This file is part of OneWire routines

by Isaac Marino Bavaresco

/*============================================================================*/
/*
 Copyright (c) 2016-2019, Isaac Marino Bavaresco
 All rights reserved.
 isaacbavaresco@yahoo.com.br

 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions are met:
     * Redistributions of source code must retain the above copyright
       notice, this list of conditions and the following disclaimer.
     * Neither the name of the author nor the
       names of its contributors may be used to endorse or promote products
       derived from this software without specific prior written permission.

 THIS SOFTWARE IS PROVIDED BY THE AUTHOR ''AS IS'' AND ANY
 EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
 DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*============================================================================*/
#include <string.h>
#include <xc.h>
#include "OneWire.h"
#include "OneWireHAL-PIC16F.h"
#include "Delay.h"
/*============================================================================*/
#define CONVERT_us_TO_TCY(t)    ((unsigned char)((t)*2.5))
/*============================================================================*/
#if         defined USE_INLINE
static inline void SetTimer( unsigned char t )
    {
    T2CONbits.TMR2ON= 0;
    PR2             = CONVERT_us_TO_TCY( t );
    TMR2            = 0;
    PIR1bits.TMR2IF = 0;
    }
#else   /*  defined USE_INLINE */
#define SetTimer(t) do{T2CONbits.TMR2ON= 0;PR2=CONVERT_us_TO_TCY( t );TMR2=0;PIR1bits.TMR2IF=0;}while(0)
#endif  /*  defined USE_INLINE */
/*============================================================================*/
#if         defined USE_INLINE
static inline void StartTimer( void )
    {
    T2CONbits.TMR2ON= 1;
    }
#else   /*  defined USE_INLINE */
#define StartTimer() do{T2CONbits.TMR2ON= 1;}while(0)
#endif  /*  defined USE_INLINE */
/*============================================================================*/
#if         defined USE_INLINE
static inline int TimerExpired( void )
    {
    return PIR1bits.TMR2IF;
    }
#else   /*  defined USE_INLINE */
#define TimerExpired() (PIR1bits.TMR2IF)
#endif  /*  defined USE_INLINE */
/*============================================================================*/
#if         defined USE_INLINE
static inline void EnterCritical( void )
    {
    INTCONbits.GIE  = 0;
    }
#else   /*  defined USE_INLINE */
#define EnterCritical() do{INTCONbits.GIE=0;}while(0)
#endif  /*  defined USE_INLINE */
/*============================================================================*/
#if         defined USE_INLINE
static inline void ExitCritical( void )
    {
    INTCONbits.GIE  = 1;
    }
#else   /*  defined USE_INLINE */
#define ExitCritical() do{INTCONbits.GIE=1;}while(0)
#endif  /*  defined USE_INLINE */
/*============================================================================*/
/*============================================================================*/
#if         defined USE_INLINE
static inline void OneWirePullDownOn( void )
    {
    PORTAbits.RA0       = 1;
    };
#else   /*  defined USE_INLINE */
#define OneWirePullDownOn() do{PORTAbits.RA0=1;}while(0)
#endif  /*  defined USE_INLINE */
/*============================================================================*/
#if         defined USE_INLINE
static inline void OneWirePullDownOff( void )
    {
    PORTAbits.RA0       = 0;
    }
#else   /*  defined USE_INLINE */
#define OneWirePullDownOff() do{PORTAbits.RA0=0;}while(0)
#endif  /*  defined USE_INLINE */
/*============================================================================*/
#if         defined USE_INLINE
static inline void OneWirePullUpOn( void )
    {
    PORTAbits.RA3       = 0;
    };
#else   /*  defined USE_INLINE */
#define OneWirePullUpOn() do{PORTAbits.RA3=0;}while(0)
//#define   OneWirePullUpOn()
#endif  /*  defined USE_INLINE */
/*============================================================================*/
#if         defined USE_INLINE
static inline void OneWirePullUpOff( void )
    {
    PORTAbits.RA3       = 1;
    }
#else   /*  defined USE_INLINE */
#define OneWirePullUpOff() do{PORTAbits.RA3=1;}while(0)
//#define   OneWirePullUpOff()
#endif  /*  defined USE_INLINE */
/*============================================================================*/
#if         defined USE_INLINE

    #if         defined USE_COMPARATOR

        static inline unsigned bit OneWireQueryBus( void )
            {
            return CMCONbits.C2OUT;
            }

    #else   /*  defined USE_COMPARATOR */

        static inline unsigned bit OneWireQueryBus( void )
            {
            return PORTAbits.RA1;
            }

    #endif  /*  defined USE_COMPARATOR */

#else   /*  defined USE_INLINE */

    #if         defined USE_COMPARATOR
        #define OneWireQueryBus() (CMCONbits.C2OUT)
    #else   /*  defined USE_COMPARATOR */
        #define OneWireQueryBus() (PORTAbits.RA1)
    #endif  /*  defined USE_COMPARATOR */

