ktechlab/src/electronics/switch.cpp

/***************************************************************************
 *   Copyright (C) 2005 by David Saxton                                    *
 *   david@bluehaze.org                                                    *
 *                                                                         *
 *   This program 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 2 of the License, or     *
 *   (at your option) any later version.                                   *
 ***************************************************************************/

#include "circuitdocument.h"
#include "component.h"
#include "ecnode.h"
#include "pin.h"
#include "resistance.h"
#include "simulator.h"
#include "switch.h"

#include <kdebug.h>
#include <tqtimer.h>

#include <cmath>
#include <stdlib.h> // for rand
#include <time.h>

Switch::Switch( Component * parent, Pin * p1, Pin * p2, State state )
{
	m_bouncePeriod_ms = 5;
	m_bBounce = false;
	m_bounceStart = 0;
	m_pBounceResistance = 0l;
	m_pP1 = p1;
	m_pP2 = p2;
	m_pComponent = parent;
	m_pStopBouncingTimer = new TQTimer( this );
	connect( m_pStopBouncingTimer, TQT_SIGNAL(timeout()), this, TQT_SLOT(stopBouncing()) );
	
	// Force update
	m_state = (state == Open) ? Closed : Open;
	setState(state);
}


Switch::~ Switch( )
{
	if (m_pP1)
		m_pP1->setSwitchConnected( m_pP2, false );
	
	if (m_pP2)
		m_pP2->setSwitchConnected( m_pP1, false );
}


void Switch::setState( State state )
{
	if ( m_state == state )
		return;
	
	m_state = state;
	
	if ( m_bBounce )
		startBouncing();
	else
	{
		// I'm being lazy...calling stopBouncing will connect the stuff
		stopBouncing();
	}
}


void Switch::setBounce( bool bounce, int msec )
{
	m_bBounce = bounce;
	m_bouncePeriod_ms = msec;
}


void Switch::startBouncing()
{
	if ( m_pBounceResistance )
	{
		// Already active?
		return;
	}
	
	CircuitDocument * cd = m_pComponent->circuitDocument();
	if ( !cd )
		return;
	
// 	kdDebug() << k_funcinfo << endl;
	
	m_pBounceResistance = m_pComponent->createResistance( m_pP1, m_pP2, 10000 );
	m_bounceStart = Simulator::self()->time();
	Simulator::self()->attachSwitch( this );
// 	kdDebug() << "m_bounceStart="<<m_bounceStart<<" m_bouncePeriod_ms="<<m_bouncePeriod_ms<<endl;
	
	// initialize random generator
	srand ( time(NULL) );
	
	// Give our bounce resistor an initial value
	bounce();
}


void Switch::bounce()
{
	int bounced_ms = (( Simulator::self()->time() - m_bounceStart ) * 1000) / LOGIC_UPDATE_RATE;
	if ( bounced_ms >= m_bouncePeriod_ms )
	{
		if ( !m_pStopBouncingTimer->isActive() )
			m_pStopBouncingTimer->start( 0, true );
		return;
	}
	
	double g = double(rand())/double(RAND_MAX);
	
	// 4th power of the conductance seems to give a nice distribution
	g = g * g * g * g;
	
	m_pBounceResistance->setConductance( g );
}


void Switch::stopBouncing()
{
	Simulator::self()->detachSwitch( this );
	m_pComponent->removeElement( m_pBounceResistance, true );
	m_pBounceResistance = 0l;
	
	bool connected = (m_state == Closed);
	
	if ( m_pP1 && m_pP2 )
	{
		m_pP1->setSwitchConnected( m_pP2, connected );
		m_pP2->setSwitchConnected( m_pP1, connected );
	}
	
	if ( CircuitDocument * cd = m_pComponent->circuitDocument() )
		cd->requestAssignCircuits();
}


bool Switch::calculateCurrent()
{
	if ( !m_pP1 || !m_pP2 )
		return false;
	
	if ( state() == Open )
	{
		m_pP1->setSwitchCurrentKnown( this );
		m_pP2->setSwitchCurrentKnown( this );
		return true;
	}
	
	Pin * pins[2] = { m_pP1, m_pP2 };
	
	double current = 0.0;
	bool currentKnown = false;
	
	int pol;
	for ( unsigned i = 0; i < 2; ++i )
	{
		pol = (i == 0) ? 1 : -1;
		
		const WireList inputs = pins[i]->inputWireList();
		const WireList outputs = pins[i]->outputWireList();
		
		currentKnown = true;
		current = 0.0;
		
		WireList::const_iterator end = inputs.end();
		for ( WireList::const_iterator it = inputs.begin(); it != end; ++it )
		{
			if ( !(*it) )
				continue;
			
			if ( !(*it)->currentIsKnown() )
			{
				currentKnown = false;
				break;
			}
			
			current += (*it)->current();
		}
		
		if ( !currentKnown )
			continue;
		
		end = outputs.end();
		for ( WireList::const_iterator it = outputs.begin(); it != end; ++it )
		{
			if ( !(*it) )
				continue;
			
			if ( !(*it)->currentIsKnown() )
			{
				currentKnown = false;
				break;
			}
			
			current -= (*it)->current();
		}
		
		if ( currentKnown )
			break;
	}
	
	if ( !currentKnown )
		return false;
	
	m_pP1->setSwitchCurrentKnown( this );
	m_pP2->setSwitchCurrentKnown( this );
	m_pP1->mergeCurrent( -current * pol );
	m_pP2->mergeCurrent( current * pol );
	
	return true;
}

#include "switch.moc"