i2c-slave.mod.c

#define MAX_BUFFER 32


// SLAVE
void I2C_SlaveInit(unsigned char addr);
void I2C_SlaveInterruptRoutine(void);

typedef struct _I2C_BufferInfo{
	unsigned char size;
	unsigned char* buffer;
}I2C_BufferInfo;

void I2C_InputCallback(unsigned char buffer[], unsigned char count);
void I2C_OutputCallback(I2C_BufferInfo* bufferInfo);

// STRUCTURES

typedef struct _I2C_BaseData{
	char size;
	unsigned char type;
} I2C_BaseData;


typedef struct _I2C_SingleChangeData{
	I2C_BaseData i2cbase;
	char index;
	char state;
} I2C_SingleChangeData;


typedef struct _I2C_UnitInfo{
	I2C_BaseData i2cbase;
	char inputs;
	char outputs;
}I2C_UnitInfo;


typedef struct _ARP {
	unsigned long UDID;
	unsigned char I2CAddress;
} ARP_INFO;


unsigned char inputBuffer[MAX_BUFFER];
I2C_BufferInfo bufferInfo;
//char* bufferData;
//char expectedWriteSize = 0;





/****************************************************************************
 * Function:
 *   static void I2C_SlaveInit(unsigned char addr)
 *
 * Description:
 *   This routine initializes I2C in slave mode.
 *
 *
 * Preconditions:
 *   None
 *
 * Parameters:
 *   None
 *
 * Returns:
 *   None
 *
 * Remarks:
 *   None
 *
 ****************************************************************************/
void I2C_SlaveInit(unsigned char addr){
	char temp;
	SSP1CON1bits.WCOL = 0;
	SSP1CON1bits.SSPOV = 0;
	SSP1CON1bits.SSPEN = 0;
	SSP1CON1bits.CKP = 1;
	SSP1CON1bits.SSPM3 = 0;
	SSP1CON1bits.SSPM2 = 1;
	SSP1CON1bits.SSPM1 = 1;
	SSP1CON1bits.SSPM0 = 0;
	SSP1CON2bits.GCEN = 0;
	SSP1CON2bits.RCEN = 0;
	SSP1CON2bits.RSEN = 0;
	SSP1CON2bits.SEN = 1;
	//I2C_AHEN = 1;
	//I2C_SDAHT = 1;
	SSP1CON2bits.ACKSTAT = 0;
	SSP1CON2bits.ACKDT = 0;
	SSP1CON2bits.ACKEN = 0;
	SSP1CON2bits.PEN = 0;
  	SSP1ADD  = addr;
    SSP1STATbits.SMP     = 1;     			// Slew Rate Control Disabled (1Mhz)
	temp    	= SSP1BUF;
    PIR1bits.SSPIF   = 0;
    PIE1bits.SSPIE   = 1;
    SSP1CON1bits.SSPEN   = 1;        		// Enable SSP
}

/****************************************************************************
 * Function:
 *   void I2C_SlaveInterruptRoutine(void)
 *
 * Description:
 *   This routine should be called when an interrupt was generated to
 *   check if it was I2C-related
 *
 *
 * Preconditions:
 *   None
 *
 * Parameters:
 *   None
 *
 * Returns:
 *   None
 *
 * Remarks:
 *   None
 *
 ****************************************************************************/
void I2C_SlaveInterruptRoutine(void){
	if(PIR1bits.SSPIF && PIE1bits.SSPIE){
		char SSP_status = (SSP1STAT & 0b00101101); 	// Mask out State bits
		char Temp;
		static char Widx = 0;
		static char Ridx = 0;
		//LED_INT_B_IO = !LED_INT_B_IO;
		switch(SSP_status)
		{
			case 0b00001001: 				// I2C master write last byte was an address byte  0 0 A 0 S W 0 BF
				if(SSP1CON1bits.SSPOV){						// Recive overflow
					SSP1CON1bits.SSPOV = 0;
				}
				Temp = SSP1BUF;				// Read out buffer to clear BF flag
				Widx = 0;
				break;

			//case I2C_Write_Data2:
			case 0b00101001: 				// I2C master write last byte was a data byte   0 0 D 0 S W 0 BF
				if(SSP1CON1bits.SSPOV){						// Recive overflow
					SSP1CON1bits.SSPOV = 0;
				}
				if( Widx >= sizeof(I2C_BaseData)){
					I2C_BaseData* i2cbase = (I2C_BaseData*)&inputBuffer;
					if(i2cbase->size == Widx){
						Temp = SSP1BUF;				// Read out buffer to clear BF flag
					}else{
						inputBuffer[Widx++] = SSP1BUF;
					}
					if(i2cbase->size == Widx){
						I2C_InputCallback(inputBuffer, Widx);
					}	
				}else{
					inputBuffer[Widx++] = SSP1BUF;// Store data in buffer
				}
				break;

			case 0b00001101: 					    // I2C master read last byte was an address byte   0 0 A 0 S R 0 0
			case 0b00001100: 					// I2C master read last byte was an address byte    0 0 A 0 S R 0 0
				I2C_OutputCallback(&bufferInfo);
				SSP1BUF = bufferInfo.buffer[0]; 	// Write data to I2C
				Ridx = 1;
				break;

			case 0b00101101:  // I2C master read last byte was a data byte   0 0 D 0 S R 0 0
			case 0b00101100:  // I2C master read last byte was a data byte   0 0 D 0 S R 0 0
				if(Ridx == bufferInfo.size){ 		// Prevent reading beond buffer
					SSP1BUF = 0;					// Write dummy data to I2C
				}else{
					SSP1BUF = bufferInfo.buffer[Ridx++];// Write next data to I2C
				}
				if(SSP1CON1bits.WCOL){						// Writing while prev not
					SSP1CON1bits.WCOL = 0;
				}
				break;

			case 0b00101000: 				// I2C slave reset by nack from master   0 0 D 0 S W 0 0
				Temp  = SSP1BUF;					// Read out buffer to clear BF flag
				break;

			default:
				Temp = SSP1BUF;					// Read out buffer to clear BF flag
				break;
		}
		PIR1bits.SSPIF = 0;								// Clear activity flag
		SSP1CON1bits.CKP  = 1;						// Enable clock
	}
}