Browse Prior Art Database

Identification of VLSI Devices Using Signature Registers

IP.com Disclosure Number: IPCOM000120511D
Original Publication Date: 1991-May-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 2 page(s) / 71K

Publishing Venue

IBM

Related People

Hajdu, J: AUTHOR [+3]

Abstract

For identifying VLSI devices of higher level packages, for example, in the system environment, different part numbers and hardware engineering levels frequently have to be known for system configuration. Another application is the identification of configurable systems by the addition of option cards and units (uniprocessor, multiprocessor, etc.).

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Identification of VLSI Devices Using Signature Registers

      For identifying VLSI devices of higher level packages,
for example, in the system environment, different part numbers and
hardware engineering levels frequently have to be known for system
configuration.  Another application is the identification of
configurable systems by the addition of option cards and units
(uniprocessor, multiprocessor, etc.).

      Usually, the described problem is solved by a diode matrix
which forms part of each functional unit to be identified and sensed
for identification.  Another known solution is based on a chip
internal register which is added to the normal functional logic of
each chip.  The identification register is a shift register which can
be loaded by the bit string of a chip to be identified
(identification code) and which then responds with an identification
signal.

      For signature testing, the signature register, which is
implemented as part of each chip anyway, is able to fulfill that task
with less hardware overhead than is needed for an extra
identification register (or a diode matrix).  The hardware overhead
is zero, if the "known good" signature is hardwired on the device to
be identified and very small (about 6 to 8 gates), if only the
signature register without this additional feature is implemented.

      In signature testing, the test responses of a device under test
are compressed into a codeword, called signature, by a linear
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