IIC总线的都可以用，注意要是用在AT24C系列的EEPROM 是要添加一定的延时程序~

比较简洁的程序：

#define uchar unsigned char

#define uint unsigned int

#define IIC_READ 0XA1 //定义读指令

#define IIC_WRITE 0XA0 //定义写指令

#define NOP _nop_()

//===============================

sbit SDA=P2^7; //THE SDA BIT IS PORT 2 BIT 7//

sbit SCL=P2^6; //THE SCL BIT IS PORT 2 BIT 6

sbit WP=P2^5;

sbit test=P1^0;

//===============================

//define a bit_operation byte to use in shift operation

//use this mode can achieve high operation speed uchar bdata bbyte;

//定义位操作用数组，采用此方法可提高位操作速度

sbit a0=bbyte^0;

sbit a1=bbyte^1;

sbit a2=bbyte^2;

sbit a3=bbyte^3;

sbit a4=bbyte^4;

sbit a5=bbyte^5;

sbit a6=bbyte^6;

sbit a7=bbyte^7;

//========================================

bit IFACK; //record the SDA state to confirn if ACK has happened

bit NO_ACK; //no ack flagbit BUS_FAULT; //bus fault flag

//========================================

//FUNCTION:ROUTES TO PROVIDE A START SIGNAL

void start(void)

{

SDA=1;

SCL=1;

SDA=0;

SCL=0;

}

//=======================================

//FUNCTION:ROUTES TO PROVIDE A STOP SIGNAL

void stop(void)

{

SCL=0;

SDA=0;

SCL=1;

SDA=1;

}

//=====================================

//FUNCTION:ROUTES TO PROVIDE ACK SINGAL

void ack(void)

{

SCL=0;

SDA=0;

SCL=1;

SCL=0;

}

//=====================================

//FUNCTION:ROUTES TO RELEASE THE SDA TO RECEIVE A ACK SIGNAL

// OR TO PROVIDE A NO_ACK SIGNAL

//type=1等待应答信号

//type=0 产生无应答信号

void nack(uchar type)

{

SCL=0;SDA=1;SCL=1;IFACK=SDA; SCL=0;

if(type)

{

if(IFACK)//如果无应答信号，则置标志位NO_ACK,程序中止

{ NO_ACK=1;//用户可以加入自己的异常处理程序//

while(1);

}else NO_ACK=0;

}

}

//=======================================================

//FUNCTION:THE IIC DEVICE SHIFT OUT A BYTE TO THE MASTER

uchar inbyte(void)

{

//从IIC器件中读出数据SDA=1;

SCL=1;a7=SDA;SCL=0;

SCL=1;a6=SDA;SCL=0;

SCL=1;a5=SDA;SCL=0;

SCL=1;a4=SDA;SCL=0;

SCL=1;a3=SDA;SCL=0;

SCL=1;a2=SDA;SCL=0;

SCL=1;a1=SDA;SCL=0;

SCL=1;a0=SDA;SCL=0;

return(bbyte);

}

//=======================================================

//FUNCTION:THE IIC DEVICE SHIFT IN A BYTE FROM THE MASTER

void outbyte (uchar outdata)

{ //将数据写放IIC器件bbyte=outdata;

SDA=a7;SCL=1;SCL=0;

SDA=a6;SCL=1;SCL=0;

SDA=a5;SCL=1;SCL=0;

SDA=a4;SCL=1;SCL=0;

SDA=a3;SCL=1;SCL=0;

SDA=a2;SCL=1;SCL=0;

SDA=a1;SCL=1;SCL=0;

SDA=a0;SCL=1;SCL=0;

}

//======================================================

//FUNCTION:BYTE WRITE. 'add' THE WRITE ADDRESS, 'wbyte' THE DATA WANT TO WRITE

void writebyte(uint add,uchar wbyte)//add为写入地址，wbyte为写入数据

{

uchar temp;

temp=IIC_WRITE;

if(add>>8)

{

temp|=0x02;

}

start(); //开始信号

outbyte(temp); //写命令nack(1); //等待应答

outbyte((uchar)add); //写地址

nack(1); //等待应答

outbyte(wbyte); //写数据

nack(1); //等待应答

stop(); //停止信号

}

//=====================================================

//FUNCTION:RANDOM READ.'add' IS THE ADDRESS WANT TO READ

uchar readbyte (uint add)//add为读地址

{

uchar temp,tempr;

temp=IIC_WRITE;

tempr=IIC_READ;

if(add>>8)

{

temp|=0x02;

tempr|=0x02;

}

start(); //开始信号

outbyte(temp); //写命令

nack(1); //等待应答

outbyte((uchar)add); //写地址

nack(1); //等待应答

start(); //开始信号

outbyte(tempr); //读命令

nack(1); //等待应答

temp=inbyte(); //读数据

nack(0); //无应答

stop(); //停止信号

return(temp);}

//=================================================

//连写函数

//add为读起始地址，ptr数据保存指针,writelen为写入数据长度

void writebyteseq(uint add,uchar *ptr,uint writelen)

{

uchar temp;

uint i;

temp=IIC_WRITE;

if(add>>8)

{

temp|=0x02;}

start();

outbyte(temp);

nack(1);

outbyte((uchar)add);

nack(1);

for(i=0;i

{

outbyte(*(ptr+i));nack(1);

}

stop();

}

//=================================================

//连读函数

//add为读起始地址，ptr数据保存指针,writelen为读出数据长度

void readbyteseq(uint add,uchar *ptr,uint readlen)

{

uchar temp,tempr;

uint i;

temp=IIC_WRITE;

tempr=IIC_READ;

if(add>>8)

{

temp|=0x02;tempr|=0x02;

}

start();

outbyte(temp);

nack(1);

outbyte((uchar)add);

nack(1);

start();

outbyte(tempr);

nack(1);

for(i=0;i

{

*(ptr+i)=inbyte();

ack();

}

*(ptr+readlen-1)=inbyte();

nack(0);

stop();

}