ignitionISRs.c

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/* FreeEMS - the open source engine management system
 *
 * Copyright 2008, 2009 Fred Cooke
 *
 * This file is part of the FreeEMS project.
 *
 * FreeEMS software is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * FreeEMS software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with any FreeEMS software.  If not, see http://www.gnu.org/licenses/
 *
 * We ask that if you make any changes to this file you email them upstream to
 * us at admin(at)diyefi(dot)org or, even better, fork the code on github.com!
 *
 * Thank you for choosing FreeEMS to run your engine!
 */


#define IGNITIONISRS_C
#include "inc/freeEMS.h"
#include "inc/interrupts.h"


/* Summary of intended ignition timing scheme
 *
 * Set TWO PIT timers based on a reference point (probably single cam trigger or optionally toggle bit based on missing tooth on crank)
 * Arm one PIT timer interrupt to trigger when we need to start dwelling
 * Arm the other PIT timer interrupt to trigger when we need to fire
 * Configure a variable to point to the next pin to turn on for dwell
 * Configure a variable to point to the next pin to turn off to fire
 * On PIT interrupt for dwell check to see that spark should have finished
 * If so, turn on coil to dwell
 * If not, reset dwell timer interrupt for end of spark event
 * On PIT interrupt for spark, turn off coil (amything else?)
 * Repeat for each cylinder.
 */

/* Further consideration to spark duration and dwell starting possibly needs to be done. */

/* further reading : ftp://ftp-sop.inria.fr/esterel/pub/papers/FDL99-camready.pdf section 4.1 has a nice diagram */


void IgnitionDwellISR(void)
{
    // clear flag
    PITTF = DWELL_ENABLE;

    // start dwelling asap
    PORTS_BA |= dwellStartMasks[nextDwellChannel];

    if(dwellQueueLength == 0){
        // turn off the int
        PITINTE &= DWELL_DISABLE;

        // disable channels
        PITCE &= DWELL_DISABLE;
    }else{
        // reduce queue length by one
        dwellQueueLength--;

        // increment channel counter to next channel
        if(nextDwellChannel < (fixedConfigs1.engineSettings.combustionEventsPerEngineCycle - 1)){
            nextDwellChannel++; // if not the last channel, increment
        }else{
            nextDwellChannel = 0; // if the last channel, reset to zero
        }

        // if the queue length after decrement is greater than 0 then we need to load the timer, if it is zero and we decremented, the timer was already loaded.
        if(dwellQueueLength > 0){
            if(dwellQueueLength > 8){ // TODO ???? why 8 ???? 12 or combustion events per... or ?
                //throw a nasty error of some sort for index out of range issue that should never occur (for now just light a LED)
                PORTS |= 0x20;
            }else{
                // load the timer if the index is good
                PITLD0 = queuedDwellOffsets[dwellQueueLength - 1];
            }
        }
    }

    // blink a led
    PORTS ^= 0x80;
}


void IgnitionFireISR(void)
{
    // clear flag
    PITTF = IGNITION_ENABLE;

    // fire the coil asap
    PORTS_BA &= ignitionMasks[nextIgnitionChannel];

    if(ignitionQueueLength == 0){
        // turn off the int
        PITINTE &= IGNITION_DISABLE;

        // disable channels
        PITCE &= IGNITION_DISABLE ;
    }else{
        // reduce queue length by one
        ignitionQueueLength--;

        // increment channel counter to next channel
        if(nextIgnitionChannel < (fixedConfigs1.engineSettings.combustionEventsPerEngineCycle - 1)){
            nextIgnitionChannel++; // if not the last channel, increment
        }else{
            nextIgnitionChannel = 0; // if the last channel, reset to zero
        }

        // if the queue length after decrement is greater than 0 then we need to load the timer, if it is zero and we decremented, the timer was already loaded.
        if(ignitionQueueLength > 0){
            if(ignitionQueueLength > fixedConfigs1.engineSettings.combustionEventsPerEngineCycle){ // TODO as above!!!!!!!!!!
                //throw a nasty error of some sort for index out of range issue that should never occur (for now just light a LED)
                PORTS |= 0x10;
            }else{
                // load the timer if the index is good
                PITLD0 = queuedIgnitionOffsets[ignitionQueueLength - 1];
            }
        }
    }

    // blink a led
    PORTS ^= 0x40;
}

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