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- <title>Debugging subcircuits</title>
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- <h1>Debugging subcircuits</h1>
- <p>As you test larger circuits, you will likely find bugs. To nail down
- what's going wrong, exploring what's going on in the subcircuits while
- running the overall circuit can help. To enter the subcircuit's state, you can
- use any of three different techniques. The most straightforward is probably
- to view the simulation hierarchy by clicking the second icon in the explorer
- pane's upper toolbar (<img src="../../../../en/icons/projsim.gif" width="16" height="16">), or by selecting
- "View Simulation Tree" from the Project menu. This switches
- the explorer pane so that it shows the hierarchy of subcircuits being simulated.</p>
- <center><img src="../../../../en/img-guide/subcirc-hierarchy.png" width="393" height="285"></center>
- <p>Double-clicking an element in this hierarchy will display what is happening
- inside that subcircuit.</p>
- <p>The second way you can enter a subcircuit is to bring up its popup menu
- by right-clicking or control-clicking it, and then choosing the View option.</p>
- <center><img src="../../../../en/img-guide/subcirc-4-delve.png" width="393" height="285"></center>
- <p>And the third way is to first ensure the Poke Tool is selected
- and then click the subcircuit you want to enter;
- a magnifying glass will appear over the subcircuit's center, and
- double-clicking the magnifying glass will enter
- the subcircuit's state.</p>
- <p>In any case, once you enter the subcircuit, you'll see that the pins' values
- in the subcircuit match the values being sent through them from the containing
- circuit.</p>
- <center><img src="../../../../en/img-guide/subcirc-2-delve.png" width="393" height="285"></center>
- <p>While in the subcircuit, you are allowed to alter the circuit. If the
- changes affect any of the subcircuit's outputs, they are propagated into the
- containing circuit. One exception: The subcircuit inputs are determined based on
- the values coming into the circuit from the supercircuit, so it doesn't make
- sense to toggle those values. If you attempt to poke a subcircuit's input,
- a dialog will pop up asking, <q>The pin is tied to the supercircuit state.
- Create a new circuit state?</q> Clicking No will cancel the toggle request,
- while clicking Yes will create a copy of the viewed state,
- divorced from the outer circuit, with the input pin toggled.</p>
- <p>Once you have completed viewing and/or editing, you can return to the parent circuit
- either by double-clicking the parent circuit in the explorer pane, or via the Go Out
- To State submenu of the Simulate menu.</p>
- <p><strong>Next:</strong> <a href="library.html">Logisim libraries</a>.</p>
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