如果有现成的程序模块，那么编程将会变得更加简单，而且可以直接改程序实现自己想要的功能。下面我给大家发一个ADXL345的通讯源程序。

#include 

//Device Address for ADXL345
//#define I2CWRITEADDR 0x3A			//I2C Address for Wirte, Highing the SDO of ADXL345
//#define I2CREADADDR  0x3B			//I2C Address for Read
#define		I2CWRITEADDR	0xA6	//I2C Address for Wirte, Grouding the SDO of ADXL345
#define		I2CREADADDR		0xA7	//I2C Address for Read

//I2C Process Step, Used for ADuC702X I2C Master
#define		I2C_IDLE    		0	//I2C Idle
#define		I2C_WRITE_ADDRESS  	1	//Write 1 Byte
#define		I2C_WRITE_DATA  	2	//Write 2 Byte
#define		I2C_SET_ADDRESS	 	3	//Set I2C Read Register Address

unsigned	char	I2CWriteValue;		//Data to Write 
unsigned	char	ReadRegister;		//data read back from register
unsigned	char	Status = I2C_IDLE;  //I2C process step, initialize with Idle
unsigned	char	DataBuffer[8];
unsigned	char	CountReceiveNumber;		  

//write "WriteValue" to "RegisterAddr" of ADXL345
void I2C_WRITE_REGISTER(unsigned char RegisterAddr, unsigned char WriteValue) 
{
    Status = I2C_WRITE_ADDRESS;		//Write Device Address
	I2CWriteValue = WriteValue;		//Set  Writevalue
	I2C1ADR = I2CWRITEADDR;			//Set device address for I2C write
	I2C1MTX = RegisterAddr;			//Set regsiter address

	while(I2C_IDLE != Status)		//Wait until I2C command finish 
	{;}
}

// Set register address for I2C read command
void I2C_SET_READ_ADDR(unsigned char RegisterAddr) 
{
	Status = I2C_SET_ADDRESS;		//Set I2C read register address
	I2C1ADR = I2CWRITEADDR;			//Set device address for I2C write
	I2C1MTX = RegisterAddr;			//Set regsiter address

	while (I2C_IDLE != Status)		//Wait until I2C command finish 
	{;}
}

//Read register from ADXL345
void I2C_READ_REGISTER(unsigned char RegisterStartAddress, unsigned char NumberOfRegisters)
{
	I2C1CNT = NumberOfRegisters - 1;		// Read NumberOfRegisters bytes one time.
	CountReceiveNumber = 0;			
	I2C_SET_READ_ADDR(RegisterStartAddress);//Set I2C read register start address
	Status = NumberOfRegisters;				//I2C read
	I2C1ADR = I2CREADADDR;					//Set device address for I2C read
     	
	while (I2C_IDLE != Status)				//Wait until I2C command finish
	{;}
}       

//I2C Interrupt

void FIQ_Handler(void) __fiq      
{
	// Master Transmit  
	if(((I2C1MSTA & 0x4) == 0x4) && (Status == I2C_WRITE_ADDRESS))	//Register address has been send out, then send the configuration data
	{
		Status = I2C_WRITE_DATA;
		I2C1MTX = I2CWriteValue;
	}		
	else if(((I2C1MSTA & 0x4) == 0x4) && (Status == I2C_WRITE_DATA))//Register data has been send out, write command finished
	{						  
	    Status = I2C_IDLE;
	}	
	else if(((I2C1MSTA & 0x4) == 0x4) && (Status == I2C_SET_ADDRESS))//Set I2C read register address finished
	{
	    Status = I2C_IDLE;
	}
    // Master Receive    
	else if (((I2C1MSTA & 0x8) == 0x8) && (Status != 0))			//Receive a byte
	{
		Status--;
		DataBuffer[CountReceiveNumber] = I2C1MRX;
		CountReceiveNumber++;	   	  
	}     
} 
void xl345Write(unsigned char count, unsigned char regaddr, unsigned char *buf)
{
	unsigned	char	iTemp = 0;
	for(iTemp=0;iTemp