/* Name:AT24C02存儲器的讀寫程序,用到I2C總線,含相對獨立的I2C總線讀寫函數(shù) */
#include
#include
#include
#define DELAY_TIME 60 /*經(jīng)實驗，不要小于50！否則可能造成時序混亂*/

#define TRUE 1
#define FALSE 0

sbit SCL=P1^7;/*假設(shè)由P1.7和P1.6控制*/
sbit SDA=P1^6;

/********** Function Definition　函數(shù)定義 ************/

void DELAY(unsigned int t) /*延時函數(shù)*/
{
while(t!=0)
t--;
}

void I2C_Start(void)
{
/*啟動I2C總線的函數(shù)，當(dāng)SCL為高電平時使SDA產(chǎn)生一個負跳變*/
SDA=1;
SCL=1;
DELAY(DELAY_TIME);
SDA=0;
DELAY(DELAY_TIME);
SCL=0;
DELAY(DELAY_TIME);
}

void I2C_Stop(void)
{
/*終止I2C總線，當(dāng)SCL為高電平時使SDA產(chǎn)生一個正跳變*/
SDA=0;
SCL=1;
DELAY(DELAY_TIME);
SDA=1;
DELAY(DELAY_TIME);
SCL=0;
DELAY(DELAY_TIME);
}

void SEND_0(void) /* SEND ACK */
{
/*發(fā)送0，在SCL為高電平時使SDA信號為低*/
SDA=0;
SCL=1;
DELAY(DELAY_TIME);
SCL=0;
DELAY(DELAY_TIME);
}

void SEND_1(void)
{
/*發(fā)送1，在SCL為高電平時使SDA信號為高*/
SDA=1;
SCL=1;
DELAY(DELAY_TIME);
SCL=0;
DELAY(DELAY_TIME);
}

bit Check_AcknowLEDge(void)
{
/*發(fā)送完一個字節(jié)后檢驗設(shè)備的應(yīng)答信號*/
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(char b)reentrant
{
/*向I2C總線寫一個字節(jié)*/
char i;
for(i=0;i<8;i++)
if((b< else
SEND_0();
}

char ReadI2CByte(void)reentrant
{
/*從I2C總線讀一個字節(jié)*/
char b=0,i;
for(i=0;i<8;i++)
{
SDA=1; /*釋放總線*/
SCL=1; /*接受數(shù)據(jù)*/
DELAY(10);
F0=SDA;
DELAY(10);
SCL=0;
if(F0==1)
{
b=b<<1;
b=b|0x01;
}
else
b=b<<1;
}
return b;
}

/**********以下為讀寫24c02的函數(shù)**********/
void Write_One_Byte(char addr,char thEDAta)
{
bit acktemp=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();

}

void Write_A_Page(char *buffer,char addr)
{
bit acktemp=1;
bit wrtmp;
int i;
/*write a page to at24c02*/
I2C_Start();
WriteI2CByte(0xa0);
acktemp=Check_Acknowledge();
WriteI2CByte(addr);/*address*/
acktemp=Check_Acknowledge();
for(i=0;i<7;i++)
{
WriteI2CByte(buffer[i]);
if(!Check_Acknowledge())
{
I2C_Stop();

}
}

I2C_Stop();

}

char Read_One_Byte(char addr)
{ bit acktemp=1;
char mydata;
/*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();

return mydat