ELEC4200 Digital System Design Introduction to ISE & ModelSim (Lab0) Professor: Charles E. Stroud Tutorial by: Gefu Xu
	Schematic Capture 1) Now we create a blank sheet for schematic capture. First, click the Project and New Source menu. Click Schematic in the left frame and type in the name for your schematic. In this example, the file name of the schematic is Mux_Schematic but you can use any name you like. This schematic must be associated with our project, so make sure Add to project is selected before clicking Next. Also remember to set the location to a directory on the C: drive of the PC in the lab for maximum performance. This summary page is displayed and we can click Finish. 2) Now, we are ready to capture the schematic of the design. First, select Mux_Schematic.sch in Main Window and select Symbols in Sources Window. Then choose the desired component in the list of Symbols in Sources Window and drag-and-drop it onto the schematic sheet in main Window. Repeat the previous operations until all components are placed on the schematic. In this example, we will use two AND2s, one OR2 and one INV. Select the add wire icon and connect all components with wires. To add a wire, left click mouse on the start point (for example, the output of a gate) and then left click mouse on the next point you want the signal net to go (this could be the input to a gate or where you want the signal net to turn a corner) and continue this process until you have the signal net routed. To complete the signal net, double click mouse at the end point or hit ESC on the keyboard to release add wire mode.  Repeat this process until all signal nets have been routed. Select the add maker icon and add makers to all primary inputs and primary outputs. To add a maker, just left click mouse on the primary input/output point. To change the name of a marker to a descriptive input/output net name, double click mouse on the symbol of the maker and then change the name. In this example, the inputs are Din0, Din1, Sel and the output is Dout. Similarly, one can also change the name of any internal net by double clicking on the net and then changing the name. When the schematic is completed, click check schematic icon. In the Transcript Window, a message of No error or warning is detected will be reported if the schematic passes the check. Otherwise, you must fix each error until the schematic passes and then save your schematic.
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