// File:  can18F66K80.c

// modified copy of can18f.c for use with the 18F66K80 family

/* *****************************************************************************
 * VSCP (Very Simple Control Protocol) 
 * http://www.vscp.org
 *
 * Version 0.03 2006-04-11
 * akhe@eurosource.se
 *
 * Based on Microchip application note AN738
 * Copyright by Microchip
 * Original Software License Agreement
 *
 * The software supplied herewith by Microchip Technology Incorporated
 * (the “Company”) for its PICmicro® Microcontroller is intended and
 * supplied to you, the Company’s customer, for use solely and
 * exclusively on Microchip PICmicro Microcontroller products. The
 * software is owned by the Company and/or its supplier, and is
 * protected under applicable copyright laws. All rights are reserved.
 *  Any use in violation of the foregoing restrictions may subject the
 * user to criminal sanctions under applicable laws, as well as to
 * civil liability for the breach of the terms and conditions of this
 * license.
 *
 * THIS SOFTWARE IS PROVIDED IN AN “AS IS” CONDITION. NO WARRANTIES,
 * WHETHER EXPRESS, IMPLIED OR STATUTORY, INCLUDING, BUT NOT LIMITED
 * TO, IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 * PARTICULAR PURPOSE APPLY TO THIS SOFTWARE. THE COMPANY SHALL NOT,
 * IN ANY CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL OR
 * CONSEQUENTIAL DAMAGES, FOR ANY REASON WHATSOEVER.
 *  
 * =============================================================================
 *          Changes Copyright (C) 2004-3007 Ake Hedman, eurosource
 * =============================================================================
 *
 * This software is provided 'as-is', without any express or implied
 * warranty.  In no event will the authors be held liable for any damages
 * arising from the use of this software.
 *
 * Permission is granted to anyone to use this software for any purpose,
 * including commercial applications, and to alter it and redistribute it
 * freely, subject to the following restrictions:
 *
 * 1. The origin of this software must not be misrepresented; you must not
 *    claim that you wrote the original software. If you use this software
 *    in a product, an acknowledgment in the product documentation would be
 *    appreciated but is not required.
 * 2. Altered source versions must be plainly marked as such, and must not be
 *    misrepresented as being the original software.
 * 3. This notice may not be removed or altered from any source distribution.
 * 
 * This file is part of VSCP - Very Simple Control Protocol
 * http://www.vscp.org
 *
 * ****************************************************************************/

#include <xc.h>
#include <stdbool.h>
#include "can18F66K80.h"

// Local prototypes
static void vscp18F_writeRegs( uint8_t* ptr, uint32_t val, BOOL bExtended );
static void vscp18F_readRegs( uint8_t* ptr, uint32_t *val, BOOL bExtended );

//
// CAN controller configuration
// ============================
//
// http://www.port.de/engl/canprod/sv_req_form.html
//
// CAN controller configuration
// ============================
//

#define VSCPNODE_CAN_SJW			1
#define VSCPNODE_CAN_BRP			9 // 7
#define VSCPNODE_CAN_PHSEG1			8
#define VSCPNODE_CAN_PHSEG2			6
#define VSCPNODE_CAN_PROPSEG                    1

//#define VSCPNODE_CAN_MASK_BUF1 		0x01ff0000  // Only class = 0
//#define VSCPNODE_CAN_MASK_BUF2 		0x01ff0000
#define VSCPNODE_CAN_MASK_BUF1 			0x0000000   // All clases
#define VSCPNODE_CAN_MASK_BUF2 			0x0000000

#define VSCPNODE_CAN_FILTER1_BUF1		0
#define VSCPNODE_CAN_FILTER2_BUF1		0
#define VSCPNODE_CAN_FILTER1_BUF2		0
#define VSCPNODE_CAN_FILTER2_BUF2		0
#define VSCPNODE_CAN_FILTER3_BUF2		0
#define VSCPNODE_CAN_FILTER4_BUF2		0

////////////////////////////////////////////////////////////////////////////////
// vscp18f_init
//

void vscp18f_init( BOOL bExtended )
{
	// Set CAN module into configuration mode
	vscp18f_cansetmode( CAN18F_MODE_CONFIG );

    // 32MHZ clock, 125kbps
    //BRGCON1 = 0x07; //b00000111
	//BRGCON2 = 0xAC;
	//BRGCON3 = 0x03;

