Remote Test Management for Digital Logic Circuits
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Solution Overview
Problem
Traditional Built-In Self-Test (BIST) methods for digital logic circuits are vulnerable to hardware Trojans due to the use of the same set of test patterns and expected signatures, which can lead to aliasing errors, allowing malicious modifications during manufacturing to go undetected.
Innovation Solution
Implementing a remote test management system that generates and transmits different test patterns and expected signatures for each test cycle, allowing for improved test coverage and detection of hardware faults, including malicious modifications, by using a remote test management device to manage and compare test signatures with expected signatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the same set of test patterns and expected signatures is used in traditional LBIST, then the test implementation is simple and deterministic, but the system becomes vulnerable to hardware Trojans and aliasing errors
Solution Approach 1:
The patent introduces a remote test management device as an intermediary between the test module and the test patterns/signatures. This mediator generates unique test patterns and expected signatures dynamically, preventing hardware Trojans from predicting test sequences while keeping the test module itself relatively simple. The remote device handles the complexity of pattern generation and management.
Solution Approach 2:
The system transitions from static, predetermined test patterns to dynamic, remotely-generated test patterns. The test patterns and expected signatures are no longer fixed but are generated on-demand by the remote test management device, making the system adaptive and unpredictable to potential hardware Trojans.
2Measurement precision
If remote test management is implemented to generate unique test patterns, then test coverage improves and aliasing errors are reduced, but communication overhead and system complexity increase
Solution Approach 1:
The system changes the parameters of test patterns dynamically through remote communication. Instead of transmitting complete test pattern sequences, the remote test management device transmits parameter sets (seed values, pattern generation algorithms) that allow the test module to generate patterns locally, reducing communication overhead while maintaining test uniqueness and accuracy.
3Ease of manufacture
If traditional LBIST with fixed test patterns is used, then the test implementation is straightforward, but hardware faults and malicious modifications may go undetected
Solution Approach 1:
The remote test management device prepares and transmits test parameters and expected signatures before the actual testing process. This preliminary action ensures that unique, tailored test patterns are ready for each testing session, improving fault detection capability while maintaining straightforward implementation through pre-computed test data.
Data Source
AI summary
Electronic devices (320) are provided which comprise a digital logic circuit (101) and a test module (322) adapted to receive test parameters from a remote test management device (310), generate test patterns based on the test parameters, apply the test patterns to the digital logic circuit, receive test responses from the digital logic circuit, compact the test responses into a test signature, and either transmit the test signature to the remote test management device or determine a test result based on a comparison of an expected signature received from the remote test management device with the test signature. Further provided are remote test management devices comprising means adapted to acquire test parameters suitable for generating test patterns for a digital logic circuit, acquire an expected signature corresponding to the test patterns, transmit the test parameters to at least one electronic device comprising the digital logic circuit, and either receive a test signature from the at least one electronic device and determine a test result based on a comparison of the expected signature with the test signature, or transmit the expected signature to the at least one electronic device.