51单片机IIC多机通信实验及proteus仿真

#include<reg51.h> #include<intrins.h> typedef unsigned int u16; typedef unsigned char u8; sbit SDA=P1^1; sbit SCL=P1^0; void At24CO2Write(u8 add,u8 dat,u8 addr); u8 At24CO2Read(u8 add,u8 addr); u8 numer[10]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f}; u8 display[4]; sbit A1=P2^2; sbit B1=P2^3; sbit C1=P2^4; #define SHUMA P0 sbit K1=P3^0;//保存 sbit K2=P3^1;//读取 sbit K3=P3^2; sbit K4=P3^3; sbit K5=P3^4;//num++ sbit K6=P3^5;//清零 sbit led=P2^0; u8 num; void delay(u16 i) { while(i--); } void delay10us(void) { unsigned char a,b; for(b=1;b>0;b--) for(a=2;a>0;a--); } void shumaguan(u8 word[]) { u8 i; for(i=0;i<4;i++) { switch(i) { case 0:C1=0;B1=0;A1=0;break; case 1:C1=0;B1=0;A1=1;break; case 2:C1=0;B1=1;A1=0;break; case 3:C1=0;B1=1;A1=1;break; } SHUMA=word[i]; delay(100); SHUMA=0x00; } } void Key(u8 dat) { if(K1==0) { delay(1000); if(K1==0) { At24CO2Write(0xa0,dat,1); } while(!K1); } if(K2==0) { delay(1000); if(K2==0) { num=At24CO2Read(0xa0,1); } while(!K2); } if(K3==0) { delay(1000); if(K3==0) { At24CO2Write(0xa2,dat,1); } while(!K3); } if(K4==0) { delay(1000); if(K4==0) { num=At24CO2Read(0xa2,1); } while(!K4); } if(K5==0) { delay(1000); if(K5==0) num++; while(!K5); } if(K6==0) { delay(1000); if(K6==0) num=0; while(!K6); } } void change() { display[0]=numer[num/1000]; display[1]=numer[(num%1000)/100]; display[2]=numer[(num%100)/10]; display[3]=numer[num%10]; } void main() { // SDA=1; // delay10us(); // SCL=0; // delay10us(); //// u8 addr = 0x66; // uchar addr1=0x66, addr2=0x88, dat1, dat2; // write(0xa2, addr2, 0); while(1) { Key(num); change(); shumaguan(display); } } void I2cStart() //开始函数，时钟信号始终为高，当数据线由高变低时开始 { SDA=1; delay10us(); SCL=1; delay10us(); SDA=0; delay10us(); SCL=0; delay10us(); } void I2cStop() //停止函数，时钟信号始终为高，当数据线由低变高时开结束 { SDA=0; delay10us(); SCL=1; delay10us(); SDA=1; delay10us(); } void I2cAck() { SDA=0; delay10us(); SCL=1; delay10us(); SCL=0; delay10us(); } void nack() { SDA = 1; //拉高SDA，发送非应答信号 Delay(); SCL = 1; //拉高SCL Delay(); SCL = 0; //再拉低完成非应答位，并保持住总线 } u8 I2cSend(u8 dat) { u8 i; for(i=0x80; i!=0; i>>=1) //从高位到低位依次进行 { if((dat&i) == 0) //该位的值依次输出到SDA上 SDA = 0; else SDA = 1; delay10us(); SCL = 1; //拉高SCL delay10us(); SCL = 0; //再拉低SCL完成一个位周期 } } u8 I2cRead() { u8 i, dat; SDA = 1; //确保主机释放SDA for(i=0x80; i!=0; i>>=1) //从高位到低位依次进行 { delay10us(); SCL = 1; //拉高SCL if(SDA == 0) //读取SDA的值 dat &= ~i; //为0时，dat中对应位清零 else dat |= i; //为1时，dat中对应位置1 delay10us(); SCL = 0; //再拉低SCL使从机发送出下一位 } return dat; } void At24CO2Write(u8 add,u8 dat,u8 addr) { I2cStart(); I2cSend(add); I2cAck(); I2cSend(addr); I2cAck(); I2cSend(dat); I2cAck(); I2cStop(); } u8 At24CO2Read(u8 add,u8 addr) { u8 num; I2cStart(); I2cSend(add); I2cAck(); I2cSend(addr); I2cAck(); I2cStart(); I2cSend(add+1); I2cAck(); num=I2cRead(); // nack(); I2cStop(); return num; }