i2c.rar_51 I2C_i2c_i2c 51_模拟I2C

#include<reg52.h> #define uchar unsigned char sbit scl=P3^3; sbit sda=P3^4; void delay1(uchar x) { uchar i,j; for(i=x;i>0;i--) for(j=100;j>0;j--); } void delay() {;;} void start() //开始 { sda=1; delay(); scl=1; delay(); sda=0; delay(); } void stop() //停止 { sda=0; delay(); scl=1; delay(); sda=1; delay(); } void respons() //应答 { uchar i; scl=1; while(sda==1&&i<250) i++; scl=0; delay(); } void init() { scl=1; sda=1; } void write_byte(uchar date) //写一个字节 { uchar temp,j; temp=date; for(j=0;j<8;j++) { temp=temp<<1; scl=0; delay(); sda=CY; delay(); scl=1; delay(); ; } scl=0; delay(); sda=1; delay(); } uchar read_byte() { uchar i,j,k; scl=0; delay(); sda=1; delay(); for(i=0;i<8;i++) { scl=1; delay(); j=sda; k=(k<<1)|j; scl=0; delay(); } return k; } void main() { init(); start(); write_byte(0xa0); respons(); write_byte(3); respons(); write_byte(0xA5); respons(); stop(); delay1(100); start(); write_byte(0xa0); respons(); write_byte(3); respons(); start(); write_byte(0xa1); respons(); P0=read_byte(); while(1); }