International Business Machines Corporation

Peter O Jakobsen

Michael Richard Ouellette

Darren Lane Anand

Donald Lawrence Wheater

Steven Frederick Oakland

John Robert Goss

Pamela Sue Gillis

William R Tonti

John Atkinson Fifield

John Edward Barth, Jr

David E Lackey

Jeffrey H Dreibelbis

Krishnendu Mondal

Douglas Wayne Kemerer

Thomas Gregory Sopchak

Thomas E Obremski

Bruce Cowan

L Owen Farnsworth, Iii

Thomas O Sopchak

The invention provides a circuit that can observe data within shift registers without altering the data. The circuit includes selectors connected to the inputs and outputs of the shift registers. The selectors selectively connect the input with the output of a selected shift register to form a wiring loop for the selected shift register. A control device connected to the wiring loop uses the wiring loop to cause the data to be continually transferred from the output of the selected shift register to the input of the selected shift register and back through the selected shift register in a circular manner. The control device includes a counter used for determining the length of a selected shift register and a set of registers to store, for future use when rotating data in the shift registers, the length of each shift register. The control device also includes a data output accessible from outside the circuit. An observation wire is connected to the wiring loop, and the data passes from the wiring loop to the control device through the observation wire. The control device outputs data appearing on the wiring loop as the data is circulated through the selected shift register to permit data within the selected shift register to be observed outside the circuit without altering the data within the selected shift register.

Diagnostic method and apparatus for non-destructively observing latch data

A chip repair system designed for automated test equipment independent application on many unique very dense ASIC devices in a high turnover environment is disclosed. During test, the system will control on chip built-in self-test (BIST) engines collect and compress repair data, program fuses and finally decompress and reload the repair data for post fuse testing. In end use application this system decompresses and loads the repair data at power-up or at the request of the system.

Method of electrically blowing fuses under control of an on-chip tester interface apparatus

A method and apparatus for initializing an integrated circuit using compressed data from a remote fusebox allows a reduction in the number of fuses required to repair or customize an integrated circuit and allows fuses to be grouped outside of the macros repaired by the fuses. The remote location of fuses allows flexibility in the placement of macros having redundant repair capability, as well as a preferable grouping of fuses for both programming convenience and circuit layout facilitation. The fuses are arranged in rows and columns and represent control words and run-length compressed data to provide a greater quantity of repair points per fuse. The data can be loaded serially into shift registers and shifted to the macro locations to control the selection of redundant circuits to repair integrated circuits having defects or to customize logic.

Method and apparatus for initializing an integrated circuit using compressed data from a remote fusebox

A programmable data generator for generating input test data to be applied to a semiconductor memory array is disclosed. In an exemplary embodiment of the invention, the data generator includes a programmable address scramble register which has a plurality of storage locations associated therewith. The plurality of storage locations corresponds to array address bits associated with an address generator. A first exclusive OR (XOR) logic structure is coupled to the address generator and the address scramble register, wherein the first XOR logic structure generates an address-dependent, data scramble output signal that ultimately determines a data pattern to be applied to the memory array.

Programmable built-in self test (BIST) data generator for semiconductor memory devices

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Milton, VT, United States of America

Peter O Jakobsen