51读写串行EEPROM芯片at2402程序（C）

/* Name:AT24C02存储器的读写程序,用到I2C总线,含相对独立的I2C总线读写函数 */
#include
#include
#include
#define DELAY_TIME 60 /*经实验，不要小于50！否则可能造成时序混乱*/

#define TRUE 1
#define FALSE 0

sbit SCL=P1^7;/*假设由P1.7和P1.6控制*/
sbit SDA=P1^6;

/********** 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(char b)reentrant
{
/*向I2C总线写一个字节*/
char i;
for(i=0;i<8;i++)
if((b< else
SEND_0();
}

char ReadI2CByte(void)reentrant
{
/*从I2C总线读一个字节*/
char b=0,i;
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(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