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Method for Testing the Memory Functional Path using Signature-based Memory Path Self-Test

IP.com Disclosure Number: IPCOM000019848D
Publication Date: 2003-Oct-01
Document File: 3 page(s) / 128K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for testing the memory functional path using signature-based memory path self-test. Benefits include improved functionality and improved performance.

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Method for Testing the Memory Functional Path using Signature-based Memory Path Self-Test

Disclosed is a method for testing the memory functional path using signature-based memory path self-test. Benefits include improved functionality and improved performance.

General description

         The disclosed method is testing the memory functional path using a signature-based (sig-based) memory path (MP) self-test. It detects design errors/bugs that pass the memory built-in self-test (BIST) and scan tests but fail functional tests. These design errors/bugs are very hard to isolate and fix. The disclosed method exercises the functional path and helps detect the problems easily.

         The disclosed method is used with custom-designed memory arrays, which have had careful attention paid to wire-length effects, cross-talk/noise, and voltage drops due to wire resistances. These designs are typically reused many times, increasing their robustness. In contrast, the paths to and from memory are synthesized and receive less attention regarding the contributing factors. Additionally, each synthesis run produces a different physical layout.

         The disclosed method can be used for testing caches as well as memory arrays.

         The key elements of the method include:

•         Tests through all ports and functional paths

•         Algorithms that exercise the functional path to enable maximum data transition between patterns

•         Cache tag functional test that is not covered by structured tests, such as memory BIST and scan-based tests

•         Multiple input shift register (MISR) for compressing data and generating the final signature

•         Comparison of the final signature and the prestored golden signature, exposing the bug or manufacturing defect

Advantages

         The disclosed method provides advantages, including:

•         Improved functionality due to including a cache tag function test that is not covered by structured tests, such as memory BIST and scan-based tests

•         Improved performance due to a shorter run-time with a similar speed as memory BIST

•         Improved cost effectiveness due to not requiring expensive testers

•         Improved cost effectiveness due to requiring minimal hardware overhead compared to memory BIST

Detailed description

         The disclosed method performs simple tests to ensure that the data path functionality related to memory writes and reads is correct. The method includes logic that tests Read/Write (R/W) control, the data pattern generator, and the address generator. Wherever possi...