引入该头文件，直接调用uchar readbyte (uint add) void writebyteseq(uint add,uchar *ptr,uint writelen) 函数即可
注意FM_DATA引脚必须接上拉电阻，否则不能正常读取数据，数据时和时钟线接51单片机准双向口。
#include<reg52.h>
#include<intrins.h>
#include "stc12c5a16s2.h"
#define IIC_READ 0XA1 //定义读指令
#define IIC_WRITE 0XA0 //定义写指令
#define uchar unsigned char //定义一下方便使用
#define uint unsigned int
#define NOP _nop_()
/***************************************************************/
uchar idata buff[32]; //save the byte read out form iic device in test operation
uchar idata readbuff[32];//测试数组，暂存写入读出数据
//uchar writebuff[32];
//===============================
sbit SDA = P4^5; //THE SDA BIT IS PORT 4 BIT 2
sbit SCL = P4^4; //THE SCL BIT IS PORT 1 BIT 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 confirm if ACK has happened
bit NO_ACK; //no ack flag
/***************************************************************/
//FUNCTION:ROUTES TO PROVIDE A START SIGNAL
void start(void)
{
SCL=0;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;SCL=0;
}
//=====================================
//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
unsigned char inbyte(void)
{ //从IIC器件中读出数据
unsigned char get_value,i;
get_value=0;
SCL=0;
for(i=0;i<8;i++)
{
SDA=1;
SCL = 1;
get_value <<= 1;//首先接收到的为最高位
if(SDA==1)get_value += 1;
SCL = 0;
}
return get_value;
}
//=======================================================
//FUNCTION:THE IIC DEVICE SHIFT IN A BYTE FROM THE MASTER
void outbyte(unsigned char outdata) {//将数据写入IIC器件
unsigned int i;
SCL=0;
for(i=0;i<8;i++)
{
if(outdata & (0x80>>i)) // 1000 0000
{
SDA=1;
SCL=1; //高电平数据有效
SCL=0;
}
else
{
SDA=0;
SCL=1; //高电平数据有效
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; //A0
if(add>>8){temp|=0x02;} //add = 0x01,temp= A0 else temp = A2 10000000
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; // A0;
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<writelen;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<readlen-1;i++)
{
*(ptr+i)=inbyte();
ack();
}
*(ptr+readlen-1)=inbyte();
nack();
stop();
}
//=======================================================
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