在51上用P1口模拟I2C

下面是用普通C51实现的I2C基本电平模拟函数和通用函数。

/*电平模拟函数和基本读写函数
void IIC_Start(void);
void IIC_Stop(void);
void SEND_0(void);
void SEND_1(void);
bit Check_Acknowledge(void);
void Write_Byte(uchar b)reentrant;
bit Write_N_Bytes(uchar *buffer,uchar n)reentrant;
bit Read_N_Bytes(uchar SlaveAdr,uchar n,uchar *buffer);
uchar Read_Byte(void)reentrant;
*/

#include
#include
#include
#include"aiic_51.h"

sbit SCL=P1^6;
sbit SDA=P1^7;

void DELAY(uint t)
{
while(t!=0)
t--;
}

void IIC_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 IIC_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)
{
//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 Write_Byte(uchar b)reentrant
{
//向IIC总线写一个字节
uchar i;
for(i=0;i<8;i++)
if((b< SEND_1();
else
SEND_0();
}

bit Write_N_Bytes(uchar *buffer,uchar n)reentrant
{
//向I2C总线写n个字节
uchar i;
IIC_Start();

for(i=0;i {
Write_Byte(buffer);
if(!Check_Acknowledge())
{
IIC_Stop();
return(i==n);
}
}

IIC_Stop();
return TRUE;
}

uchar Read_Byte(void)reentrant
{
//从I2C总线读一个字节
uchar 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;
}

bit Read_N_Bytes(uchar SlaveAdr,uchar n,uchar *buffer)
{
//从I2C总线读n个字节
uchar i;
IIC_Start();
Write_Byte(SlaveAdr); //向总线发送接收器地址
if(!Check_Acknowledge()) //等待接收器应答信号
return FALSE;
for(i=0;i {
buffer=Read_Byte();
if(i!=n)
SEND_0(); //发送应答
else
SEND_1(); //发送非应答
}
IIC_Stop();
return TRUE;
}



使用上述代码，你可以在51上用P1口模拟I2C