#endif  /*  defined USE_INLINE */
/*============================================================================*/
/*============================================================================*/
/*============================================================================*/
onewirestatus_t OneWireReset( void )
    {
    onewireint_t    Result;

    if( !OneWireQueryBus() )
        return ONE_WIRE_STATUS_BUS_CONTENTION;

    SetTimer( 60 );
    OneWirePullDownOn();            /* A */
    Delay_us( 240 );
    Delay_us( 240 );
    EnterCritical();
    OneWirePullDownOff();           /* B */

    StartTimer();

    while( OneWireQueryBus() == 0 && !TimerExpired() )
        {}

    if( OneWireQueryBus() == 0 )
        return ONE_WIRE_STATUS_BUS_CONTENTION;

    OneWirePullUpOn();              /* E */
    Delay_us( 8 );
    OneWirePullUpOff();             /* F */
    Delay_us( 64 );
    Result  = (onewireint_t)OneWireQueryBus();    /* H */
    ExitCritical();
    Delay_us( 240 );
    OneWirePullUpOn();              /* J/K */
    Delay_us( 60 );
    OneWirePullUpOff();             /* L */
    Delay_us( 10 );                 /* M */

    if( !OneWireQueryBus() )
        return ONE_WIRE_STATUS_BUS_CONTENTION;

    return Result == 0 ? ONE_WIRE_STATUS_OK : ONE_WIRE_STATUS_NO_RESPONSE;
    }
/*============================================================================*/
onewirestatus_t OneWireWriteZero( void )
    {
    if( !OneWireQueryBus() )
        return ONE_WIRE_STATUS_BUS_CONTENTION;

    EnterCritical();
    OneWirePullDownOn();            /* A */
    Delay_us( 60 );
    OneWirePullDownOff();           /* B0 */
    Delay_us(  2 );
    OneWirePullUpOn();              /* C0 */
    Delay_us( 16 );
    OneWirePullUpOff();             /* D0 */
    ExitCritical();
    Delay_us(  2 );                 /* E0 */

    if( !OneWireQueryBus() )
        return ONE_WIRE_STATUS_BUS_CONTENTION;

    return ONE_WIRE_STATUS_OK;
    }
/*============================================================================*/
onewirestatus_t OneWireWriteOne( void )
    {
    if( !OneWireQueryBus() )
        return ONE_WIRE_STATUS_BUS_CONTENTION;

    EnterCritical();
    OneWirePullDownOn();            /* A */
    Delay_us(  4 );
    OneWirePullDownOff();           /* BR */
    Delay_us(  2 );
    OneWirePullUpOn();              /* D1 */
    ExitCritical();
    Delay_us( 67 );
    OneWirePullUpOff();             /* E1 */
    Delay_us(  2 );                 /* F1 */
    if( !OneWireQueryBus() )
        return ONE_WIRE_STATUS_BUS_CONTENTION;

    return ONE_WIRE_STATUS_OK;
    }
/*============================================================================*/
onewirestatus_t OneWireReadBit( void )
    {
    onewirestatus_t Result;

    if( !OneWireQueryBus() )
        return ONE_WIRE_STATUS_BUS_CONTENTION;

    SetTimer( 60 );

    EnterCritical();
    OneWirePullDownOn();            /* A */
    StartTimer();
    Delay_us(  4 );
    OneWirePullDownOff();           /* BR */
    Delay_us( 16 );
    Result  = OneWireQueryBus();    /* CR */

    while( OneWireQueryBus() == 0 && !TimerExpired() )
        {}

    if( OneWireQueryBus() == 0 )
        {
        ExitCritical();
        return ONE_WIRE_STATUS_BUS_CONTENTION;
        }

    OneWirePullUpOn();              /* F0 */
    ExitCritical();
    while( !TimerExpired() )
        {}
    OneWirePullUpOff();             /* G0 */
    Delay_us(  4 );                 /* H0 */

    if( !OneWireQueryBus() )
        return ONE_WIRE_STATUS_BUS_CONTENTION;

    return Result;
    }
/*============================================================================*/
onewirestatus_t OneWireInit( void )
    {
    PORTAbits.RA0       = 0;
    TRISAbits.TRISA0    = 0;

    PORTAbits.RA3       = 1;
    TRISAbits.TRISA3    = 0;

    TRISAbits.TRISA1    = 1;

#if         defined USE_COMPARATOR
    TRISAbits.TRISA2    = 1;
    VRCONbits.VRR       = 0;
    VRCONbits.VR        = 1;
    VRCONbits.VROE      = 0;
    VRCONbits.VREN      = 1;

    CMCONbits.CM        = 5;
    CMCONbits.C2INV     = 1;
#else   /*  defined USE_COMPARATOR */
    CMCON               = 0x07;
#endif  /*  defined USE_COMPARATOR */

    T2CONbits.TMR2ON    = 0;
    T2CONbits.TOUTPS    = 1;

    return ONE_WIRE_STATUS_OK;
    }
/*============================================================================*/