Memory Interface Timing Calibration via Eye Opening Edge Detection
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Solution Overview
Problem
Conventional memory interfaces face challenges in stable data reading and writing, especially at high speeds, due to increased jitter and physical limitations, making it difficult to determine whether data failures are from initial write or read issues, and requiring complex calibration processes.
Innovation Solution
A memory interface with delaying circuits, edge detecting circuits, and a control circuit that writes and reads test data to determine the phase of the data strobe signal, allowing for precise timing calibration by identifying the edges of the eye opening and adjusting delay values to ensure reliable data transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If timing calibration is performed using conventional methods with multiple test processes, then data transfer reliability can be improved, but device complexity and calibration time increase
Solution Approach 1:
The patent combines multiple calibration processes (write calibration and read calibration) into a single integrated calibration sequence. The control circuit performs both write and read operations using the same test pattern and delay adjustment mechanism, eliminating the need for separate calibration routines and reducing overall complexity while maintaining reliability
Solution Approach 2:
The delay adjustment circuit and control circuit are designed to perform multiple functions: they can adjust delays for both write operations and read operations, and can detect edges for both writing and reading test data. This multi-functional design reduces the number of separate calibration circuits needed and simplifies the overall system
2Measurement precision
If multiple test processes are performed to determine data failure causes, then measurement precision can be improved, but loss of time increases
Solution Approach 1:
The control circuit preliminarily adjusts the delay of the data strobe signal before performing read operations. By establishing the correct timing relationship in advance through write calibration, the subsequent read calibration process can proceed more quickly and with fewer iterations, reducing overall calibration time while maintaining precise failure detection
Solution Approach 2:
The calibration process uses continuous feedback from edge detection circuits to continuously adjust delays. The control circuit repeatedly writes test data, detects edges, adjusts delays, and re-reads data in a continuous loop until the correct timing is achieved, eliminating idle time between calibration steps and maintaining productive action throughout the process
3Adaptability or versatility
If frequency dividing ratio and clock mode are switched on the fly, then adaptability can be improved, but device complexity increases
Solution Approach 1:
The delay adjustment circuit dynamically adjusts the delay of the data strobe signal based on real-time edge detection feedback. Instead of requiring complex frequency switching, the system adapts to different timing conditions by continuously adjusting delays in a flexible manner, achieving adaptability without the complexity of multiple fixed clock modes
Data Source
AI summary
A memory interface includes a first delaying circuit configured to delay write data to be supplied to an input buffer; a second delaying circuit configured to delay read data read out from an output buffer; a data write circuit configured to supply said write data to a memory through said first delaying circuit; and a data read circuit configured to read said write data written in said memory, as said read data through said second delaying circuit. A control circuit is configured to detect positions of a start edge and end edge of an eye opening which is formed based on fluctuation of said write data or said read data, to specify an intermediate position of the start edge and the end edge, and to determine a phase of a data strobe signal based on a difference between the intermediate position and one of the start edge and the end edge.