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Browse Prior Art Database

Method for Simulating Special Bus Scenarios

IP.com Disclosure Number: IPCOM000112306D
Original Publication Date: 1994-Apr-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 51K

Publishing Venue

IBM

Related People

Harris, GD: AUTHOR [+2]

Abstract

Disclosed is a method for simulating special bus scenarios that generic bus behaviorals are not typically capable of producing. Usually, these scenarios are tested by specific test cases, so it is not necessary for the general behavioral to be able to produce them. However, the test case writer needs an easy way to generate the individual tests.

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Method for Simulating Special Bus Scenarios

      Disclosed is a method for simulating special bus scenarios that
generic bus behaviorals are not typically capable of producing.
Usually, these scenarios are tested by specific test cases, so it is
not necessary for the general behavioral to be able to produce them.
However, the test case writer needs an easy way to generate the
individual tests.

      Typical bus behaviorals provide normal bus transfers without
much difficulty.  However, most busses have special scenarios that
the bus behavioral is not able to produce.  For example, a bus can
have master termination without transfer, and bus to bus transfers.
These MUST be tested to ensure a quality system.  The "Choker" was
invented to provide this test capability.

      The biggest problem that test case writers have is driving a
zero onto a signal that the behavioral is driving to a one.  The
simulator does not support this.  Therefore, if a device (i.e. the
bus behavioral) is driving the wrong state onto a line and that state
is a one, the test of interest cannot be created.  The Choker's
function is to "choke" off the wrong value, substituting the
user-supplied value.  This choking function can be used to mask
signals going in either direction:  to the bus behavioral or the bus
controller.  The Choker is implemented using two muxes:  One mux
accepts bus behavioral outputs and dummy signals, which are selected
using a group of select lines.  This...