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Browse Prior Art Database

Program Selectable Simultaneous Switch Limit

IP.com Disclosure Number: IPCOM000103307D
Original Publication Date: 1990-Sep-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 52K

Publishing Venue

IBM

Related People

Imming, KC: AUTHOR [+2]

Abstract

Disclosed is a hardware circuit which allows the number of off-chip drivers that are allowed to switch simultaneously on a VLSI chip to be changed under program control.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 70% of the total text.

Program Selectable Simultaneous Switch Limit

      Disclosed is a hardware circuit which allows the number of
off-chip drivers that are allowed to switch simultaneously on a VLSI
chip to be changed under program control.

      Many times when designing in state-of-the-art technologies,
design decisions must be made before the technology rules are
completely stable.  One of these technology rules is the number of
off-chip drivers that are allowed to switch simultaneously.  In the
past, a design decision was made based on early technology rules.
This method provides for program control of the number of
simultaneously switching drivers.

      A program controllable bit in the configuration register is
defined which controls the sequencing of data on the main system
buses.  Setting this bit on forces data on one of the buses to be
delayed until the chip is no longer driving data on the other bus.
Setting this bit off allows maximum performance by allowing both
system buses to be switched simultaneously.  By allowing this control
to be programmable (versus hardwired), the number of simultaneously
switching drivers can be set at any time. The design can be completed
independent of the technology rules for simultaneous switch.  Also, a
last minute change in the rules can be handled without redesigning
the hardware.

      Features of the Invention:
        1.  If the original technology did not allow simultaneous
switch, but a new technology does, th...