    // 32MHZ clock, 250kbps
    // T1=12, T2=4, BTQ=16, Sample point=75,SWJ=1,bitrate=250,error=0%
    // Calculator: http://www.kvaser.com/en/support/bit-timing-calculator.html
    BRGCON1 = 0x03;
	BRGCON2 = 0xAC;
	BRGCON3 = 0x03;
	// Receive only valid extended messages
	// Receive buffer 0 overflow will write to buffer 1
	if ( bExtended ) {	
    	RXB0CON = 0x44;		// all = 0x64, extended = 0x44
        }
        else {
	RXB0CON = 0x64;         // all = 0x64, extended = 0x44
	}
        RXB1CON = RXB0CON;	// 0x40;

	// CANTX will drive VDD when receive
	CIOCON = 0x20;

	// Set Buffer1 Mask value
	vscp18f_setmask( CAN_MASK_B1, VSCPNODE_CAN_MASK_BUF1, true );

	// Set Buffer 2 Mask value
	vscp18f_setmask( CAN_MASK_B2, VSCPNODE_CAN_MASK_BUF2, true );

	// Set Buffer 1 Filter Values
	vscp18f_setfilter( CAN_FILTER_B1_F1, VSCPNODE_CAN_FILTER1_BUF1, true );
	vscp18f_setfilter( CAN_FILTER_B1_F2, VSCPNODE_CAN_FILTER2_BUF1, true );

	vscp18f_setfilter( CAN_FILTER_B2_F1, VSCPNODE_CAN_FILTER1_BUF2, true );
	vscp18f_setfilter( CAN_FILTER_B2_F2, VSCPNODE_CAN_FILTER2_BUF2, true );
	vscp18f_setfilter( CAN_FILTER_B2_F3, VSCPNODE_CAN_FILTER3_BUF2, true );
	vscp18f_setfilter( CAN_FILTER_B2_F4, VSCPNODE_CAN_FILTER4_BUF2, true);

	// Set CAN module into normal mode
	vscp18f_cansetmode( CAN18F_MODE_NORMAL );
}

////////////////////////////////////////////////////////////////////////////////
// vscp18f_cansetmode
//

void vscp18f_cansetmode( uint8_t opmode )
{
    CANCON = opmode;

    // Wait until set
    while( ( CANSTAT & 0b11100000 ) != opmode );
}

////////////////////////////////////////////////////////////////////////////////
// vscp18F_writeRegs
//

static void vscp18F_writeRegs( uint8_t* ptr, uint32_t val, BOOL bExtended )
{
    CAN_MESSAGE_ID *Value;
    Value =  ( CAN_MESSAGE_ID* )&val;

    if ( bExtended ) {
        // Extended Identifier
        *ptr = Value->BYTES.BYTE_3 >> 5;        	// Copy EID<23:21> to SIDH<2:0>
        *ptr |= Value->BYTES.BYTE_4 << 3;       	// Copy EID<28:24> to SIDH<7:3>
        ptr++;                                  	// Point to SIDL
        *ptr = (Value->BYTES.BYTE_3 << 3) & 0xE0; 	// Copy EID<20:18> to SIDL<7:5>
                                                	// mask out EID<17:16> bits
        *ptr |= 0b00001000;                     	// Set EXIDEN bit  to SIDL<3>
        *ptr |= Value->BYTES.BYTE_3 & 0x03;     	// Copy EID<17:16> to SIDL<1:0>
        ptr++;                                  	// Point to EIDH
        *ptr = Value->BYTES.BYTE_2;             	// Copy EID<15:8> to EIDH<7:0>
        ptr++;                                  	// Point to EIDL
        *ptr = Value->BYTES.BYTE_1;             	// Copy EID<7:0> to EIDL<7:0>		
    }
    else {
    	// Standard Identifier
        *ptr = Value->BYTES.BYTE_1 >> 3;        	// Copy SID<7:3> to SIDH<4:0>
        *ptr |= (Value->BYTES.BYTE_2 << 5);     	// Copy SID<10:8> to SIDH<7:5>
        ptr++;                                  	// Point to SIDL
        *ptr = Value->BYTES.BYTE_1 << 5;        	// Copy SID<2:0> to SIDL<7:5>    
    }
}

