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A scientific study of the problems of digital engineering for space flight systems,
with a view to their practical solution.


Forcing Signal Errors with VHDL

Ben Cohen
VhdlCohen Publishing
http://www.vhdlcohen.com/
vhdlcohen@aol.com
January 3, 2001

Abstract

This paper presents a technique, which uses the user-defined resolution function feature of VHDL, to selectively control from VHDL the assertion of errors imposed on testbench signals of type Std_Logic. This technique allows the testbench environment to selectively inject errors at specific times and with specific values onto signals to verify the design-under-test responses to interface errors.

Table of Contents

1. Introduction
2. Use of User-Defined Resolution Function

2.1 Method of Operation
2.2 Application Example

List of Figures

Figure 1. Incorrectly Attempting to Force a Value onto a Bus

Figure 2. Forcing a Value onto a Bus with Resolved Record Type

Figure 2.2-1. Test Component

Figure 2.2-2. Testbench with Error Injection

Figure 2.2-3. Simulation Results


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