0.1 A quartus project from start to finish: 2 bit mux tutorial  (Page 3/4)

• The final step will be to connect all our components together. As previously mentioned, we can run wires directly between components or make wireless connections.
• To make a wired connection, either select the orthogonal node tool or move your mouse over one of the ports on a symbol, the pointer should change to the look like the node tool. Then click and drag from the origin port to the port you wish to reach and release. Be careful not to intersect any other ports as this will cause them to be joined to the wire, although crossing over other wires will not create a connection. You can tell if a wire is connected to something by the large dot, the typical indicator of connections in circuit diagrams. Go ahead and connect up the inputs to the two AND gates so that they will function as the beginning of a MUX.

• While this method is fairly straightforward, it has its disadvantages such as possible unintended connections and vast webs of wiring on more complicated circuits. We can simplify the process with wireless connections.
• Unfortunately, you cannot directly name ports. Instead we will connect a small piece of wire to the ports and name this wire. Any wires on the grid which share the same name are connected together.
• Begin by placing short bits of wire at all the remaining ports in the circuit. A length of one on the grid is sufficient though a length of two may be easier to work with. Once placed, right click on the wire and select properties.
• Under the General tab you can enter a name for the selected wire. As with project names, Quartus won’t allow for spaces so either remove them or use underscores. To connect any other wire with this named one, simply repeat the procedure. Using this wireless method, connect the remainder of the MUX together.

• The final step before we get to pin connections is to make sure our circuit is functional. On the left side of the screen is the Tasks menu where we can find a variety of commands to create a finished design file. Eventually we will want to compile our whole design, though for now we can simply go through the Anaylsis&Synthesis step. Double click on Analysis&Synthesis for Quartus to check over the circuit for any potential issues such as unconnected ports. If Quartus finds something wrong it will halt the process and display the error in the message box at the bottom of the screen.

Defining i/o connections

• Once we’ve successfully performed Analysis&Synthesis we are ready to move on to defining pin connections. In order to do this we first need to know the pin addresses of the input and output devices on our DE0 board. These can be found in the DE0 User Manual on pages 24-29, pages 27-32 of the PDF. For now we will only be looking at the switch and LED pin assignments.
• For each entry in the assignment table, the signal name corresponds to the identifier printed on the board next to the relavent device and the pin name tells us where we should connect to in order to access that device.
• To specify these connections we will use the Pin Planner located under Assignments->Pin Planner. By performing Analysis and Synthesis earlier, we gave Quartus information on how many I/O pins we had on our circuit diagram and what their names were. Now we just need to connect these with pins on the board. By putting in the name of a physical pin under the Location column in the Pin Planner, we tie that point on our board to the specified point on our circuit.
• Although we’ll be using a particular pin layout here, you can setup your pin assignments in whatever way you feel works best for you. On future labs/projects pin layouts will already be setup so the labbies and in particular the project graders will be expecting a particular board setup and you should leave assignments as they are.
• For this example we’ll use the rightmost slider switch, SW[0], for our select signal. Since we can see in the user manual that SW[0]is tied to PIN_J6, we simply type this, or even just J6 and it will fill in the name, into the Location column next to the “select” listing under the Node Name column. We’ll continue in this fashion, assigning “data1” to SW[1] at PIN_H5, “data2” to SW[2]at PN_H6, and assigning “out” to the rightmost LED, LEDG[0] at PIN_J1.