连接多个相同地址I2C设备的C51程序

本人初学C,曾为这个问题大伤脑筋^_^,就是一个单片机系统有两个以上的相同地址的I2C设备,无法用两个同一对SDA/SCL引脚

#include "stc89c51.h"

#include "iic.h"

sbit scl0=P3^5;

sbit sda0 = P3^4;

sbit scl1= P3^3;

sbit sda1 = P3^2;

//这里只写了两个I2C设备,如果需要可以再加上 sbit scl2=xx; sbit sda2=xx; 实际上多个设备的scl脚可以共用

unsignedchariic_delay_time = 8;

voidscl(device,value);

voidsda(device,value);

bit sdasense(chardevice);

// delay

voidiic_delay(unsignedcharm)

{

unsignedcharn;

for(n=0;n

}

//

voidscl(device,value)

{

if(device==0) //设备1

scl1=value;

if(device==1) //设备2

scl2=value;

}

voidsda(device,value)

{

if(device==0) //设备1

sda1=value;

if(device==1) //设备2

sda2=value;

}

bit sdasense(chardevice)

{

switch(device)

{

case1:returnsda1;

break;

case2:returnsda2;

break;

}

}

//启动I2C总线的函数，当scl为高电平时使sda产生一个负跳变

voidiic_start(device)

{

sda(device,1);

scl(device,1);

iic_delay(iic_delay_time);

sda(device,0);

iic_delay(iic_delay_time);

scl(device,0);

iic_delay(iic_delay_time/2);

}

//终止I2C总线，当scl为高电平时使sda产生一个正跳变

voidiic_stop(device)

{

scl(device,0);

sda(device,0);

scl(device,1);

iic_delay(iic_delay_time);

sda(device,1);

iic_delay(iic_delay_time);

}

//发送应答信号

voidiic_ack(device) {

sda(device,0);

scl(device,1);

scl(device,0);

sda(device,1);

}

//发送无应答信号

voidiic_noack(device)

{

sda(device,1);

scl(device,1);

scl(device,0);

}

//检测应答信号

bit iic_testack(device)

{

bit errorbit; //真确应答,返回0

sda(device,1);

iic_delay(iic_delay_time);

scl(device,1);

iic_delay(iic_delay_time);

errorbit=sdasense(device);

scl(device,0);

iic_delay(iic_delay_time);

return(errorbit);

}

//发送一个字节

voidiic_write8bit(device,unsignedcharinput)

{

unsignedchartemp;

for(temp=0;temp<8;temp++)

{

if((input<

sda(device,1);

else

sda(device,0);

scl(device,1);

iic_delay(iic_delay_time);

scl(device,0);

}

}

//读一个字节

unsignedchariic_read8bit(device)

{

unsignedchartemp,rbyte=0;

for(temp=0;temp<8;temp++)

{

scl(device,1);

iic_delay(iic_delay_time);

if(sdasense(device))

rbyte=(rbyte<<1)+1;

else

rbyte=rbyte<<1;

scl(device,0);

}

return(rbyte);

}