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Spring 2000
Computer Science 3410 - Lab Information
Design Entry using Truth Tables - Specifying the Timing
Pick a number that is easy to work with (5ns, 10ns, 20ns). This number is arbitrary, but it will become more significant later on. For now, I will use 20ns.
Select Options -> Grid Size. Type in 20ns.
Select File -> End Time. At this point it is very important to know how many valuations are possible with your set of inputs (For example, if you have n inputs, then you have a total of 2n possible valuations). For our function with two inputs, we have a total of 22 = 4 total valuations. The total End Time will thus be (20ns)(4) = 80ns.
Type this into the box and click OK.
Duplicating the truth table onto the waveform.
By pressing the icon in the top left corner (looks like two arrows pointing left and right), you can highlight any 20ns portion (a section) of an input and output by pressing and dragging the mouse pointer over the waveform for the input (or output). The waveform editor will then automatically change the present value from 0 to 1. Repeat this procedure for all inputs (and outputs).
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