c8051f020实现存储器eeprom at24c02的数据读写.txt

实现存储器EEPROM AT24C02的数据读写*作,同时了解软件实现I2C总线读写

C8051F020实现存储器EEPROM AT24C02的数据读写*作,同时了解软件实现I2C总线读写/***************************************************************
功能:实现存储器EEPROM AT24C02的数据读写*作,同时了解软件实现I2C总线读写
作者:ZDP
时间:2005-11-30
版本:V1.0
***************************************************************/
#include <c8051f020.h>
#include <INTRINS.H>
#define  WriteDeviceAddress 0xa0 //写驱动地址指令
#define  ReadDeviceAddress 0xa1  //读驱动地址指令

sbit SCL = P0^7;
sbit SDA = P0^6;

/*-------------------------------------------------------------
功能：发起始信号
------------------------------------------------------------*/
void Start_Cond()
{
 SCL = 0;
    _nop_();
 SDA = 1;
    _nop_();
 SCL = 1;
    _nop_();
 SDA = 0;
 _nop_();
}

/*-------------------------------------------------------------
功能：发停止信号
------------------------------------------------------------*/
void Stop_Cond()
{
 SCL = 0;
 _nop_();
 SDA = 0;
 _nop_();
 SCL = 1;
 _nop_();
 SDA = 1;
 _nop_();
}

/*-------------------------------------------------------------
功能：发确认信号
------------------------------------------------------------*/
void Ack()
{
 SCL = 0;
 _nop_();
 SDA = 0;
 SCL = 1;
 _nop_();
 SCL = 0;
 _nop_();
 SDA = 1;
}

/*-------------------------------------------------------------
功能：发无确认信号
------------------------------------------------------------*/
void NoAck()
{
 SCL = 0;
 _nop_();
 SDA = 1;
 _nop_();
 SCL = 1;
 _nop_();
 SCL = 0;
 _nop_();
}

/*-------------------------------------------------------------
功能：写一个字节数据
------------------------------------------------------------*/
bit Write8Bit(unsigned char input)
{
 unsigned char i;
 for (i=0;i<8;i++)
 { 
  SCL = 0;
  input <<= 1;
  SDA = CY;
  SCL = 1;
 }
 SCL = 0;
    _nop_();
 SDA = 1;
 SCL = 1;
    _nop_();
 CY = SDA;
 return(CY) ;
}

/*-------------------------------------------------------------
功能：读一个字节数据
------------------------------------------------------------*/
unsigned char Read8Bit()
 {
 unsigned char temp,rbyte=0;
 for (temp = 8;temp != 0;temp--)
 {
  SCL = 0;
  _nop_();
  rbyte = (rbyte << 1) | SDA;
  SCL = 1;
        _nop_();
 }
 return rbyte;
}

/*-------------------------------------------------------------
功能：从EEPROM中给定一个地址连续读NLEN个字节数据存放在以指针
nContent开头的往下内容。
------------------------------------------------------------*/
bit Read_Flash ( unsigned char *nContent, unsigned char nAddr, unsigned char nLen )
{
 unsigned char Addr;
 Addr = nAddr;
 Start_Cond();      //写开始信号
 Write8Bit(WriteDeviceAddress);  //写驱动地址
 Write8Bit(Addr);     //写从EEPROM中读的开始地址
        Start_Cond();     //写开始信号
        Write8Bit(ReadDeviceAddress); //写读数据指令
 while(--nLen)
 {
  *nContent=Read8Bit();   //读出内容
  nContent++;      //指针加1
  Ack();       //发确认信号
 }
 *nContent=Read8Bit();    //读一字节
  NoAck();       //没有确认信号
 Stop_Cond();      //发停止信号
 return(0);       //返回
}

/*-------------------------------------------------------------
功能：初始化EEPROM子程序内容为FF
------------------------------------------------------------*/
bit Init_Flash ( unsigned int nPage ) //8字节为一页面全写0xff
{
 unsigned char nLen;
 unsigned char Addr;
 nLen=8;
    Addr=8 *nPage;
 Start_Cond();
    Write8Bit(WriteDeviceAddress);
 Write8Bit(Addr);
 for(;nLen!=0;nLen--)
    {
  if(Write8Bit(0xff)) break;
 }
 Stop_Cond();
    return(CY);
}

/*-------------------------------------------------------------
功能：从EEPROM中给定一个地址连续写NLEN个字节数据存放在以指针
nContent开头的往下内容。
------------------------------------------------------------*/
bit Write_Flash ( unsigned char *nContent, unsigned char nAddr,unsigned char nLen)
{
 unsigned char i,temp;
 unsigned char Addr;
 Addr = nAddr;
 Start_Cond();     //写开始信号
  Write8Bit(WriteDeviceAddress); //写驱动地址
 Write8Bit(Addr);    //写从EEPROM中写的开始地址 
 for(i = 0;i < nLen;i++)
 { temp = *nContent;
  Write8Bit(temp);     //CY
  nContent++;
        Addr++;
  if(Addr%8==0)      //每页8字节 换页
  { Stop_Cond();
            for(temp=0;temp!=255;temp++)
    {_nop_();}
   Start_Cond();
   Write8Bit(WriteDeviceAddress);
   Write8Bit(Addr);
  }
 }
 Stop_Cond();     //发停止信号
 return(CY);
}

/*-------------------------------------------------------------
主程序
功能：实现存储器EEPROM AT24C02的数据读写*作
------------------------------------------------------------*/

void main()
{unsigned char dat[16],i;
 WDTCN     = 0xDE;
 WDTCN     = 0xAD;   //关闭WDT

 P0MDOUT   = 0x80;
 XBR2      = 0x40;   //配置I/O端口

 Read_Flash(dat,0,16);  //读出AT24C02中从地址0开始依次往后16个字节放入dat数组中  
 Init_Flash(0);    //将AT24C02的第0页初始化为FF
 Init_Flash(1);    //将AT24C02的第0页初始化为FF
 Read_Flash(dat,0,16);  //读出AT24C02中从地址0开始依次往后16个字节放入dat数组中

 for(i = 0;i < 16;i++ )
 {
  dat[i] = i;       //对数组dat初始化为0---F
 }     
 Write_Flash(dat,0,16);  //将dat数组中的数据写入AT24C02中地址从0开始
 _nop_();
 Read_Flash(dat,0,16);  //读出AT24C02中从地址0开始依次往后16个字节放入dat数组中
 while(1);