iic.c

IIC READ AND WRITE iic器件的读取 连续读取和页读取

#include   <reg52.h>
#include	"delay.h"
#include	"iic.h"

/*启动IIC设备*/
void start(void)
{
	DelayMs(5);
	SDA = 1 ;
	Delay(5);
	SCL = 1 ;
	Delay(5);
	SDA = 0 ;
	Delay(5);
	SCL = 0 ;
	Delay(5);
}


/*停止IIC设备*/
void stop(void)
{
	Delay(5);
  	SCL = 0 ;
	Delay(5);
	SDA = 0 ;
	Delay(5);
	SCL = 1 ;
	Delay(5);
	SDA = 1 ;
	Delay(5);
	DelayMs(15);
}

/*检测ack*/
bit testack(void)
{
	bit AckFlag;
	Delay(5);
	SDA = 1;
	Delay(5);
	SCL = 1;
	Delay(5);
	AckFlag = SDA;
	SCL = 0;
	Delay(5);
	return(AckFlag);
}

/*发送应答信号*/
void sendack(void)
{
 	Delay(5);
	SDA = 0;
	Delay(5);
	SCL = 1;
	Delay(5);
	SCL = 0; 
	Delay(5);
	SDA = 1;
	Delay(5);
}
/*发送非应答信号*/
void sendNack(void)
{
	Delay(5);
	SDA = 1 ;
	Delay(5);
	SCL = 1 ;
	Delay(5);
	SCL = 0 ;
	Delay(5);
}

/*写1个字节的数据*/
void write8bit(unsigned char T_Data)
{
	unsigned char i ;	
	for(i = 8; i != 0; i--)
	{
		SDA = (bit)(T_Data & 0x80);
		Delay(5);
		SCL = 1 ;
		Delay(5);
		SCL = 0 ;
		Delay(5);
		T_Data = T_Data << 1 ;
		Delay(5);
	}
}

/*读1个字节的数据*/
unsigned char read8bit(void)
{
	unsigned char i = 0 ;
	unsigned char R_Data = 0x00 ;
	
	for(i = 8; i != 0; i--)
	{
		SDA = 1;
		Delay(5);
		SCL = 0 ;
		Delay(5);
		Delay(5);
		SCL = 1 ;
		R_Data = R_Data << 1 ;
		R_Data = R_Data |((unsigned char)(SDA)) ;
		SCL = 0 ;
		Delay(5);
	}
	return(R_Data);
}

/*写1个字节的数据到指定的地址*/
void write_I2C(unsigned char RomAddress,unsigned char T_Data)
{
	start() ;
	write8bit(WrDevAddr) ;
	testack() ;
	write8bit(RomAddress) ;
	testack() ;
	write8bit(T_Data) ;
	testack() ;
	stop() ;
}


/*读1个字节的数据*/
unsigned char read_I2C(unsigned char RomAddress)
{
	unsigned char R_Data = 0x00 ;
	start() ;
	write8bit(WrDevAddr) ;
	testack() ;
	write8bit(RomAddress) ;
	testack() ;
	start() ;
	write8bit(RdDevAddr) ;
	testack() ;
	R_Data = read8bit() ;
	sendNack() ;
	stop() ;
	return(R_Data) ;
}

/*指定的地址写页-8字节数据*/
void WriteOnePage (unsigned char addr,unsigned char *thedata)    //写入一页8个字节到指定开始地址，可以自动翻页
{
    unsigned char i;                        //计数器
    start();                        			//开始总线
    write8bit(WrDevAddr);               //发送控制数据
    testack();               						//检查应答信息
    write8bit(addr);                    //写入地址
    testack();
    for(i=0;i<8;i++)                		//循环写入第一页的数据
    {        
        write8bit(*thedata);            //写入数据
        testack();
        thedata++;                    //数据指针加1
    }
    stop();                        		//停止总线
}

/*指定的地址写N(N<=8)字节数据*/
void WriteNByte (unsigned char addr,unsigned char *thedata,unsigned char n)    //写入N个字到指定开始地址
{
    unsigned char i;                        //计数器
    start();                        				//开始总线
    write8bit(WrDevAddr);                   //发送控制数据
    testack();               								//检查应答信息
    write8bit(addr);                    		//写入地址
    testack();
    for(i=0;i<n;i++)                				//循环写入第一页的数据
    {        
        write8bit(*thedata);            		//写入数据
        testack();
        thedata++;                    		//数据指针加1
    }
    stop();                        				//停止总线
}

/*指定地址，页写n个数据*/
void WritePages(unsigned char addr,unsigned char *thedata,unsigned char n)
{
	unsigned char page=n/8;
	unsigned char leave=n%8;
	unsigned char i;
	for(i=0;i<page;i++)
	{
		WriteOnePage((addr+8*i),thedata);
		thedata=thedata+8;
	}
	WriteNByte((addr+8*page),thedata,leave);
}

/*指定地址，读取8字节，页读*/
void ReadoOnePage(unsigned char addr,unsigned char *thedata)            //连续读取8个字节 页
{
	unsigned char i;
    start();                       
    write8bit(WrDevAddr);                   
    testack();
    write8bit(addr);
    testack();
    start();
    write8bit(RdDevAddr) ;
    testack();
    for(i=0;i<7;i++)                		//8字节
    {        
        *thedata=read8bit();            //读取数据
       	sendack();                    	//发送应答，表示继续读取
        thedata++;                    	//数据指针加1
    }
    *thedata=read8bit();                //读取最后一个数据
    sendNack();                        //发送非应答，结束读取
    stop();                        		//停止总线
}

 /*连续读取N个字节*/
void ReadNByte (unsigned char addr,unsigned char *thedata,unsigned char n)           
{	
    unsigned char i;
    start();                       
    write8bit(WrDevAddr);                   
    testack();
    write8bit(addr);
    testack();
    start();
    write8bit(RdDevAddr) ;
    testack();
    for(i=0;i<n-1;i++)                		//n字节
    {   
        *thedata=read8bit();            //读取数据
       	sendack();                    	//发送应答，表示继续读取
        thedata++;                    	//数据指针加1
    }
    *thedata=read8bit();                //读取最后一个数据
    sendNack();                        //发送非应答，结束读取
    stop();   	
}