A:/eclipse/mhvlib/MHV_StepperMotor.cpp

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/* Copyright (c) 2011, Make, Hack, Void Inc
 * All rights reserved.
 *
 * 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.
 *  * Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *  * Neither the name of the Make, Hack, Void 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 COPYRIGHT HOLDERS AND CONTRIBUTORS "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 MAKE, HACK, VOID BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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 */

#include <MHV_StepperMotor.h>

MHV_StepperMotor::MHV_StepperMotor(MHV_RTC &rtc) :
                _position(0),
                _rtc(rtc),
                _moving(false),
                _stepperListener(NULL) {}

void MHV_StepperMotor::setPosition(int32_t      position) {
                _position = position;
}

int32_t MHV_StepperMotor::getPosition() {
        return _position;
}

bool MHV_StepperMotor::isMoving() {
        return _moving;
}

void MHV_StepperMotor::rotate(bool forward, float speed, int32_t until) {
        _forward = forward;
        _speed = speed;
        _until = until;

// Remove any current alarms
        _rtc.removeAlarm(this);

// Register the alarm with the RTC
        MHV_ALARM newAlarm;
        newAlarm.listener = this;
        _rtc.current(&(newAlarm.when));
        _started.milliseconds = newAlarm.when.milliseconds;
        _started.timestamp = newAlarm.when.timestamp;
        newAlarm.repeat.milliseconds = 1;
        newAlarm.repeat.timestamp = 0;

        _startPosition = _position;

        _moving = true;

        _rtc.addAlarm(&newAlarm);
}

void MHV_StepperMotor::alarm(const MHV_ALARM &alarm) {
        if (!_moving) {
                return;
        }

        MHV_TIMESTAMP elapsed;
        _rtc.elapsed(&_started, &elapsed);
// Reuse elapsed.timestamp to represent milliseconds elapsed
        elapsed.timestamp *= 1000;
        elapsed.timestamp += elapsed.milliseconds;

        int32_t expectedPosition = _startPosition + elapsed.timestamp * _speed / ((_forward) ? 1000 : -1000);

        if (expectedPosition != _position) {
                step(_forward);
                _position += (_forward) ? 1 : -1;
        }

        if (_until == _position) {
// We are done
                _speed = 0;
                _moving = false;
                _rtc.removeAlarm(this);
                if (_stepperListener) {
                        _stepperListener->moveComplete(_position);
                }
        }
}

void MHV_StepperMotor::registerListener(MHV_StepperListener &listener) {
        _stepperListener = &listener;
}

void MHV_StepperMotor::deregisterListener() {
        _stepperListener = NULL;
}