Global Unichip Corporation

Jing-Reng Huang

Cheng-Wen Wu

Chih-Tsun Huang

Chi-Feng Wu

Chuang Cheng

A test pattern generation and comparison circuit creates test pattern stimulus signals for and evaluates response signals from logic or memory such as random access memory (RAM). It utilizes both parallel and serial interfaces to the logic/memory under test. The test pattern generation and comparison circuit further provides a method for testing logic and memory utilizing built-in self test (BIST) techniques. The method uses a programmable logic/memory commands which are translated into physical logic signals and timings for the logic or memory under test. The results of the test pattern generated and applied to the logic or memory are compared to expected results. The result of the comparison is a pass/fail designation. In addition, the comparison of the expected test results with the actual test results provides information on the exact location of the failure. Also, since the test pattern generation and comparison circuit architecture is compatible with hardware description languages such as Verilog HDL or VHDL, the test pattern generation and comparison circuit can be automatically generated with a silicon compiler.

Test pattern generator for SRAM and DRAM

In the present invention a built in self test (BIST) for an embedded memory is described. The BIST can be used at higher levels of assembly and for commodity memories to perform functional and AC memory tests. A BIST controller comprising a finite state machine is used to step through a test sequence and control a sequence controller. The sequence controller provides data and timing sequences to the embedded memory to provide page mode and non-page mode tests along with a refresh test. The BIST logic is scan tested prior to performing the built in self test and accommodations for normal memory refresh is made throughout the testing. The BIST also accommodates a burn-in test where unique burn-in test sequences can be applied.

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Hsinchu, Taiwan

Jing-Reng Huang