Browse Prior Art Database

Dynamic Pin Skewing in Physical Modeling

IP.com Disclosure Number: IPCOM000034457D
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 [+2]

Abstract

Disclosed is a method for applying input stimuli to electronic devices being used as Physical Models for a logic or fault simulation. Physical modelers today have a timing resolution defined by the maximum pattern apply rate which typically ranges from 40 to 600 nanoseconds. Consequently, all net changes within this interval will be merged into one pattern. If the Physical Modeler does not have skew time capability, all nets changing in the interval are applied simultaneously to the device. Those Physical Modelers that have a skew time adjustment always have a fixed skew time.

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Dynamic Pin Skewing in Physical Modeling

Disclosed is a method for applying input stimuli to electronic devices being used as Physical Models for a logic or fault simulation. Physical modelers today have a timing resolution defined by the maximum pattern apply rate which typically ranges from 40 to 600 nanoseconds. Consequently, all net changes within this interval will be merged into one pattern. If the Physical Modeler does not have skew time capability, all nets changing in the interval are applied simultaneously to the device. Those Physical Modelers that have a skew time adjustment always have a fixed skew time. Since the simulation normally presents signal changes at varying times within the 40 to 600 nanosecond pattern interval, the fixed skews could mask timing errors and even change the sequence of signal input changes which could yield incorrect simulation results. Because of these problems, most simulators using Physical Modelers do not preserve an accurate simulation time to device real time correlation. This disclosure presents a method to dynamically skew pins to achieve high resolution timing accuracy with moderate pattern apply rates. A simulation signal input change time is converted into two values: a pattern number value, and a positive offset delay value. The latter enables each pin to individually skew its stimulate time within the typical 40 to 600 nanosecond pattern interval. For any pin, any pattern may change the skew time. This invention...