IIC总线协议的原始驱动代码与其实例应用代码编写

- 日理万妓 2022-05-08 03:50 178阅读 0赞

**原始驱动代码：**

//备注：该驱动代码针对8051芯片，晶振为12MHz的IIC驱动程序
    
    #include "intrins.h"
    
    #define somenop {_nop_();_nop_();_nop_();_nop_();_nop_();}    //这里根据时钟大小需要适当修改_nop_();个数，比如针对stc15芯片，需要将_nop_();的个数乘上8
    #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 */
    
    //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(bit 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;
    }

**实例应用代码编写：**

#include "intrins.h"
    #include "iic.h"
    
    #define somenop {_nop_();_nop_();_nop_();_nop_();_nop_();}    
    
    //总线引脚定义
    sbit SDA = P2^1;  /* 数据线 */
    sbit SCL = P2^0;  /* 时钟线 */
    
    //总线开始条件
    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(bit 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(uchar 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
    uchar 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;
    }
    
    //读写IIC的值
    uchar IIC_AD_Read(uchar add)	  //add为地址
    {
    	uchar temp;
    			
    	IIC_Start();   	//启动总线
    	IIC_SendByte(0x90);		//器件的地址
    	IIC_WaitAck();			//等待响应
    	IIC_SendByte(add);		 //读哪个通道的内容（add为通道地址）
    	IIC_WaitAck();
    	IIC_Stop();
    
    	IIC_Start();
    	IIC_SendByte(0x91);		//器件地址加1
    	IIC_WaitAck();
    	temp = IIC_RecByte();
    	IIC_Stop();
    
    	return temp;		//返回temp
    }
    
    //读EEPROM的值
    uchar IIC_EEPROM_Read(uchar add1)	  //add为地址
    {
    	uchar temp1;
    			
    	IIC_Start();   	//启动总线
    	IIC_SendByte(0xa0);		//EEPROM芯片的地址
    	IIC_WaitAck();			//等待响应
    	IIC_SendByte(add1);		 //读哪个通道的内容（add为通道地址）
    	IIC_WaitAck();
    	IIC_Stop();
    
    	IIC_Start();
    	IIC_SendByte(0xa1);
    	IIC_WaitAck();
    	temp1 = IIC_RecByte();
    	IIC_Stop();
    
    	return temp1;		//返回temp1
    }
    
    //将数值写入EEPROM
    void IIC_EEPROM_Write(uchar add2, uchar dat)
    {
    	IIC_Start();
    	IIC_SendByte(0xa0);    //选择EEPROM芯片地址
    	IIC_WaitAck();       //等待响应
    	IIC_SendByte(add2);	 //写地址
    	IIC_WaitAck();    //等待响应
    	IIC_SendByte(dat);     //对其进行写数据
    	IIC_WaitAck();	   //等待响应
    	IIC_Stop();		//写入成功，IIC停止
    }