单片机中断系统编程，4

iic

#ifndef _I2C_H
#define _I2C_H

#include<reg52.h>

sbit SCL=P2^1;//时钟线
sbit SDA=P2^0;//数据线

#include<iic.h>

void delay10us(void)   //10us
{
    unsigned char a,b;
    for(b=1;b>0;b--)
        for(a=2;a>0;a--);
}

void iicstart()//起始信号
{
	SDA=1;
	delay10us();
	SCL=1;
	delay10us();
	SDA=0;
	delay10us();
	SCL=0;
	delay10us();
}

void iicstop()//停止信号
{
	SDA=0;
	delay10us();
	SCL=1;
	delay10us();
	SDA=1;
	delay10us();
}

unsigned char iicsendbyte(unsigned char dat)//发信号
{								//返回值用来判断发送是否成功
	unsigned char a=0,b;
	for(a=0;a<8;a++)
	{
		SDA=dat>>7;
		dat<<=1;
		delay10us();
		SCL=1;
		delay10us();
		SCL=0;//高变低发一次，类似LED矩阵74ch595
		delay10us();
	}
	SDA=1;
	delay10us();
	SCL=1;
	while(SDA)//应答后SDA=0
	{
		b++;
		if(b>200)
		{
			SCL=0;
			delay10us();
			return 0;
		}
	}
	SCL=0;
	delay10us();
	return 1; 
}

unsigned char iicreadbyte()//读取函数（1字节）
{
unsigned char a=0,dat=0;
	SDA=1;
	delay10us();
	for(a=0;a<8;a++)
	{
		SCL=1；
		delay10us();
		dat<<=1;
		dat|=SDA;
		delay10us();
		SCL=0;
		delay10us();
	}
	return dat;
}
void AT24c02write(unsigned char addr,unsigned char dat)
{
	iicstart();
	iicsendbyte(0xa0);
	iicsendbyte(addr);
	iicsendbyte(dat);
	iicstop();
}

unsigned char AT24c02read(unsigned char addr)
{unsigned char num;
	iicstart();
	iicsendbyte(0xa0);
	iicsendbyte(addr);
	iicstart();
	iicsendbyte(0xa1);
	num=iicreadbyte();
	iicstop();
	return num;  
}

LED矩阵

#include<reg51.h>
#include<intrins.h>
typedef unsigned char u8;
typedef unsigned int u16;
sbit SER=P3^4;
sbit RCLK=P3^5;
sbit SRCLK=P3^6;
u8 x,y;
void hc595(u8 dat)
{
	RCLK=0;
	SRCLK=0;
	for(x=0;x<8;x++)
	{
		SER=(dat>>7);
		dat<<=1;//赋值 
		SRCLK=1;
		_nop_();
		_nop_();
		SRCLK=0;
	}
	RCLK=1;
	_nop_();
	_nop_();
	RCLK=0;
}
void main ()
{
	hc595(0x80);
	P0=0x7f;
		while(1);
}