EEPROM at24c256读写

/******************************************

*

* Description: EEPROM Read/Write.

* Author：LY

* Date: 2013-07-24 

*

******************************************/

#include <c8051f340.h>

#include "at24c128.h"

//Write:0xA0,Read:0xA1 读写间须延时

#define  EEPROM_ADDR    0xA0 

#define  DELAY_TIME       1  

extern void delay(uint uiCnt);

unsigned char i2c_eeprom_byte_write(unsigned int uiAddr, unsigned char ucData)

{

  unsigned char ucTmp;

  unsigned int    uiTmp;

  unsigned char i;

  

   SDA = 1;

   SCL = 1;

   delay(DELAY_TIME);

   //start bit

   SDA = 0;

   delay(DELAY_TIME);

   

  //device addr

  ucTmp = 0xA0;

  for(i = 0; i<8;i++)

  {

      SCL = 0;

 delay(DELAY_TIME);

      if(ucTmp & 0x80)

      {

      SDA = 1;

      }
 else

   {

      SDA = 0;

   }
 delay(DELAY_TIME);
 ucTmp <<=  1;
 SCL = 1;

      delay(DELAY_TIME);

  }

  //ack read

  SCL = 0;

  SDA = 1;

   delay(DELAY_TIME);

   

   if(SDA == 0)  //ack ok

   {

      SCL = 1;  

      delay(DELAY_TIME);  

   }

   else //ack error

   {

      SCL = 1;  

      delay(DELAY_TIME);  
 

     //stop bit send 

     SCL = 0;

     SDA = 0;

      delay(DELAY_TIME);  

      SCL = 1;  

      delay(DELAY_TIME);  

      SDA = 1; 

      return 1;

   }

   //high address

   uiTmp = uiAddr;

   uiTmp >>= 8;

   ucTmp = uiTmp;

  for(i = 0; i<8;i++)

  {

      SCL = 0;
 delay(DELAY_TIME);

      if(ucTmp & 0x80)

      {

      SDA = 1;

      }
 else

   {

      SDA = 0;

   }

 delay(DELAY_TIME);

 ucTmp <<=  1;

 SCL = 1;

      delay(DELAY_TIME);

  }

  //ack read

  SCL = 0;

  SDA = 1;

   delay(DELAY_TIME);

   

   if(SDA == 0)  //ack ok

   {

      SCL = 1;  

      delay(DELAY_TIME);  

   }

   else //ack error

   {

      SCL = 1;  

      delay(DELAY_TIME);  
 

     //stop bit send 

     SCL = 0;

     SDA = 0;

      delay(DELAY_TIME);  

      SCL = 1;  

      delay(DELAY_TIME);  

      SDA = 1; 

      return 1;

   }

  

   //low address

   ucTmp = uiAddr;

  for(i = 0; i<8;i++)

  {

      SCL = 0;
 delay(DELAY_TIME);

      if(ucTmp & 0x80)

      {

      SDA = 1;

      }
 else

   {

      SDA = 0;

   }

 delay(DELAY_TIME);

 ucTmp <<=  1;

 SCL = 1;

      delay(DELAY_TIME);

  }

  //ack read

  SCL = 0;

  SDA = 1;

   delay(DELAY_TIME);

   

   if(SDA == 0)  //ack ok

   {

      SCL = 1;  

      delay(DELAY_TIME);  

   }

   else //ack error

   {

      SCL = 1;  

      delay(DELAY_TIME);  
 

     //stop bit send 

     SCL = 0;

     SDA = 0;

      delay(DELAY_TIME);  

      SCL = 1;  

      delay(DELAY_TIME);  

      SDA = 1; 

      return 1;

   }

    //data send

   ucTmp = ucData;

  for(i = 0; i<8;i++)

  {

      SCL = 0;
 delay(DELAY_TIME);

      if(ucTmp & 0x80)

      {

      SDA = 1;

      }
 else

   {

      SDA = 0;

   }

 delay(DELAY_TIME);

 ucTmp <<=  1;

 SCL = 1;

      delay(DELAY_TIME);

  }

  //ack read

  SCL = 0;

  SDA = 1;

   delay(DELAY_TIME);

   

   if(SDA == 0)  //ack ok

   {

      SCL = 1;  

      delay(DELAY_TIME);  

   }

   else //ack error

   {

      SCL = 1;  

      delay(DELAY_TIME);  
 

     //stop bit send 

     SCL = 0;

     SDA = 0;

      delay(DELAY_TIME);  

      SCL = 1;  

      delay(DELAY_TIME);  

      SDA = 1; 

      return 1;

   }

     //stop bit send 

     SCL = 0;

     SDA = 0;

      delay(DELAY_TIME);  

      SCL = 1;  

      delay(DELAY_TIME);  

      SDA = 1; 

     return 0;

}

unsigned char i2c_eeprom_byte_read(unsigned int uiAddr)

{

  unsigned char ucTmp;

  unsigned int  uiTmp;

  unsigned char i;

  unsigned char ucData;

   F0=0;

   SDA = 1;

   SCL = 1;

   delay(DELAY_TIME);

   //start bit

   SDA = 0;

   delay(DELAY_TIME);

