JTAG Test Controller Snapshot Restore for SSDs

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Solution Overview

Problem

Existing JTAG-based test controllers and debug tools cannot resume operations within a device under test (DUT) at the same processing code point where a snapshot was taken, due to the inability to capture and restore the full processing state, including data from peripheral components.

Innovation Solution

A test controller is developed that includes an interface to connect with a DUT and a processing system to receive an indication of a processing point, control the DUT to complete peripheral component tasks, save the task data, and transfer it to the test controller for subsequent resume processing operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional JTAG snapshot is taken, then the processing state can be captured, but the snapshot cannot be used to resume operations due to missing peripheral component data

Engineering Contradiction:

Improvesnapshot restore capabilityVSAvoidperipheral component task data

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The system performs preliminary actions by controlling the DUT to complete all peripheral component tasks and save their data to memory before the snapshot is taken. This ensures that when the snapshot is restored, the peripheral component data is already available in the memory, enabling successful resume operations without information loss.

Inventive Principle:

Principle #10Preliminary action

2Loss of information

If the DUT is controlled to complete peripheral tasks before snapshot, then full processing state is captured, but the testing process becomes more complex

Engineering Contradiction:

Improveprocessing state completenessVSAvoidtest controller operations

Core Design Contradiction:

Loss of informationVSDevice complexity

Solution Approach 1:

The DUT is configured to automatically complete its own peripheral component tasks and save the resulting data to its internal memory when instructed by the test controller. This self-service approach reduces the complexity of the test controller, as it only needs to initiate the process and retrieve the snapshot, rather than manually managing each peripheral component's data collection and storage.

Inventive Principle:

Principle #25Self-service

3Adaptability or versatility

If peripheral component data is saved in memory, then resume operation is enabled, but additional memory operations are required

Engineering Contradiction:

Improveresume processing capabilityVSAvoiddata saving operations

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system merges the peripheral component task completion, data saving to memory, and snapshot capture into a single integrated process. The test controller issues a single command to the DUT that triggers the completion of peripheral tasks, saves their data to memory, and captures the snapshot simultaneously, reducing the number of separate operations and simplifying the overall process.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS12205660B2Test controller enabling a snapshot restore and resume operation within a device under test

Publication Date: 2025.01.21 SANDISK TECHNOLOGIES LLC

AI summary

Techniques are provided for capturing a processing state snapshot of a device under test (DUT) that enable a previous test run to be restored and resumed from the same point the snapshot was taken. The techniques enable restoring the snapshot into the same or a different device to resume a previous test run. In an illustrative example, a DUT is controlled by a Joint Test Action Group (JTAG) test controller to capture a Steady State Snapshot by controlling peripheral components of the DUT to complete any on-going tasks to reach a steady state and then flush data to a memory of the DUT. The flushed steady state peripheral component data and other processing state data is transferred to the test controller for analysis and for enabling the subsequent restore and resume operation. Solid state drive (SSD) examples are provided.