VCOElm.java

/*    
    Copyright (C) Paul Falstad and Iain Sharp
    
    This file is part of CircuitJS1.

    CircuitJS1 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.

    CircuitJS1 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 CircuitJS1.  If not, see <http://www.gnu.org/licenses/>.
*/

package com.lushprojects.circuitjs1.client;

//import java.awt.*;
//import java.util.StringTokenizer;

    class VCOElm extends ChipElm {
	public VCOElm(int xx, int yy) { super(xx, yy); }
	public VCOElm(int xa, int ya, int xb, int yb, int f,
		      StringTokenizer st) {
	    super(xa, ya, xb, yb, f, st);
	}
	String getChipName() { return "VCO"; }
	void setupPins() {
	    sizeX = 2;
	    sizeY = 4;
	    pins = new Pin[6];
	    pins[0] = new Pin(0, SIDE_W, "Vi");
	    pins[1] = new Pin(3, SIDE_W, "Vo");
	    pins[1].output = true;
	    pins[2] = new Pin(0, SIDE_E, "C");
	    pins[3] = new Pin(1, SIDE_E, "C");
	    pins[4] = new Pin(2, SIDE_E, "R1");
	    pins[4].output = true;
	    pins[5] = new Pin(3, SIDE_E, "R2");
	    pins[5].output = true;
	}
	boolean nonLinear() { return true; }
	void stamp() {
	    // output pin
	    sim.stampVoltageSource(0, nodes[1], pins[1].voltSource);
	    // attach Vi to R1 pin so its current is proportional to Vi
	    sim.stampVoltageSource(nodes[0], nodes[4], pins[4].voltSource, 0);
	    // attach 5V to R2 pin so we get a current going
	    sim.stampVoltageSource(0, nodes[5], pins[5].voltSource, 5);
	    // put resistor across cap pins to give current somewhere to go
	    // in case cap is not connected
	    sim.stampResistor(nodes[2], nodes[3], cResistance);
	    sim.stampNonLinear(nodes[2]);
	    sim.stampNonLinear(nodes[3]);
	}
	final double cResistance = 1e6;
	double cCurrent;
	int cDir;
	void doStep() {
	    double vc = volts[3]-volts[2];
	    double vo = volts[1];
	    int dir = (vo < 2.5) ? 1 : -1;
	    // switch direction of current through cap as we oscillate
	    if (vo < 2.5 && vc > 4.5) {
		vo = 5;
		dir = -1;
	    }
	    if (vo > 2.5 && vc < .5) {
		vo = 0;
		dir = 1;
	    }

	    // generate output voltage
	    sim.updateVoltageSource(0, nodes[1], pins[1].voltSource, vo);
	    // now we set the current through the cap to be equal to the
	    // current through R1 and R2, so we can measure the voltage
	    // across the cap
	    int cur1 = sim.nodeList.size() + pins[4].voltSource;
	    int cur2 = sim.nodeList.size() + pins[5].voltSource;
	    sim.stampMatrix(nodes[2], cur1, dir);
	    sim.stampMatrix(nodes[2], cur2, dir);
	    sim.stampMatrix(nodes[3], cur1, -dir);
	    sim.stampMatrix(nodes[3], cur2, -dir);
	    cDir = dir;
	}
	// can't do this in calculateCurrent() because it's called before
        // we get pins[4].current and pins[5].current, which we need
	void computeCurrent() {
	    if (cResistance == 0)
		return;
	    double c = cDir*(pins[4].current + pins[5].current) +
		(volts[3]-volts[2])/cResistance;
	    pins[2].current = -c;
	    pins[3].current = c;
	    pins[0].current = -pins[4].current;
	}
	void draw(Graphics g) {
	    computeCurrent();
	    drawChip(g);
	}
	int getPostCount() { return 6; }
	int getVoltageSourceCount() { return 3; }
	int getDumpType() { return 158; }
    }