Selective Memory Test Mode Enable via Command Sequencing

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Solution Overview

Problem

In multi-die memory boards, individual memory devices often contend with each other when receiving a test-mode enable command, making it difficult to test one device at a time due to common command reception.

Innovation Solution

A method is implemented where a common command is issued to multiple memory devices, with only the intended device being enabled into a test mode by determining the validity of prior commands and using a test-mode enable signal, ensuring only the valid command recipient enters the test mode.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a test-mode enable command is issued to all memory devices simultaneously, then all memory devices can be tested, but multiple devices contend with each other causing incorrect responses

Engineering Contradiction:

Improvetesting throughputVSAvoidtest response accuracy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent segments the testing process by dividing memory devices into groups and testing them sequentially rather than simultaneously. The system issues test-mode enable commands to different groups of memory devices at different times, preventing contention and ensuring accurate responses from each device during testing.

Inventive Principle:

Principle #1Segmentation

2Reliability

If individual memory devices are tested sequentially, then test response accuracy is improved, but testing time increases

Engineering Contradiction:

Improvetest response accuracyVSAvoidtesting duration

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent divides the memory devices into multiple groups that can be tested in parallel sequences. By segmenting the device population and implementing sequential testing within each group while maintaining parallel testing across multiple groups, the system achieves both accurate responses and reduced overall testing time.

Inventive Principle:

Principle #1Segmentation

3Ease of operation

If a common command is issued to all memory devices, then command transmission is simplified, but it becomes difficult to target specific devices for testing

Engineering Contradiction:

Improvecommand transmission simplicityVSAvoidcommand targeting precision

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent segments memory devices into distinct groups with unique identifiers or addresses. The system uses these segments to target specific groups for testing while maintaining a common command structure. This allows simplified command transmission while achieving precise device targeting through group-based addressing and selection mechanisms.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS7900099B2Enabling test modes of individual integrated circuit devices out of a plurality of integrated circuit devices

Publication Date: 2011.03.01 MICRON TECHNOLOGY INC

AI summary

Methods and apparatus are provided. A common test-mode enable signal is received at two or more integrated circuit devices of an electronic system. A test mode of only an integrated circuit device of the two or more integrated circuit devices that was last to receive a valid command is enabled in response to the common test-mode enable signal.