Semiconductor Memory Command Signal Verification Feedback Loop
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Solution Overview
Problem
Errors in communication of command signals from a memory controller to a semiconductor memory device can lead to abnormal operations and poor performance due to inappropriate commands or noise corruption during transmission, necessitating effective verification methods.
Innovation Solution
The semiconductor memory device is equipped with a command decoder, mode setting portion, selecting signal generator, and selector to selectively output internal command signals for verification, allowing for the buffering and encoding of command signals, and enabling command test and memory cell test modes to ensure proper communication and operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If command signal testing is added to verify communication between memory controller and semiconductor memory device, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent implements a feedback mechanism where the semiconductor memory device outputs received command signals back to the memory controller for verification. The command signal testing unit captures the command signal from the memory controller, processes it through the command decoder, and then outputs the processed signal back through the selector to the memory controller, creating a closed-loop feedback system that enables reliability verification without requiring external testing equipment.
Solution Approach 2:
The command signal testing unit is designed to perform multiple functions: it can test command signal communication, verify data output accuracy, and operate in different test modes (command test mode and data test mode). This multi-functionality allows a single unit to address various reliability concerns, reducing the need for separate dedicated testing components and thereby limiting the increase in device complexity.
2Measurement precision
If command signal verification is implemented, then measurement precision of command signal transmission is improved, but device complexity increases
Solution Approach 1:
The feedback mechanism enables precise measurement of command signal transmission by capturing the original command signal from the memory controller, processing it through the same decoding path, and comparing the output with the original. This closed-loop feedback allows for accurate verification of signal integrity and transmission accuracy.
Solution Approach 2:
The command signal testing unit creates a copy of the command signal path for verification purposes. By duplicating the command signal processing path and using the selector to switch between normal operation and test mode, the system can measure and verify command signal transmission accuracy without interfering with normal device operation, thus achieving precise measurement with minimal added complexity.
3Productivity
If command signal testing functionality is added, then productivity of memory system operation is improved, but device complexity increases
Solution Approach 1:
The selector is designed to dynamically switch between different operational modes: normal data operation mode and command signal test mode. This dynamic switching capability allows the memory device to maintain high productivity during normal operations while enabling reliability verification during test modes, without permanently increasing the complexity of the device structure.
Solution Approach 2:
The command signal testing unit is integrated into the existing memory device structure and can perform multiple verification functions including command signal testing, data output verification, and mode switching. This multi-functionality allows the system to maintain high productivity by performing verification tasks during idle or low-activity periods without requiring separate dedicated testing hardware, thus improving overall system efficiency.
Data Source
AI summary
Embodiments of the invention include features in the semiconductor memory device that are configured to receive command signals from a memory controller and selectively output at least a portion of the received command signals back to the memory controller for verification. Embodiments of the invention also provide methods for verifying the proper communication of command signals from a memory controller to a semiconductor memory device. Embodiments of the invention also provide systems and methods for testing memory cells in a semiconductor memory device.