code: /**
   * Copyright (c) 2004-2005, Regents of the University of California
   * 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 University of California, Los Angeles 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 THE COPYRIGHT
   * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  package avrora.sim.platform;
  
  import avrora.sim.FiniteStateMachine;
  import avrora.sim.Simulator;
  import avrora.sim.output.SimPrinter;
  import avrora.sim.clock.Clock;
  import avrora.sim.mcu.ATMegaFamily;
  import avrora.sim.mcu.Microcontroller;
  import cck.text.Terminal;
  
  
  /**
   * The <code>PinWire</code> class is the interface for making wire connections
   * to other microcontrollers.
   *
   * @author Jacob Everist
   */
  
  public class PinWire {
  
      protected Simulator sim;
  
      protected final FiniteStateMachine state;
  
      protected final int colorNum;
      protected final String pinName;
  
      protected final ATMegaFamily atmel;
  
      // names of the states of this device
      private static final String[] modeName = {"low", "high"};
  
      // default mode of the device is off
      private static final int startMode = 0;
  
      // whether the microcontroller can read this as input
      private boolean acceptsInput;
  
      // whether the microcontroller can write this as output
      private boolean acceptsOutput;
  
      // input/output connectors
      public WireInput wireInput;
      public WireOutput wireOutput;
  
      // probe of the PinWire activity
      protected final PinWireProbe probe;
  
      // propagation delay in cycles
      protected final long propDelay;
  
      protected PinWire(Simulator s, int colorNum, String pinName) {
  
          sim = s;
          Clock clock = sim.getClock();
          state = new FiniteStateMachine(clock, startMode, modeName, 0);
          wireOutput = new WireOutput();
          wireInput = new WireInput();
  
          acceptsInput = false;
          acceptsOutput = false;
  
          probe = new PinWireProbe();
  
          this.colorNum = colorNum;
          this.pinName = pinName;
          atmel = null;
  
          propDelay = clock.millisToCycles(0.0014);
  
      }
  
      protected PinWire(Simulator s, int colorNum, String pinName, Microcontroller mcu) {
  
          sim = s;
          Clock clock = sim.getClock();
          state = new FiniteStateMachine(clock, startMode, modeName, 0);
          wireOutput = new WireOutput();
          wireInput = new WireInput();
  
          acceptsInput = false;
          acceptsOutput = false;
  
          probe = new PinWireProbe();
  
          this.colorNum = colorNum;
          this.pinName = pinName;
          atmel = (ATMegaFamily) mcu;
          propDelay = clock.millisToCycles(0.0014);
      }
  
      public String readName() {
          return pinName;
      }
  
      public void enableConnect() {
          state.insertProbe(probe);
      }
  
      public void disableConnect() {
          state.removeProbe(probe);
      }
  
      public boolean inputReady() {
          return acceptsInput;
      }
  
      public boolean outputReady() {
          return acceptsOutput;
      }
  
      /**
       * The <code>PinWireProbe</code> class implements a probe from the (tiny) finite state machine
       * that represents an PinWire's state. An PinWire can be "off" or "on". This probe will simply
       * display changes to the state.
       */
      class PinWireProbe implements FiniteStateMachine.Probe {
          final SimPrinter printer;
  
          PinWireProbe() {
              printer = sim.getPrinter();
          }
  
          public void fireBeforeTransition(int beforeState, int afterState) {
              // do nothing
          }
  
          public void fireAfterTransition(int beforeState, int afterState) {
              if (beforeState == afterState) return;
  
              // print the status of the PinWire
              StringBuffer buf = printer.getBuffer(20);
              Terminal.append(colorNum, buf, pinName);
              buf.append(": ");
              buf.append(modeName[afterState]);
              printer.printBuffer(buf);
              
              wireInput.onStateChange(afterState == 1);
          }
      }
  
      class WireInput extends Microcontroller.Pin.ListenableInput {
  
          /**
           * Constructor
           */
          protected WireInput() { }
  
          /**
           * The <code>enableInput()</code> method is called by the simulator when the program changes the
           * direction of the pin. The device connected to this pin can then take action accordingly.
           */
          public void enableInput() {
              acceptsInput = true;
  
              // automatically disable output
              acceptsOutput = false;
          }
  
          /**
           * The <code>read()</code> method is called by the simulator when the program attempts to read the
           * level of the pin. The device can then compute and return the current level of the pin.
           *
           * @return true if the level of the pin is high; false otherwise
           */
          public boolean read() {
              // read the current state and return boolean value
              return state.getCurrentState() == 1;
          }
          
          /**
           * Called when the state of the pinwire has changed
           */
          public void onStateChange(boolean newState) {
              notifyListeners(newState);
          }
      }
  
      class WireOutput implements Microcontroller.Pin.Output {
  
          /**
           * Constructor
           */
          protected WireOutput() {
          }
  
          /**
           * The <code>enableOutput()</code> method is called by the simulator when the program changes the
           * direction of the pin. The device connected to this pin can then take action accordingly.
           */
          public void enableOutput() {
              acceptsOutput = true;
  
              // automatically disable input
              acceptsInput = false;
          }
  
          /**
           * The <code>write()</code> method is called by the simulator when the program writes a logical
           * level to the pin. The device can then take the appropriate action.
           *
           * @param level a boolean representing the logical level of the write
           */
          public void write(boolean level) {
  
              // propagate signal after 1.4 uS =
              //sim.insertEvent(new WirePropagationEvent(level), propDelay);
  
  
              if (level)
                  state.transition(1);
              else
                  state.transition(0);
  
          }
  
          protected class WirePropagationEvent implements Simulator.Event {
              private boolean value;
  
              public WirePropagationEvent(boolean value) {
                  this.value = value;
              }
  
              // propagate signal to the pin finally
              public void fire() {
                  if (value)
                      state.transition(1);
                  else
                      state.transition(0);
              }
          }
  
      }
  
  }
  