/*********************************************************************
 *
 *                 1-Wire Communication Protocol
 *
 *********************************************************************
 * FileName:        1wire.c
 * Dependencies:
 * Processor:       PIC18
 * Complier:        MCC18 v3.13
 * Company:         Microchip Technology, Inc.
 *
 * Software License Agreement
 *
 * Copyright © 2004-2007 Microchip Technology Inc.  All rights reserved.
 *
 * Microchip licenses to you the right to use, copy and distribute Software 
 * only when embedded on a Microchip microcontroller or digital signal 
 * controller and used with a Microchip radio frequency transceiver, which 
 * are integrated into your product or third party product (pursuant to the 
 * sublicense terms in the accompanying license agreement).  You may NOT 
 * modify or create derivative works of the Software.  
 *
 *
 * You should refer to the license agreement accompanying this Software for 
 * additional information regarding your rights and obligations.
 *
 * SOFTWARE AND DOCUMENTATION ARE PROVIDED “AS IS” WITHOUT WARRANTY OF ANY 
 * KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION, ANY WARRANTY 
 * OF MERCHANTABILITY, TITLE, NON-INFRINGEMENT AND FITNESS FOR A PARTICULAR 
 * PURPOSE. IN NO EVENT SHALL MICROCHIP OR ITS LICENSORS BE LIABLE OR OBLIGATED 
 * UNDER CONTRACT, NEGLIGENCE, STRICT LIABILITY, CONTRIBUTION, BREACH OF 
 * WARRANTY, OR OTHER LEGAL EQUITABLE THEORY ANY DIRECT OR INDIRECT DAMAGES OR 
 * EXPENSES INCLUDING BUT NOT LIMITED TO ANY INCIDENTAL, SPECIAL, INDIRECT, 
 * PUNITIVE OR CONSEQUENTIAL DAMAGES, LOST PROFITS OR LOST DATA, COST OF 
 * PROCUREMENT OF SUBSTITUTE GOODS, TECHNOLOGY, SERVICES, OR ANY CLAIMS BY 
 * THIRD PARTIES (INCLUDING BUT NOT LIMITED TO ANY DEFENSE THEREOF), OR OTHER 
 * SIMILAR COSTS.
 *
 * Author               Date        Comment
 *~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 * Sasha     			12/20/07    Original
 ********************************************************************/

 /****** I N C L U D E S **********************************************************/
#include "Config.h"
#include "1wire.h"

//****** V A R I A B L E S ********************************************************/
unsigned char macro_delay;

/**********************************************************************
* Function:        void drive_OW_low (void)
* PreCondition:    None
* Input:		   None	
* Output:		   None	
* Overview:		   Configure the OW_PIN as Output and drive the OW_PIN LOW.	
***********************************************************************/
void drive_OW_low (void)
{
	OW_PIN_DIRECTION = OUTPUT;
	OW_WRITE_PIN=LOW;
}

/**********************************************************************
* Function:        void drive_OW_high (void)
* PreCondition:    None
* Input:		   None	
* Output:		   None	
* Overview:		   Configure the OW_PIN as Output and drive the OW_PIN HIGH.	
***********************************************************************/
void drive_OW_high (void)
{
	OW_PIN_DIRECTION = OUTPUT;
	OW_WRITE_PIN = HIGH;	
}

/**********************************************************************
* Function:        unsigned char read_OW (void)
* PreCondition:    None
* Input:		   None	
* Output:		   Return the status of OW pin.	
* Overview:		   Configure as Input pin and Read the status of OW_PIN 	
***********************************************************************/
unsigned char read_OW (void)
{
	unsigned char read_data=0;
	
	OW_WRITE_PIN = INPUT;

	 if (HIGH == OW_READ_PIN)
	 	read_data = SET;
	 else 	
		read_data = CLEAR;
		
	return read_data;
}

/**********************************************************************
* Function:        unsigned char OW_reset_pulse(void)
* PreCondition:    None
* Input:		   None	
* Output:		   Return the Presense Pulse from the slave.	
* Overview:		   Initialization sequence start with reset pulse.
*				   This code generates reset sequence as per the protocol
***********************************************************************/
unsigned char OW_reset_pulse(void)

