蓝桥杯-官方驱动-iic

#ifndef _IIC_H
#define _IIC_H

#include "stc15f2k60s2.h"
#include "intrins.h"

#define somenop {_nop_();_nop_();_nop_();_nop_();_nop_();}
#define SlaveAddrW 0xA0
#define SlaveAddrR 0xA1

//总线引脚定义
sbit SDA = P2^1;  /* 数据线 */
sbit SCL = P2^0;  /* 时钟线 */

//函数声明
void IIC_Start(void); 
void IIC_Stop(void);  
void IIC_Ack(unsigned char ackbit); 
void IIC_SendByte(unsigned char byt); 
bit IIC_WaitAck(void);  
unsigned char IIC_RecByte(void); 

#endif

 蓝桥杯 官方驱动

/*
  程序说明: IIC总线驱动程序
  软件环境: Keil uVision 4.10 
  硬件环境: CT107单片机综合实训平台(12MHz)
  日    期: 2011-8-9
*/

#include "iic.h"

//总线启动条件
void IIC_Start(void)
{
	SDA = 1;
	SCL = 1;
	somenop;
	SDA = 0;
	somenop;
	SCL = 0;	
}

//总线停止条件
void IIC_Stop(void)
{
	SDA = 0;
	SCL = 1;
	somenop;
	SDA = 1;
}

//应答位控制
void IIC_Ack(unsigned char ackbit)
{
	if(ackbit) 
	{	
		SDA = 0;
	}
	else 
	{
		SDA = 1;
	}
	somenop;
	SCL = 1;
	somenop;
	SCL = 0;
	SDA = 1; 
	somenop;
}

//等待应答
bit IIC_WaitAck(void)
{
	SDA = 1;
	somenop;
	SCL = 1;
	somenop;
	if(SDA)    
	{   
		SCL = 0;
		IIC_Stop();
		return 0;
	}
	else  
	{ 
		SCL = 0;
		return 1;
	}
}

//通过I2C总线发送数据
void IIC_SendByte(unsigned char byt)
{
	unsigned char i;
	for(i=0;i<8;i++)
	{   
		if(byt&0x80) 
		{	
			SDA = 1;
		}
		else 
		{
			SDA = 0;
		}
		somenop;
		SCL = 1;
		byt <<= 1;
		somenop;
		SCL = 0;
	}
}

//从I2C总线上接收数据
unsigned char IIC_RecByte(void)
{
	unsigned char da;
	unsigned char i;
	
	for(i=0;i<8;i++)
	{   
		SCL = 1;
		somenop;
		da <<= 1;
		if(SDA) 
		da |= 0x01;
		SCL = 0;
		somenop;
	}
	return da;
}