////////////////////////////////////////////////////////////////////////////////
// vscp18F_readRegs
//

static void vscp18F_readRegs( uint8_t* ptr, uint32_t *val, BOOL bExtended )
{
    CAN_MESSAGE_ID *Value;
    Value = (CAN_MESSAGE_ID*)val;

    if ( bExtended ) {
        // Extended Identifier
        Value->BYTES.BYTE_3 = (*ptr << 5);      	// Copy SIDH<2:0> to EID<23:21>
        Value->BYTES.BYTE_4 = (*ptr >> 3);      	// Copy SIDH<7:3> to EID<29:25>
        ptr++;                          			// Point to SIDL
        Value->BYTES.BYTE_3 |= (*ptr & 0x03);   	// Copy SIDH<1:0> to EID<17:16>
        // Bug-Fix NKR 11/20/00
        Value->BYTES.BYTE_3 |= ((*ptr & 0xe0) >> 3);    // Copy SIDL<7:6> to EID<20:18>
        ptr++;                          			// Point to EIDH
        Value->BYTES.BYTE_2 = *ptr;             	// Copy EIDH<15:8> to EID<15:8>
        ptr++;                                  	// Point to EIDL
        Value->BYTES.BYTE_1 = *ptr;             	// Copy EIDH<7:0> to EID<7:0>		
    }
    else {
    	// Standard Identifier
        Value->BYTES.BYTE_1 = (*ptr << 3);      	// Copy SIDH<4:0> to SID<7:3>
        Value->BYTES.BYTE_2 = *ptr >> 5;        	// Copy SIDH<7:5> to SID<10:8>
        ptr++;                                  	// Point to SIDL
        Value->BYTES.BYTE_1 |= (*ptr >> 5);     	// Copy SIDL<7:6> to SID<2:0>
        Value->BYTES.BYTE_3 = 0x00;
        Value->BYTES.BYTE_4 = 0x00;
    }
}

////////////////////////////////////////////////////////////////////////////////
// vscp18f_setmask
//

void vscp18f_setmask( uint8_t nmask, uint32_t val, BOOL bExtended )
{
     uint8_t *ptr;

    // Set base pointer
    if ( nmask == CAN_MASK_B1  ) {
        ptr = (uint8_t*)&RXM0SIDH;
    }
    else {
        ptr = (uint8_t*)&RXM1SIDH;
    }
    // Write to regs
    vscp18F_writeRegs( ptr, val, bExtended );
}

////////////////////////////////////////////////////////////////////////////////
// vscp18f_setfilter
//

void vscp18f_setfilter( uint8_t nfilter, uint32_t val, BOOL bExtended )
 {
    uint8_t *ptr;

    // Set base pointer
    switch ( nfilter ) {

    	case CAN_FILTER_B1_F1:
        	ptr = (uint8_t*)&RXF0SIDH;
        	break;

    	case CAN_FILTER_B1_F2:
        	ptr = (uint8_t*)&RXF1SIDH;
        	break;

    	case CAN_FILTER_B2_F1:
        	ptr = (uint8_t*)&RXF2SIDH;
        	break;

    	case CAN_FILTER_B2_F2:
        	ptr = (uint8_t*)&RXF3SIDH;
        	break;

    	case CAN_FILTER_B2_F3:
        	ptr = (uint8_t*)&RXF4SIDH;
        	break;

    	default:
        	ptr = (uint8_t*)&RXF5SIDH;
        	break;
    }
    // Write to regs
    vscp18F_writeRegs( ptr, val, bExtended );

}

////////////////////////////////////////////////////////////////////////////////
// vscp18f_sendMsg
//

BOOL vscp18f_sendMsg(  uint32_t id, uint8_t* data, uint8_t dlc, uint8_t flags )
{
    uint8_t i;
    uint8_t *ptr;

    // Find the first empty transmitter.
    if ( TXB0CONbits.TXREQ == 0 ) {
        // TxBuffer0 is available.  Set WIN bits to point to TXB0
        CANCON &= 0b11110001;
        CANCON |= 0b00001000;
    }
    else if ( TXB1CONbits.TXREQ == 0 ) {
        // TxBuffer1 is available. Set WIN bits to point to TXB1
        CANCON &= 0b11110001;
        CANCON |= 0b00000110;
    }
    else if ( TXB2CONbits.TXREQ == 0 ) {
        // TxBuffer2 is available.. Set WIN bits to point to TXB2
        CANCON &= 0b11110001;
        CANCON |= 0b00000100;
    }
    else {
        // uanble to send message - all buffers full
        return false;
	}

    //
    // Now that WIN has remapped RXB0 to empty buffer, simply
    // populate RXB0 buffer
    //

    // Set transmit priority.
    RXB0CON = flags & 0b00000011;

