i2c.c

I2C卡读写驱动

#include "I2c.h"
#include"string.h"

//#ifdef  _USE_I2C 

void Init_I2c()
{
	SDA_1;
	SCL_1;
	SCL_OUT; //CLK为输出状态
	SDA_OUT;
}

//----------------------------------------------------------------------------------
//I2C 软件模拟程序
//----------------------------------------------------------------------------------
void i2c_start(void)
{
	SDA_OUT;
	SDA_1;                     //将数据置1
	NOP2;
	SCL_1;                     //时钟置1
	NOP2
	SDA_0;                     //启动
	NOP2;
	SCL_0;                     //start 
	NOP2;
}

void i2c_stop(void)
{ 
	SDA_OUT;
	SDA_0;
	NOP2;
	SCL_1;
	NOP2;
	SDA_1;
	NOP2;
}

void i2c_bytewrite(uchar writedata)
{
	uchar i;

	for(i=0; i<8; i++)
	{
		if (writedata & BIT7)
			SDA_1;
		else
			SDA_0;
		writedata <<= 1;
		SCL_1;
		NOP4;
		SCL_0;
		NOP2;
	}
}

uchar i2c_byteread(void)
{
	uchar i,tempdata=0;

	SDA_IN;                                      //置为输入

	for (i=0; i<8; i++)
	{
		SCL_1;
		_NOP();
		tempdata <<= 1;
		if (SDA_VAL)
			tempdata |= 1;
		SCL_0;
		NOP4;
	}
	return tempdata;
}

void Acknowledge(void)
{

	SCL_0;
	NOP2;
	SDA_OUT;  
	SDA_0;  
	SCL_1;  
	NOP2;  
	SCL_0;
}

void ReceiveAck(void)
{
	uchar i = 0;
	SCL_1; 
	SDA_IN;                                         //送回应脉冲
	NOP2;
	while ((SDA_VAL) && (i < 20))i++;
	SDA_OUT;
	SCL_0;
	NOP2;
}


uchar I2c_Read(uint i2caddr)
{
	uchar tempdata;

	i2c_start();
	i2c_bytewrite(DEVADDR_WR);                      //写地址
	ReceiveAck();
	i2c_bytewrite(i2caddr>>8);                      //写高地址
	ReceiveAck();
	i2c_bytewrite(i2caddr);                         //写低地址
	ReceiveAck();
	i2c_start();
	i2c_bytewrite(DEVADDR_RD);                      //读地址
	ReceiveAck();
	tempdata = i2c_byteread(); 
	i2c_stop();
	Delay(20);
	return tempdata;
}

//从I2C读取字符串，数据保存在 p 指向的缓冲区
//返回读取的字节数  
#define MAX_I2C_STRING  32
uchar I2cReadString(uint addr,uchar*p)
{
	uchar *pDst = p;
	uchar i;
	for(i=0;i<MAX_I2C_STRING-1;i++)   
	{
		*pDst = I2c_Read(addr);
		if(*pDst++ == 0) break;
	}
	*pDst =0;//体面结束
	return i;
}

void I2c_Write(uint i2caddr,uchar i2cdata)
{ 
	i2c_start();
	i2c_bytewrite(DEVADDR_WR);                      //写地址
	ReceiveAck();
	i2c_bytewrite(i2caddr>>8);                      //写高地址
	ReceiveAck();
	i2c_bytewrite(i2caddr);                         //写低地址
	ReceiveAck();
	i2c_bytewrite(i2cdata);
	ReceiveAck();
	i2c_stop();
	Delay(4800);
}

//高位在前
uint I2c_ReadInt(uint i2caddr)
{
	uint tempdata;

	i2c_start();
	i2c_bytewrite(DEVADDR_WR);                      //写地址
	ReceiveAck();
	i2c_bytewrite(i2caddr>>8);                      //写高地址
	ReceiveAck();
	i2c_bytewrite(i2caddr);                         //写低地址
	ReceiveAck();
	i2c_start();
	i2c_bytewrite(DEVADDR_RD);                      //写读取地址
	ReceiveAck();
	tempdata = i2c_byteread()&0xFF; 
	tempdata <<=8;
	Acknowledge();
	tempdata += i2c_byteread()&0xFF; 
	i2c_stop();
	return tempdata;
}
//高位在前
ulong I2c_ReadLong(uint i2caddr)
{
    ulong tempdata;
    i2c_start();
    i2c_bytewrite(DEVADDR_WR);                      //写地址
    ReceiveAck();
    i2c_bytewrite(i2caddr>>8);                      //写高地址
    ReceiveAck();
    i2c_bytewrite(i2caddr);                         //写低地址
    ReceiveAck();
    i2c_start();
    i2c_bytewrite(DEVADDR_RD);                      //写读取地址
    ReceiveAck();
    tempdata = i2c_byteread()&0xFF; 
    tempdata <<=8;
    Acknowledge();
    tempdata += i2c_byteread()&0xFF; 
    tempdata <<=8;
    Acknowledge();
    tempdata += i2c_byteread()&0xFF; 
    tempdata <<=8;
    Acknowledge();
    tempdata += i2c_byteread()&0xFF; 
    i2c_stop();
    return tempdata;
}
//高位在前
void I2c_WriteInt(uint i2caddr,uint i2cdata)
{
	i2c_start();
	i2c_bytewrite(DEVADDR_WR);                      //写地址
	ReceiveAck();
	i2c_bytewrite(i2caddr>>8);                      //写高地址
	ReceiveAck();
	i2c_bytewrite(i2caddr);                         //写低地址
	ReceiveAck();
	i2c_bytewrite(i2cdata>>8);
	ReceiveAck();
	i2c_bytewrite(i2cdata);
	ReceiveAck();
	i2c_stop();
	Delay(4800);
}
void I2CWritestring(ulong addr,const char*p)
{
	uchar i;
	i=strlen(p);
	for( ;  i ; i -- )
		I2c_Write(addr++, *(p++));
}


//高位在前
void I2c_WriteLong(uint i2caddr, ulong i2cdata)
{   
    i2c_start();
    i2c_bytewrite(DEVADDR_WR);                      //写地址
    ReceiveAck();
    i2c_bytewrite(i2caddr>>8);                      //写高地址
    ReceiveAck();
    i2c_bytewrite(i2caddr);                         //写低地址
    ReceiveAck();
    i2c_bytewrite(i2cdata>>24);
    ReceiveAck();
    i2c_bytewrite(i2cdata>>16);
    ReceiveAck();
    i2c_bytewrite(i2cdata>>8);
    ReceiveAck();
    i2c_bytewrite(i2cdata);
    ReceiveAck();
    i2c_stop();
    Delay(4800);
}

//页写入
void I2c_WriteData(uint i2caddr, uchar len , uchar *pdata)
{
	uchar idx,idx2,cnt=(len+31)>>5;

	//每次可以写入32字节
	for (idx=0;idx<cnt;idx++)
	{
		i2c_start();
		i2c_bytewrite(DEVADDR_WR);                      //写地址
		ReceiveAck();
		i2c_bytewrite((i2caddr+(idx<<5))>>8);           //写高地址
		ReceiveAck();
		i2c_bytewrite(i2caddr+(idx<<5));                         //写低地址
		ReceiveAck();
		for (idx2=idx<<5;idx2<(idx<<5)+32 && idx2<len;idx2++)
		{
			i2c_bytewrite(*(pdata+idx2));
			ReceiveAck();        
		}
		i2c_stop();
		Delay(4800);
	}
}



//#endif