i2c.c

本程序已经调试通过

/**********************************************************************
* FileName:  i2c.c
**********************************************************************/
#if defined(__dsPIC33F__)
#include "p33fxxxx.h"
#endif

#include "i2c.h"

void InitI2C(void)
{
//	TRISAbits.TRISA2 = 0;//引脚配置
//	PORTAbits.RA2 = 0;
	
	ODCAbits.ODCA2 = 0;
	ODCGbits.ODCG2 = 0;
	ODCGbits.ODCG3 = 0;
		
	OpenI2C1(35);//使能I2C模块
}	 

/******************************************************************************
* This function configures the I2C module for enable bit
*******************************************************************************/
void OpenI2C1(unsigned int brg)
{
	I2C1BRG = brg;
	I2C1CONbits.I2CEN = 1;
}
/*********************************************************************
* This routine generates acknowledge condition during master receive.
*********************************************************************/
void AckI2C1(void)
{
	I2C1CONbits.ACKDT = 0;
	I2C1CONbits.ACKEN = 1;
}
/*********************************************************************
* This routine generates Start condition during master mode.
*********************************************************************/
void StartI2C1(void)
{
	IdleI2C1();
	I2C1CONbits.SEN = 1;	/* initiate Start on SDA and SCL pins */
}
/************************************************************************
* This routine provides the status whether the receive buffer is full by returning the RBF bit.
*************************************************************************/
char DataRdyI2C1(void)
{
     return I2C1STATbits.RBF;
}
/************************************************************************	
* This routine generates wait condition intil I2C bus is Idle.
*************************************************************************/
void IdleI2C1(void)
{
    /* Wait until I2C Bus is Inactive */
    while(I2C1CONbits.SEN || I2C1CONbits.PEN || I2C1CONbits.RCEN || 
          I2C1CONbits.ACKEN || I2C1STATbits.TRSTAT);	
}
/************************************************************************
* This routine reads predetermined data string length from the I2C bus.
*************************************************************************/
unsigned char MastergetsI2C1(unsigned char * rdptr, unsigned int length)
{
	while(length)/* Receive length bytes */
	{
		if(MasterReadI2C1(rdptr))return 1;/* save byte received */
		rdptr++;
		length--;
		if(length == 0)	/* If last char, generate NACK sequence */
		{
			I2C1CONbits.ACKDT = 1;
			I2C1CONbits.ACKEN = 1;
		}
		else			/* For other chars,generate ACK sequence */
		{
			I2C1CONbits.ACKDT = 0;
			I2C1CONbits.ACKEN = 1;
		}
		while(I2C1CONbits.ACKEN == 1);/* Wait till ACK/NACK sequence is over */
	}
	/* return status that number of bytes specified by length was received */
	return 0;
}
/***********************************************************************
* This routine is used to write out a string to the I2C bus.
* If write collision occurs,1 is sent. 
* If string is written and null char reached, 0 is returned.
************************************************************************/
unsigned char MasterputsI2C1(unsigned char * wrptr, unsigned char length)
{
	while(length)//transmit data until null char
	{
		if(MasterWriteI2C1(*wrptr) == 1)// write a byte
			return 1;//return with write collison error		
		wrptr++;
		length--;
	}
	return 0;			
}
/******************************************************************************
* This routine reads a single byte from the I2C Bus. 
* To enable master receive,RCEN bit is set.The RCEN bit is checked until it is cleared.
* When cleared,the receive register is full and it's contents are returned.                   
********************************************************************************/
unsigned char MasterReadI2C1(unsigned char *rdptr)
{
	unsigned int wait=0;
	IdleI2C1();
	I2C1CONbits.RCEN = 1;
	I2C1CONbits.ACKEN=0;//关应答使能
	while(!DataRdyI2C1())
	{
		if(wait<10000) wait++ ;                 
		else return 1;/* Time out, return number of byte/word to be read */
	}	
	*rdptr=I2C1RCV;
	I2C1STATbits.I2COV = 0;
	return 0;
}
/************************************************************************
* This routine is used to write a byte to the I2C bus.
* The input parameter data is written to the I2CTRN register. 
* If IWCOL bit is set,write collision has occured and 1 is returned, else 0 is returned.
*************************************************************************/
unsigned char MasterWriteI2C1(unsigned char data)
{
	unsigned int wait;
	IdleI2C1();//判I2C总线忙否   
	I2C1TRN = data;//寻址 
	wait=0;                    
	while(I2C1STATbits.ACKSTAT)//数据发送,并等待从器件的应答,否就等待循环
	{
		wait++;
		if(wait>5) return 1;
	}
	return 0;
}
/*********************************************************************
* This routine generates Restart condition during master mode.
*********************************************************************/
void RestartI2C1(void)
{ 
	IdleI2C1();
	I2C1CONbits.RSEN = 1;	/* initiate restart on SDA and SCL pins	*/
	while(I2C1CONbits.RSEN);
}
/*********************************************************************
* This routine generates Stop condition during master mode.
*********************************************************************/
void StopI2C1(void)
{
	IdleI2C1();
	I2C1CONbits.PEN = 1;	/* initiate Stop on SDA and SCL pins */
}
/*********************************************************************
* This routine disables the I2C1 module by clearing the I2CEN bit in I2C1CON register.
* The MI2C1 and SI2C1 interrupts are disabled and the corresponding IF flags are cleared
*********************************************************************/
void CloseI2C1(void)
{
	/* clear the I2CEN bit */
	I2C1CONbits.I2CEN = 0;
	
	/* clear the SI2C & MI2C Interrupt enable bits */
	_SI2C1IE = 0;
	_MI2C1IE = 0;
	
	/* clear the SI2C & MI2C Interrupt flag bits */
	_SI2C1IF = 0;
	_MI2C1IF = 0;
}