    // Populate Extended identifier information only if it is
    // desired.
    if ( flags & CAN_TX_XTD_FRAME  ) {
        vscp18F_writeRegs( (uint8_t*)&RXB0SIDH, id, true );
	}
    else {
        vscp18F_writeRegs( (uint8_t*)&RXB0SIDH, id, false );
	}

    RXB0DLC = dlc;

	// RTR
    if ( flags & CAN_TX_RTR_FRAME ) {
    	RXB0DLC |= 0b01000000;
	}

    // Populate data values.
    ptr = (uint8_t*)&RXB0D0;
    for ( i = 0; i < dlc; i++ ) {
    	ptr[ i ] = data[ i ];
	}

    //
    // Mark this buffer as ready to start transmit.
    // We are not using C bit field structure because RXB0 registers
    // are remapped to one of the empty transmit buffers and their
    // bit3 is not same as RXB0CON bit3.  To avoid confusion, in-line
    // assembly is used to directly set bit 3 of corresponding TXBnCON
    // register.
    //
    
     asm("bsf _RXB0CON,3");

    //
    // Restore CAN buffer mapping so that subsequent access to RXB0
    // buffers are to the real RXB0 buffer.
    //
    CANCON &= 0b11110001;

    return true;
}

////////////////////////////////////////////////////////////////////////////////
// vscp18f_readMsg
//

BOOL vscp18f_readMsg( uint32_t *id, uint8_t *data, uint8_t *dlc, uint8_t *flags )
{
    uint8_t i;
    uint8_t *ptr;
    BOOL lbIsItBuffer0;

    // Start with no error or flags set.
    *flags = 0x00;

    // Find which buffer is ready.
    if ( RXB0CONbits.RXFUL ) {
        // Buffer0 contains a message.
        CANCON &= 0b11110001;

        lbIsItBuffer0 = true;

        // Clear the received flag.
        PIR5bits.RXB0IF = 0;

        // Record and forget any previous overflow
	if ( COMSTATbits.RXB0OVFL ) {
            *flags |= CAN_RX_OVERFLOW;
            // errata...
            //COMSTATbits.RXB0OVFL = 0;
            asm ("BCF COMSTAT, 6, 0");
        }      
        if ( RXB0CONbits.RB0DBEN ) {
        *flags |= RXB0CON & 0b00000111;
        *flags &= 0x01;
        }
        else if ( RXB1CONbits.RXFUL ) {
        // RXBuffer1 is full
        CANCON &= 0b11110001;
        CANCON |= 0b00001010;

        lbIsItBuffer0 = false;

        // Clear the received flag
	PIR5bits.RXB1IF = 0;

        // Record and forget any previous overflow
	if ( COMSTATbits.RXB0OVFL ) {
            *flags |= CAN_RX_OVERFLOW;
            // errata...
            //COMSTATbits.RXB1OVFL = 0;
            asm ("BCF COMSTAT, 7, 0");
        }
        
        *flags |= RXB1CON & 0b00000111;
        if ( *flags < 0x02 )
        *flags |= CAN_RX_DBL_BUFFERED;
    }
    else {
        return false;
    }

    // Retrieve message length.
    *dlc = RXB0DLC & 0b00001111;

    // Determine whether this was RTR or not.
    if ( ( RXB0DLC & 0x40 ) ) {
        *flags |= CAN_RX_RTR_FRAME;
    }

    // Retrieve EIDX bytes only if this is extended message
    if ( RXB0SIDLbits.EXID ) {
        *flags |= CAN_RX_XTD_FRAME;

        vscp18F_readRegs( ( uint8_t* )&RXB0SIDH, id, true );
    }
    else {
        vscp18F_readRegs( ( uint8_t* )&RXB0SIDH, id, false );
	}

    // Get message data itself
    ptr = ( uint8_t* )&RXB0D0;
    for ( i = 0; i < *dlc; i++ ) {
        data[ i ] = ptr[ i ];
	}

    // Restore default RXB0 mapping.
    CANCON &= 0b11110001;

    // Record and Clear any previous invalid message bit flag.
    if ( PIR5bits.IRXIF ) {
        *flags |= CAN_RX_INVALID_MSG;
        PIR5bits.IRXIF = 0;
    }
    if ( lbIsItBuffer0 ) {
        RXB0CONbits.RXFUL = 0;
	}
    else {
        RXB1CONbits.RXFUL = 0;
	}
  }

  return true;
}