AR# 1426: Orcad - Orcad VST: All outputs are undefined
Orcad - Orcad VST: All outputs are undefined
Keywords: VST, Orcad, undefined, simulation
General Description: A file such as "<design>.vst" loads without errors, but all outputs remain undefined. Trace and stimulus are defined correctly. Even if the global reset has been asserted, the flip-flop outputs are still undefined.
The simulator option Prefix 'G' needs to be used.
With VST 386+ versions 1.1 and older, the line:
PREFIX = 'G'
should be added to the VST configuration file (vst.cfg).
This can be done in three ways: 1. Running XDraft with version 1.1 should automatically add this line. 2. Edit the vst.cfg file and add the line: PREFIX = 'G' 3. From Orcad ESP, select Digital Simulation Tools -> Execute -> Simulate -> Configure Digital Simulation
Scroll down to the section that says "Prefix Options" and type ""G in one of the Prefix Definitions boxes.
The format of VST 386+ version 1.2 was changed so that all prefixes could be used except those that were specifically ignored.
Edit the vst.cfg file and look for the line: IPREFIX = 'G'
If you find this line, delete the G and save the file;
From Orcad ESP: Digital Simulation Tools -> Execute -> Simulate -> Configure Digital Simulation
Scroll down to the last section that says "Prefixes IGNORED by VST"