Browse Prior Art Database

Gate Level Self-Test for Field-Replaceable Unit

IP.com Disclosure Number: IPCOM000060426D
Original Publication Date: 1986-Apr-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Diehl, CM: AUTHOR [+2]

Abstract

Each gate in a system design has a socket that is wired to accommodate a self-test field-replaceable unit (STF). The STF contains a linear feedback shift register (LFSR) that generates pseudo-random patterns, a multi-input shift register (MISR) for signature compression, compare circuitry, a read-only memory (ROM) containing the final signatures of each field-replaceable unit (FRU) in the gate, and clock/control circuitry for self-test. When the STF 1 is plugged into the gate, and activated, each partition in the gate is fed the appropriate clock signals via the STF clock/control 2 and pseudo-random patterns from the LFSR 3. The output of each level sensitive scan design (LSSD) scan string in the partition will be fed back into the MISR 4.

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Gate Level Self-Test for Field-Replaceable Unit

Each gate in a system design has a socket that is wired to accommodate a self- test field-replaceable unit (STF). The STF contains a linear feedback shift register (LFSR) that generates pseudo-random patterns, a multi-input shift register (MISR) for signature compression, compare circuitry, a read-only memory (ROM) containing the final signatures of each field-replaceable unit (FRU) in the gate, and clock/control circuitry for self-test. When the STF 1 is plugged into the gate, and activated, each partition in the gate is fed the appropriate clock signals via the STF clock/control 2 and pseudo-random patterns from the LFSR 3. The output of each level sensitive scan design (LSSD) scan string in the partition will be fed back into the MISR 4. The signature in the MISR 4 is compared to the predetermined good signature that is stored in the ROM 5 for each partition in that gate. A mis-compare will stop the test and the partition in error will be indicated with its associated FRU(s) 6.

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