iic.c

用于iic的读写。上面有例子可以参考

//OK.7.14
//#include<AT89x52.h>
#include<reg52.h>
#include<intrins.h>

#define uchar unsigned char
#define uint unsigned int
#define Byte unsigned char
#define Word unsigned int

#define bool bit
#define true 1
#define false 0

#define SomeNOP(); _nop_();_nop_();_nop_();_nop_();_nop_();_nop_();

sbit SCL=P1^4;
sbit SDA=P1^5;

uchar SystemError;

RdFromROM(uchar Data[],uchar Address,uchar Num);
WrToROM(uchar Data[],uchar Address,uchar Num);
void I2CStart(void);
void I2CStop(void);
bool WaitAck(void);
//void SendAck(void);
void SendNotAck(void);
void I2CSendByte(Byte ch);
Byte I2CReceiveByte(void);
void mDelay(uchar j);

//uchar addr=1;

/*void main(void)
{
	uchar Wdat[6]={1,2,3,4,5,6};
	uchar Rdat[6];
	bit Bwflag=0;
	bit Brflag=0;
	Bwflag=WrToROM(Wdat,1,6);
    mDelay(10);
	Brflag=RdFromROM(Rdat,1,6);
	while(1);
}*/

WrToROM(uchar Data[],uchar Address,uchar Num)
{
	uchar ii;
	uchar *PData;
	bit j=0;
	bit i=0;
	PData=Data;
	for(ii=0;ii<Num;ii++)
	{
		I2CStart();
		I2CSendByte(0xa0);
		i=WaitAck();
		j=j|i;
		I2CSendByte(Address+ii);
		i=WaitAck();
		j=j|i;
		I2CSendByte(*(PData+ii));
		i=WaitAck();
		I2CStop();
		mDelay(20);
	}
	j=j|i;
	if(j) return true;
	else return false;
}

RdFromROM(uchar Data[],uchar Address,uchar Num)
{
	uchar ii;
	uchar *PData;
	bit j=0;
	bit i=0;
	PData=Data;
	for(ii=0;ii<Num;ii++)
	{
		I2CStart();
		I2CSendByte(0xa0);
		i=WaitAck();
		j=j|i;
		I2CSendByte(Address+ii);
		i=WaitAck();
		j=j|i;
		I2CStart();
		I2CSendByte(0xa1);
		i=WaitAck();
		j=j|i;		
		*(PData+ii)=I2CReceiveByte();
		SCL=0;
		SendNotAck();
		I2CStop();
	}
	if(j) return true;
	else return false;
}

void I2CStart(void)
{
	EA=0;
	SDA=1;SCL=1;SomeNOP();
	SDA=0;SomeNOP();
	//SCL=0;SomeNOP();
}

void I2CStop(void)
{
	//SCL=0;SDA=0;SomeNOP();
	//SCL=1;SomeNOP();SDA=1;
	SCL=1;SDA=0;SomeNOP();
	SDA=1;SomeNOP();
	EA=1;
}

bool WaitAck(void)
{
	uchar errtime=255;
	SDA=1;SomeNOP();
	SCL=1;SomeNOP();
	while(SDA){errtime--;if(!errtime){I2CStop();SystemError=0x11;return false;}}
	SCL=0;
	SDA=0;
	return true;
}

/*void SendAck(void)
{
	SDA=0;SomeNOP();
	SCL=1;SomeNOP();
	SCL=0;
}*/

void SendNotAck(void)
{
	SDA=1;SomeNOP();
	SCL=1;SomeNOP();
	SCL=0;
}

void I2CSendByte(Byte ch)
{
	uchar i=8;
	while(i--)
	{
		SCL=0;SomeNOP();
		SDA=(bit)(ch&0x80);ch<<=1;SomeNOP();
		SCL=1;SomeNOP();
	}
	SCL=0;
}

Byte I2CReceiveByte(void)
{
	uchar i=8;
	Byte ddata=0;
	SDA=1;
	while(i--)
	{
		ddata<<=1;
		SCL=0;SomeNOP();
		SCL=1;SomeNOP();
		ddata|=SDA;
	}
	SCL=0;
	return ddata;
}

void mDelay(uchar j)
{
uint i;
for(;j>0;j--)
	{
		for(i=0;i<125;i++)
		{;}
	}
}