{
	unsigned char presence_detect;
	
  	drive_OW_low(); 				// Drive the bus low
 	
 	wait(DELAY_240Us);	  			// delay 480 microsecond (us)
	wait(DELAY_240Us);		

 	drive_OW_high ();  				// Release the bus
	
	wait(DELAY_70Us);				// delay 70 microsecond (us)
	
	presence_detect = read_OW();	//Sample for presence pulse from slave

 	wait(DELAY_205Us);	  			// delay 410 microsecond (us)
	wait(DELAY_205Us);		
	
	drive_OW_high ();		    	// Release the bus
	
	return presence_detect;
}	

/**********************************************************************
* Function:        void OW_write_bit (unsigned char write_data)
* PreCondition:    None
* Input:		   Write a bit to 1-wire slave device.
* Output:		   None
* Overview:		   This function used to transmit a single bit to slave device.
*				   
***********************************************************************/

void OW_write_bit (unsigned char write_bit)
{
	if (write_bit)
	{
		//writing a bit '1'
		drive_OW_low(); 				// Drive the bus low
		wait(DELAY_6Us);				// delay 6 microsecond (us)
		drive_OW_high ();  				// Release the bus
		wait(DELAY_64Us);				// delay 64 microsecond (us)
	}
	else
	{
		//writing a bit '0'
		drive_OW_low(); 				// Drive the bus low
		wait(DELAY_60Us);				// delay 60 microsecond (us)
		drive_OW_high ();  				// Release the bus
		wait(DELAY_10Us);				// delay 10 microsecond for recovery (us)
	}
}	


/**********************************************************************
* Function:        unsigned char OW_read_bit (void)
* PreCondition:    None
* Input:		   None
* Output:		   Return the status of the OW PIN
* Overview:		   This function used to read a single bit from the slave device.
*				   
***********************************************************************/

unsigned char OW_read_bit (void)
{
	unsigned char read_data; 
	//reading a bit 
	drive_OW_low(); 						// Drive the bus low
	wait(DELAY_6Us);						// delay 6 microsecond (us)
	drive_OW_high ();  						// Release the bus
	wait(DELAY_9Us);						// delay 9 microsecond (us)

	read_data = read_OW();					//Read the status of OW_PIN

	wait(DELAY_55Us);						// delay 55 microsecond (us)	
	return read_data;
}

/**********************************************************************
* Function:        void OW_write_byte (unsigned char write_data)
* PreCondition:    None
* Input:		   Send byte to 1-wire slave device
* Output:		   None
* Overview:		   This function used to transmit a complete byte to slave device.
*				   
***********************************************************************/
void OW_write_byte (unsigned char write_data)
{
	unsigned char loop;
	
	for (loop = 0; loop < 8; loop++)
	{
		OW_write_bit(write_data & 0x01); 	//Sending LS-bit first
		write_data >>= 1;					// shift the data byte for the next bit to send
	}	
}	

/**********************************************************************
* Function:        unsigned char OW_read_byte (void)
* PreCondition:    None
* Input:		   None
* Output:		   Return the read byte from slave device
* Overview:		   This function used to read a complete byte from the slave device.
*				   
***********************************************************************/

unsigned char OW_read_byte (void)
{
	unsigned char loop, result=0;
	
	for (loop = 0; loop < 8; loop++)
	{
		
		result >>= 1; 				// shift the result to get it ready for the next bit to receive
		if (OW_read_bit())
		result |= 0x80;				// if result is one, then set MS-bit
	}
	return result;					
}	

/********************************************************************************************
                  E N D     O F     1 W I R E . C  
*********************************************************************************************/
#ifndef _Config_H
#define _Config_H


//******* D E F I N I T I O N S ************************************************/
#define CLK_FREQ_25000000 		 	0   				 //25MHz
#define CLK_FREQ_24000000 			0	   				 //24MHz
#define CLK_FREQ_20000000 			1   				 //20MHz
#define CLK_FREQ_16000000 			0   				 //16MHz
#define CLK_FREQ_12000000			0   				 //12MHz

#if((CLK_FREQ_25000000+CLK_FREQ_24000000+CLK_FREQ_20000000+CLK_FREQ_16000000+CLK_FREQ_12000000) != 1)
#error Select One Frequency for 1Us Delay Calculation.
#endif

//**********************************************************************
//This wait MACRO gives 1Us delay depending upon clock Speed Select;
//Wait_delay (200) generates a 200Us.
//			  loop:	  nop\							// 1 INST cycle
//					  nop\							// 1 INST cycle
//					  nop\							// 1 INST cycle
//					  decfsz macro_delay,1,1\       // 1 or 3INST cycle
//					  bra loop\						// 2 INST cycle
//**********************************************************************

//**********************************************************************
//#define CLOCK_FREQUENCY  	25000000   				 //25MHz
//Note: 1 INST Cycle = ((1/ CLOCK_SPEED) * 4) = (1/25000000)*4 = 0.16Us
//		Total INST Cycle in a loop = 0.16*6 = 0.96 ~ 1Us.
//**********************************************************************
#if(CLK_FREQ_25000000)
		#define wait(a) _asm movlw a\
					  movwf macro_delay,1\
			  loop:	  nop\
					  nop\
					  nop\
					  decfsz macro_delay,1,1\
					  bra loop\
					 _endasm
					 
