Next: Step 2: Adding wires

Step 1: Adding gates

Recall that we're trying to build the following circuit in Logisim.

Building a circuit is easiest by inserting the gates first as a sort of skeleton for connecting wires into the circuit later. The first thing we're going to do is to add the two AND gates. Click on the AND tool in the toolbar (, the next-to-last tool listed). Then click in the editing area where you want the AND gates to go. Be sure to leave plenty of room for stuff on the left.

Notice the five dots on the left side of the AND gate. These are spots where wires can be attached. It happens that we'll just use two of them for our XOR circuit; but for other circuits, you may find that having more than two wires going to an AND gate is useful.

Now add the other gates. First click on the OR tool (); then click where you want it. And select the NOT tool () and put those two gates into the canvas.

I left a little space between the NOT gates and the AND gates; if you want to, though, you can put them up against each other and save yourself the effort of drawing a wire in later.

Now we want to add the two inputs x and y into the diagram. Select the input pin (), and place the pins down. You should also place an output pin () next to the OR gate's output. (Again, though I'm leaving a bit of space between the OR gate and the output pin, you might choose to place them right next to each other.)

If you decide you don't like where you placed something, then you can right-click (or control-click) anything in the canvas to view a pop-up menu. Choose Delete. You can also rearrange things using the select tool ().

Next: Step 2: Adding wires