The quick and dirty version of what this
does is as follows: We define a set of registers
and a wire that correspond to the inputs and
output of our device. The Test Bench is then
written to test each input iteration of en and a at
a 250 ns interval.
I’m sure your next question is, “How do we
see the results?” Another great question! With
Simulation view selected in ISE Design Suite,
select binary_decoder_test in the Behavioral
Hierarchy and double-click on Simulate
Behavioral Model in the Processes tree below.
The ISim software should open automatically.
Select the Simulation->Run All menu
38 July 2015
SCREENSHOT 4. ISim
PHOTO 2. Circuit test: EN = 1; A = 11;
and D = 1000.
PHOTO 3. Circuit test: EN = 0; A = 11;
and D = 0000.