PCIe Board Programmable LTSSM for Corner-Case Coverage

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Solution Overview

Problem

Current analyzer devices are unable to test all corner cases covered by the PCI Express Link Training and Status State Machine (LTSSM) due to their inability to handle states other than predetermined ones, limiting comprehensive testing of PCI boards.

Innovation Solution

A device is provided that generates a programmable LTSSM test configuration, allowing for tracing through different states and paths, receiving results, and modifying the configuration based on those results to include additional states, thereby enabling testing of unexpected conditions and corner cases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a predetermined LTSSM configuration is used for testing, then the device operation is simple, but the testing coverage is limited and cannot handle corner cases

Engineering Contradiction:

Improvetesting coverageVSAvoidanalyzer device complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The LTSSM configuration is made dynamic and programmable, allowing the state machine to be reconfigured during testing to handle different corner cases and unexpected conditions, rather than being fixed to predetermined states only

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The analyzer device allows modification of LTSSM configuration parameters including states, transitions, and timing values to adapt testing to various corner cases and unexpected conditions encountered during test execution

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If the LTSSM configuration is made programmable to handle unexpected conditions, then the testing capability is improved, but the device complexity increases

Engineering Contradiction:

Improvecorner case handling capabilityVSAvoidanalyzer device structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The analyzer device is designed with universal programmable capabilities that can handle multiple testing scenarios and corner cases through a single configurable LTSSM engine, rather than requiring separate dedicated circuits for each test case

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses feedback from test results to dynamically modify the LTSSM configuration, allowing the device to adapt to unexpected conditions and corner cases by learning from previous test outcomes and adjusting its behavior accordingly

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS12360871B2Peripheral component interconnect board programmable link training and status state machine and state branching

Publication Date: 2025.07.15 VIAVI SOLUTIONS INC(US)

AI summary

A device may generate a link training and status state machine (LTSSM) test configuration that includes states and paths connecting the states, and may provide the LTSSM test configuration for tracing through by a device under test. The device may receive results associated with tracing through of the LTSSM test configuration by the device under test, and may modify, based on the results, one of the paths of the LTSSM test configuration to include a different one of the states and to generate a modified LTSSM test configuration. The device may provide the modified LTSSM test configuration for tracing through by the device under test.