Solutions Database

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Foundation Simulator: simulating bidirectional signals

Record #1286

Product Family:  Software

Product Line:  Aldec

Problem Title:
Foundation Simulator:  simulating bidirectional signals


Problem Description:
How do I setup simulation stimulus so that I can properly simulate
a bidirectional pin?


Solution 1:

Use the 'Chip Controlled' (CC) mode when simulating
bidirectional signals.	This will allow a chip (symbol) output
to override the test vector.

For example:

You are simulating a bidirectional pin BIDIR, and have applied
a stimulator to BIDIR.	You want this stimulus to appear on BIDIR when the 3-sta
te buffer is disabled.

Now, when the 3-state buffer is enabled, you want to view its
output on BIDIR, but the input test vector is overriding
the output.

Using CC mode on the BIDIR stimulator will allow the output of
the 3-state buffer to override the stimulus.

To apply the CC mode to a stimulator, select the signal in the
Waveform Viewer, and either click on the CC button in the
Stimulator Selection Window, or select Stimulator->Chip
Controlled Mode.

Stimulators that are in 'Override' (OV) mode are displayed
in red in the Waveform Viewer.	Stimulators that are in CC mode
are displayed in black.



End of Record #1286