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Using the Residue Function as a Chip to Chip Synchronization Check

IP.com Disclosure Number: IPCOM000113204D
Original Publication Date: 1994-Jul-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 56K

Publishing Venue

IBM

Related People

Irish, JD: AUTHOR [+2]

Abstract

A method for detecting when chips get out of synchronization in a system containing multiple chips with the same part number that have sequencers that are required to be in lock step is disclosed. A residue-of-3 is generated by each chip over all of the synchronous sequencers and then compared with the value generated by all of the other chips.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Using the Residue Function as a Chip to Chip Synchronization Check

      A method for detecting when chips get out of synchronization in
a system containing multiple chips with the same part number that
have sequencers that are required to be in lock step is disclosed.  A
residue-of-3 is generated by each chip over all of the synchronous
sequencers and then compared with the value generated by all of the
other chips.

      The algorithm to be described involves a system containing
multiple chips with the same set of inputs and the same function.
One possible case is with cache/controller chips.  A cache structure
could be made up of two or more copies of the same chip where each
copy provides a portion of a whole word.  Although the copies all
have the same inputs, they may not always be doing the same thing.
In fact, it is quite probable that parts of the chips could be doing
different things.  But, there are likely to be parts of the chips
that always should be in lock step cycle by cycle.  The algorithm
described provides a method of detecting when one of these parts gets
out of step with the others.  This allows the system to be stopped
before too much damage is done.

      The detection algorithm uses a residue-of-three function in
each chip and includes in the residue function every sequencer or
register bit that is required to be in synchronization.  When all of
these signals are put through the residue function, log base two of n
signals are generated, where n...