Browse Prior Art Database

Physical Modeling Initial and Final Value Definition for Pins

IP.com Disclosure Number: IPCOM000034446D
Original Publication Date: 1989-Feb-01
Included in the Prior Art Database: 2005-Jan-27
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Dubler, JF: AUTHOR [+3]

Abstract

Disclosed is a method of guaranteeing in an electronic design automation logic simulator/physical modeling system that the pins of a physical device are in a known state prior to each device computation and are left in a known state at the end of each device computation. Insuring that the pins are in a known state both at the beginning and at the end of each device computation eliminates the possibility of unpredictable or undesired results. Certain devices could produce unpredictable results when the initial values on the pins of a device are not in a known state prior to a device computation. The disclosed method defines a procedure for allowing the behavioral shell for a physical device to have an initial value defined for each pin of the device.

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Physical Modeling Initial and Final Value Definition for Pins

Disclosed is a method of guaranteeing in an electronic design automation logic simulator/physical modeling system that the pins of a physical device are in a known state prior to each device computation and are left in a known state at the end of each device computation. Insuring that the pins are in a known state both at the beginning and at the end of each device computation eliminates the possibility of unpredictable or undesired results. Certain devices could produce unpredictable results when the initial values on the pins of a device are not in a known state prior to a device computation. The disclosed method defines a procedure for allowing the behavioral shell for a physical device to have an initial value defined for each pin of the device. These initial values will be transmitted once to the physical modeler prior to the beginning of simulation. The initial value for each pin will be automatically applied to the device as the first pattern for each device computation. Therefore, each pin of the device will be in a known state prior to performing each device computation and the possibility of unpredictable results is eliminated. The initial value for each pin may take one of the following definitions: (1) ONE - The first value applied to the pin is a one.

(2) ZERO - The first value applied to the pin is a zero.

(3) H - The first value applied to the pin is a high impedance. Certain devices cou...