//-----------------------------I2C.H----------------------//
#ifndef __I2C_H__
#define __I2C_H__
#include <string.h>
#include <at89x51.h>
#include <intrins.h>
#define uchar unsigned char
#define uint unsigned int
#define DELAY_TIME 60 /*经实验，12M晶振不要小于50！否则可能造成时序混乱*/
#define TRUE 1
#define FALSE 0
sbit SCL=P1^1;/*假设由P1.7和P1.6控制*/
sbit SDA=P1^2;
sbit wp=P1^0;
/********** Function Definition 函数定义 ************/
void DELAY(unsigned int t) /*延时函数*/
{
while(t!=0)
t--;
}
void I2C_Start(void)
{
/*启动I2C总线的函数，当SCL为高电平时使SDA产生一个负跳变*/
SDA=1;
SCL=1;
DELAY(DELAY_TIME);
SDA=0;
DELAY(DELAY_TIME);
SCL=0;
DELAY(DELAY_TIME);
}
void I2C_Stop(void)
{
/*终止I2C总线，当SCL为高电平时使SDA产生一个正跳变*/
SDA=0;
SCL=1;
DELAY(DELAY_TIME);
SDA=1;
DELAY(DELAY_TIME);
SCL=0;
DELAY(DELAY_TIME);
}
void SEND_0(void) /* SEND ACK */
{
/*发送0，在SCL为高电平时使SDA信号为低*/
SDA=0;
SCL=1;
DELAY(DELAY_TIME);
SCL=0;
DELAY(DELAY_TIME);
}
void SEND_1(void)
{
/*发送1，在SCL为高电平时使SDA信号为高*/
SDA=1;
SCL=1;
DELAY(DELAY_TIME);
SCL=0;
DELAY(DELAY_TIME);
}
bit Check_Acknowledge(void)
{
/*发送完一个字节后检验设备的应答信号*/
SDA=1;
SCL=1;
DELAY(DELAY_TIME/2);
F0=SDA;
DELAY(DELAY_TIME/2);
SCL=0;
DELAY(DELAY_TIME);
if(F0==1)
return FALSE;
return TRUE;
}
void WriteI2CByte(uchar b)reentrant
{
/*向I2C总线写一个字节*/
uchar i;
wp=1; //modified=======================
for(i=0;i<8;i++)
if((b<<i)&0x80)
SEND_1();
else
SEND_0();
wp=0; //===============================
}
uchar ReadI2CByte(void)reentrant
{
/*从I2C总线读一个字节*/
uchar b=0,i;
wp=0;
for(i=0;i<8;i++)
{
SDA=1; /*释放总线*/
SCL=1; /*接受数据*/
DELAY(10);
F0=SDA;
DELAY(10);
SCL=0;
if(F0==1)
{
b=b<<1;
b=b|0x01;
}
else
b=b<<1;
}
return b;
}
/**********以下为读写24c02的函数**********/
void Write_One_Byte(uchar addr,uchar thedata)
{
bit acktemp=1;
wp=1;
/*write a byte to mem*/
I2C_Start();
WriteI2CByte(0xa0);
acktemp=Check_Acknowledge();
WriteI2CByte(addr);/*address*/
acktemp=Check_Acknowledge();
WriteI2CByte(thedata);/*thedata*/
acktemp=Check_Acknowledge();
I2C_Stop();
wp=0;
}
void Write_A_Page(uchar *buffer,uchar m,uchar addr)
{
bit acktemp=1;
uint i;
// bit wrtmp;
wp=1;
/*write a page to at24c02*/
I2C_Start();
WriteI2CByte(0xa0);
acktemp=Check_Acknowledge();
WriteI2CByte(addr);/*address*/
acktemp=Check_Acknowledge();
for(i=0;i<m;i++)
{
WriteI2CByte(buffer[i]);
// if(!Check_Acknowledge())
// {
// I2C_Stop();
// }
acktemp=Check_Acknowledge();
}
I2C_Stop();
wp=0;
}
uchar Read_One_Byte(uchar addr)
{ bit acktemp=1;
uchar mydata;
wp=0;
/*read a byte from mem*/
I2C_Start();
WriteI2CByte(0xa0);
acktemp=Check_Acknowledge();
WriteI2CByte(addr);/*address*/
acktemp=Check_Acknowledge();
I2C_Start();
WriteI2CByte(0xa1);
acktemp=Check_Acknowledge();
mydata=ReadI2CByte();
// acktemp=Check_Acknowledge();
SEND_1(); /*发送非应答*/
return mydata;
I2C_Stop();
}
void Read_N_Bytes(uchar *buffer,uchar n,uchar addr)
{
bit acktemp=1;
int i=0;
wp=0;
/*read 8 bytes from mem*/
I2C_Start();
WriteI2CByte(0xa0);
acktemp=Check_Acknowledge();
WriteI2CByte(addr);/*address*/
acktemp=Check_Acknowledge();
I2C_Start();
WriteI2CByte(0xa1);
acktemp=Check_Acknowledge();
for(i=0;i<n;i++)
{
buffer[i]=ReadI2CByte();
if(i!=n-1)
SEND_0(); /*发送应答*/
else
SEND_1(); /*发送非应答*/
}
I2C_Stop();
}
#endif
