International Business Machines Corporation

Richard Bogholtz, Jr

Louis J Bosch

Kevin Charles Gower

Thomas G Mitchell

Thomas H Mitchell, Jr

A system for providing test data for testing a semiconductor memory includes generation means for successively developing generated data patterns beginning from a seed data pattern, such that every distinct data pattern of the seed data pattern is successively developed in a forward sequence and, subsequently, the distinct data patterns are successively developed in a reverse sequence relative to the forward sequence.

Memory testing system with algorithmic test data generation

A high speed tester stores the data corresponding to the first and last addresses of each test loop in a high speed cache. In the majority of test addresses, data is transferred from a memory into at least two shift registers and the cache is not accessed. The output of the shift registers are interleaved in a multiplexer to provide two bits of test data for each tester clock cycle. Control circuitry decodes bits associated with each data address and controls presenting data to the shift registers from the memory and the cache. Use of the cache allows a continuous output of test data from the multiplexer during repetitions of a loop and when new test loop are introduced, with no intervals in the data, regardless of whether the data terminates on an address boundary.

High speed tester

A tester of circuit devices is disclosed which uses commercially available component parts but is capable of high performance testing of hierarchical memory cards requiring data pulses of variable pulse widths at high repetition rates. The tester includes two memories connected to respective shift registers which in turn, feed a multiplexer. The memories handle test timing patterns for respective halves of the basic clock test cycle and are interleaved in operation along with the shift registers. Two opposite-phased outputs of the multiplexer are applied through respective programmable delay networks and pulse generators to the set and reset inputs of a trigger circuit. The trigger circuit provides test data to a dedicated input pin of the device under test.

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Mahopac, NY, United States of America

Richard Bogholtz, Jr