Non-destructive Memory Testing via Data Converter
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Solution Overview
Problem
Current memory testing during mission mode self-test (MMST) is destructive, leading to data loss and increased overhead due to the need to save and restore partition data, which affects test efficiency and resource utilization.
Innovation Solution
An MBIST diagnostics system that includes a converter to process functional data without altering it, allowing for non-destructive testing by generating outputs corresponding to both original and converted data, utilizing a test access method, algorithm memory unit, sequence iterator, data compare unit, and error correction logic to efficiently test memories without data loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If MBIST is used to test memories during MMST, then memory testing capability is improved, but functional data is destroyed
Solution Approach 1:
The memory system is divided into multiple banks, allowing selective testing of specific banks while others remain operational and preserve their data. The MBIST controller can isolate and test individual memory banks without affecting the functional data in other banks, thus resolving the contradiction between testing capability and data preservation.
Solution Approach 2:
A converter component is introduced as an intermediary between the MBIST controller and the memory banks. This converter translates and controls the interaction, enabling testing operations while protecting the functional data through controlled data flow and conversion processes.
2Reliability
If partition data is saved and restored during MMST, then memory testing can occur, but test overhead increases
Solution Approach 1:
By segmenting the memory into multiple banks and enabling selective testing, the system avoids the need to save and restore entire partition data. Only the specific bank being tested is isolated, while other banks continue operational, eliminating the time-consuming save/restore overhead.
Solution Approach 2:
The system performs preliminary configuration of the MBIST controller and converter before testing begins, setting up the test environment in advance. This preliminary setup eliminates the need for repeated data saving and restoring operations during actual testing, reducing overall overhead.
3Reliability
If partition data is saved and restored during MMST, then memory testing can occur, but chip area resources increase
Solution Approach 1:
The MBIST controller and converter are designed as multi-functional components that can operate in multiple modes (testing mode and normal operation mode). This universality eliminates the need for separate dedicated testing hardware that would consume additional chip area, as the same components serve both testing and functional purposes.
Solution Approach 2:
The testing functionality is merged with the existing memory bank structure and control logic. By integrating MBIST controller and converter within the existing memory architecture rather than adding separate testing subsystems, the chip area overhead is minimized while maintaining full testing capability.
Data Source
AI summary
Systems and methods disclosed herein provide for efficiently testing memories during mission mode self-test (“MMST”) without destroying any original functional data. Embodiments provide for a converter to feed a manipulated version of the original functional data back into the tested memories. Embodiments further provide an accumulator to count the occurrences of correctable and uncorrectable errors associated with the tested memories.