   

  //device addr

  ucTmp = 0xA0;

  for(i = 0; i<8;i++)

  {

      SCL = 0;
 delay(DELAY_TIME);

      if(ucTmp & 0x80)

      {

      SDA = 1;

      }
 else

   {

      SDA = 0;

   }

 delay(DELAY_TIME);

 ucTmp <<=  1;

 SCL = 1;

      delay(DELAY_TIME);

  }

  //ack read

  SCL = 0;

  SDA = 1;

   delay(100);

   

   if(SDA == 0)  //ack ok

   {

      SCL = 1;  

      delay(DELAY_TIME);  

   }

   else //ack error

   {

    F0=1;

   /*   SCL = 1;   //111

      delay(DELAY_TIME);  
 

     //stop bit send 

     SCL = 0;

     SDA = 0;

      delay(DELAY_TIME);  

      SCL = 1;  

      delay(DELAY_TIME);  

      SDA = 1; 

      return 1; //*/

   }

   //high address

   uiTmp = uiAddr;

   uiTmp >>= 8;

   ucTmp = uiTmp;

  for(i = 0; i<8;i++)

  {

      SCL = 0;
 delay(DELAY_TIME);

      if(ucTmp & 0x80)

      {

      SDA = 1;

      }
 else

   {

      SDA = 0;

   }

 delay(DELAY_TIME);

 ucTmp <<=  1;

 SCL = 1;

      delay(DELAY_TIME);

  }

  //ack read

  SCL = 0;

  SDA = 1;

   delay(DELAY_TIME);

   

   if(SDA == 0)  //ack ok

   {

      SCL = 1;  

      delay(DELAY_TIME);  

   }

   else //ack error

   {  F0=1;

  /*    SCL = 1;    //111

      delay(DELAY_TIME);  
 

     //stop bit send 

     SCL = 0;

     SDA = 0;

      delay(DELAY_TIME);  

      SCL = 1;  

      delay(DELAY_TIME);  

      SDA = 1; 

      return 1; //*/

   }

  

   //low address

   ucTmp = uiAddr;

  for(i = 0; i<8;i++)

  {

      SCL = 0;
 delay(DELAY_TIME);

      if(ucTmp & 0x80)

      {

      SDA = 1;

      }
 else

   {

      SDA = 0;

   }

 delay(DELAY_TIME);

 ucTmp <<=  1;

 SCL = 1;

      delay(DELAY_TIME);

  }

  //ack read

  SCL = 0;

  SDA = 1;

   delay(DELAY_TIME);

   

   if(SDA == 0)  //ack ok

   {

      SCL = 1;  

      delay(DELAY_TIME);  

   }

   else //ack error

   {   F0=1;

/*      SCL = 1;    //111

      delay(DELAY_TIME);  
 

     //stop bit send 

     SCL = 0;

     SDA = 0;

      delay(DELAY_TIME);  

      SCL = 1;  

      delay(DELAY_TIME);  

      SDA = 1; 

      return 1; //*/

   }

   //start bit

   SCL = 0;

   SDA = 1;

   delay(DELAY_TIME);  

   SCL = 1;

   delay(DELAY_TIME);  

   SDA = 0;

   delay(DELAY_TIME);  

   //device address, read

  ucTmp = 0xA1;

  for(i = 0; i<8;i++)

  {

      SCL = 0;
 delay(DELAY_TIME);

      if(ucTmp & 0x80)

      {

      SDA = 1;

      }
 else

   {

      SDA = 0;

   }

 delay(DELAY_TIME);

 ucTmp <<=  1;

 SCL = 1;

      delay(DELAY_TIME);

  }

  //ack read

  SCL = 0;

  SDA = 1;

   delay(DELAY_TIME);

   

   if(SDA == 0)  //ack ok

   {

      SCL = 1;  

      delay(DELAY_TIME);  

   }

   else //ack error

   {   F0=1;

 /*     SCL = 1;      //111

      delay(DELAY_TIME);  
 

     //stop bit send 

     SCL = 0;

     SDA = 0;

      delay(DELAY_TIME);  

      SCL = 1;  

      delay(DELAY_TIME);  

      SDA = 1; 

      return 1; //*/

   }

   //read data

  ucData = 0;

  for(i = 0; i<8;i++)

  {

      SCL = 0;

      delay(DELAY_TIME);

      if(SDA)

      {

      ucData |= 0x01;

      }
else

  {

      ucData &= (~0x01);

  }

       if(i<7)

      {

            ucData <<= 1;

       }

SCL = 1;
delay(DELAY_TIME);

  }

   

  //ack read, no ack----

  SCL = 0;

  SDA = 1;

   delay(DELAY_TIME);

   if(SDA == 1)  //ack ok

   {

      SCL = 1;  

      delay(DELAY_TIME);  

   }

   else //ack error

   {

      SCL = 1;  

      delay(DELAY_TIME);  
 

   }

   

     //stop bit send 

     SCL = 0;

     SDA = 0;

      delay(DELAY_TIME);  

      SCL = 1;  

      delay(DELAY_TIME);  

      SDA = 1;
 
 return   ucData;

}