Source-Synchronous Strobe Gating for Skew-Tolerant Data Transfer

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Solution Overview

Problem

High-speed data transfer in source-synchronous communication is hindered by board skews and delay variations, making it challenging to maintain synchronous transfer with a single central clock, and conventional strobe gating techniques are inadequate in handling tri-state conditions and high-frequency variations.

Innovation Solution

The proposed solution involves improved timing control of strobe signals through advanced enable pulse shifting and ungating techniques, including the use of configuration bits and bypass circuits to extend timing windows and account for temperature and voltage variations, allowing for precise gating and ungating of non-free-running strobes to prevent glitches and ensure reliable data capture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single central clock is used for synchronous transfer, then timing synchronization is simplified, but board skew and delay variation make reliable transfer difficult

Engineering Contradiction:
Improveclock synchronization complexityVSAvoidsynchronous transfer reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent divides the data bus into small groups of bits, each with its own associated clock or strobe signal. This segmentation allows each group to be transferred independently with its own timing reference, compensating for board skew and delay variations that would affect a single centralized clock approach.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the timing parameters by associating each data group with its own clock/strobe signal rather than using a single central clock. This parameter change enables the system to adapt to varying delay conditions across different signal paths, improving transfer reliability despite board skew.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If strobe gating is used to control data transfer, then timing control is improved, but conventional techniques are inadequate for tri-state conditions and high-frequency variations

Engineering Contradiction:
Improvetiming control precisionVSAvoidstrobe gating reliability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies preliminary action by extending timing windows and preparing enable pulses in advance to account for temperature and voltage variations. This allows the strobe gating to be properly timed before actual data transfer, preventing glitches and ensuring reliable capture even under varying conditions.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces dynamic adjustment capabilities through bypass circuits and configuration bits that allow timing parameters to be adapted in real-time. This dynamic approach enables the system to handle high-frequency variations and tri-state conditions by adjusting timing windows as needed.

Inventive Principle:
Principle #15Dynamics

3Reliability

If timing windows are extended to account for variations, then reliability under varying conditions improves, but switch-over 'dead' time increases

Engineering Contradiction:
Improveoperation reliability under variationsVSAvoidswitch-over dead time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent uses configuration bits to dynamically adjust timing parameters, allowing the system to optimize between extended timing windows for reliability and minimized dead time for efficiency. By changing timing parameters based on operational conditions, the system achieves both goals in different scenarios.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2577667B1Apparatus for source-synchronous information transfer and associated methods
Publication Date: 2019.06.26 ALTERA CORP
  • EP2577667B1 patent drawingFigure 1~4
  • EP2577667B1 patent drawingFigure 2~5
  • EP2577667B1 patent drawingFigure 3

AI summary

An apparatus includes an interface circuit coupled to an electronic device. The interface circuit provides source synchronous communication with the electronic device using a strobe signal. The interface circuit is configured to gate the strobe signal in order to successfully communicate with the electronic device.