作准备
   I2cWait();                           //延时
   SCL_HIGH;                            //时钟信号变高
   I2cWait();                           //延时
   ack= !(PINB BIT3) ? 0:1 ;            //取得确认信号
   SCL_LOW;                             //时钟信号变低
   I2cWait();                           //延时

   write_error=ack;
}


/******* 接收一个字节数据  *********/
unsigned char I2cReceiveByte(void)
{
   unsigned char i,bytedata=0;
   SDA_HIGH;
   for(i=0;i<8;i++)                      //循环 8 次
   {
      SCL_HIGH;                          //时钟信号变高
      I2cWait();                         //延时

      bytedata <<= 1;                    //数据左移
      if( PINB BIT3 )   bytedata|=0x01;  //取得输入数据

      SCL_LOW;                           //时钟信号变低
      I2cWait();                         //延时
   }
   return bytedata;                      //返回接收数据
}


/******* 从LM77中读出温度数据  *********/
unsigned int  ReadLM77(void)
{
     unsigned int temp1;
     unsigned int  i;
	
     I2cStart();
     I2cSentByte(LM77Address);
     I2cSentByte(0x00);                 //SELECT TEMPERATURE REGISTER

     I2cStart();
     I2cSentByte(LM77Address+1);
     i=I2cReceiveByte();

     SendAck(0);
     temp1=I2cReceiveByte();
     SendAck(1);
     I2cStop();

     i=i<<8;
     i=i+temp1;
     i=i>>3;

     for(temp1=0;temp1<16000;temp1++);
     return i;
}