		#define BAUD_RATE	39
//**********************************************************************
//#define CLOCK_FREQUENCY  	24000000   				 //24MHz
//Note: 1 INST Cycle = ((1/ CLOCK_SPEED) * 4) = (1/24000000)*4 = 0.1667Us
//		Total INST Cycle in a loop = 0.1667*6 = 1.0007 ~ 1Us.
//**********************************************************************

#elif (CLK_FREQ_24000000)
		#define wait(a) _asm movlw a\
					  movwf macro_delay,1\
			  loop:	  nop\
					  nop\
					  nop\
					  decfsz macro_delay,1,1\
					  bra loop\
					 _endasm

		#define BAUD_RATE	38
//**********************************************************************
//#define CLOCK_FREQUENCY  	20000000   				 //20MHz
//Note: 1 INST Cycle = ((1/ CLOCK_SPEED) * 4) = (1/20000000)*4 = 0.2Us
//		Total INST Cycle in a loop = 0.2*5 = 1.00 ~ 1Us.
//**********************************************************************

#elif (CLK_FREQ_20000000)
		#define wait(a) _asm movlw a\
					  movwf macro_delay,1\
			  loop:	  nop\
					  nop\
					  decfsz macro_delay,1,1\
					  bra loop\
					 _endasm

	    #define BAUD_RATE	31
//**********************************************************************
//#define CLOCK_FREQUENCY  	16000000   				 //16MHz
//Note: 1 INST Cycle = ((1/ CLOCK_SPEED) * 4) = (1/16000000)*4 = 0.25Us
//		Total INST Cycle in a loop = 0.25*4 = 1.00 ~ 1Us.
//**********************************************************************


#elif (CLK_FREQ_16000000)
		#define wait(a) _asm movlw a\
					  movwf macro_delay,1\
			  loop:	  nop\
					  decfsz macro_delay,1,1\
					  bra loop\
				 _endasm


	    #define BAUD_RATE	25
//**********************************************************************
//#define CLOCK_FREQUENCY  	12000000   				 //12MHz
//Note: 1 INST Cycle = ((1/ CLOCK_SPEED) * 4) = (1/12000000)*4 = 0.3333Us
//		Total INST Cycle in a loop = 0.33333*3 = 0.9999 ~ 1Us.
//**********************************************************************


#elif (CLK_FREQ_12000000)
		#define wait(a) _asm movlw a\
					  movwf macro_delay,1\
			  loop:	  decfsz macro_delay,1,1\
					  bra loop\
					 _endasm
					 
		#define BAUD_RATE	18
					
#endif


//*************************************************************************/



/******* G E N E R I C   D E F I N I T I O N S ************************************************/

#define	HIGH	1
#define	LOW		0
#define	OUTPUT	0
#define	INPUT 	1
#define	SET		1
#define	CLEAR	0


/**PORT D E F I N I T I O N S ****************************************************/

//UART PORT DEFINITIONS
#define UART_RX_DIRECTION   TRISCbits.TRISC7
#define UART_TX_DIRECTION   TRISCbits.TRISC6
#define UART_RX_STATUS		RCSTA
#define UART_TX_STATUS		TXSTA

//ONE WIRE PORT PIN DEFINITION
///****************************************************
// This Configuration is required to make any PIC MicroController
// I/O pin as Open drain to drive 1-wire.
///****************************************************
#define OW_PIN_DIRECTION 	LATBbits.LATB2
#define OW_WRITE_PIN  		TRISBbits.TRISB2
#define OW_READ_PIN			PORTBbits.RB2

/******* G E N E R I C   D E F I N I T I O N S ************************************************/

#define DELAY_6Us	6
#define DELAY_9Us	9
#define DELAY_10Us	10
#define DELAY_55Us	55
#define DELAY_60Us	60
#define DELAY_64Us	64
#define DELAY_70Us	70
#define DELAY_205Us	205			// DELAY_410Us = DELAY_205Us + DELAY_205Us
#define DELAY_240Us	240			// DELAY_480Us = DELAY_240Us + DELAY_240Us // since the variable is declared as unsigned char




/**************************************************************
	 function definition
**************************************************************/
void initEUSART(void);                 
void USART_RxTx(void);
void high_isr(void);
void low_isr(void);

/***********************************************************
   V A R I A B L E S
************************************************************/


#endif