Gray-Coded DLL Strobe Lockout for Source Synchronous Receivers
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Solution Overview
Problem
Conventional receiver lockout techniques for source synchronous strobe signals in microprocessor systems are inadequate as they do not account for variations in bus clock frequency, voltage, temperature, and fabrication processes, leading to substandard error compensation and reduced effectiveness.
Innovation Solution
A dynamic source synchronous strobe receiving apparatus utilizing a delay-locked loop (DLL) that continuously updates the lockout interval based on bus clock frequency, voltage, and temperature variations, with a configurable mechanism to adapt to different transfer speeds and fabrication process variations, employing a 64-tap delay element and gray encoded select vectors to determine the lockout time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fixed logic mechanisms are employed to calculate lockout time, then device complexity is reduced, but reliability deteriorates due to inability to compensate for variations in bus clock frequency, voltage, temperature, and fabrication processes
Solution Approach 1:
The patent implements a dynamic lockout time adjustment mechanism that continuously adapts to variations in bus clock frequency, voltage, and temperature. The receiver mechanism dynamically selects from multiple lockout time values based on detected operating conditions, transforming the static fixed logic approach into a dynamic adaptive system that maintains reliability across varying environments.
Solution Approach 2:
The patent changes the parameter of lockout time from a fixed value to a variable that can be adjusted based on operating conditions. By implementing multiple lockout time values and selecting appropriate values based on detected frequency, voltage, and temperature variations, the system optimizes error compensation while maintaining reasonable device complexity through structured parameter management.
2Reliability
If worst-case scenarios are employed to ensure reliability, then reliability is improved, but productivity deteriorates due to overly conservative design constraints
Solution Approach 1:
The patent implements dynamic adaptation of lockout time based on actual operating conditions rather than relying on static worst-case assumptions. The receiver mechanism adjusts lockout duration in real-time according to detected frequency, voltage, and temperature variations, allowing the system to operate efficiently under normal conditions while maintaining reliability when variations occur.
Solution Approach 2:
The patent employs multiple lockout time parameters that can be selected based on operating conditions. Instead of using a single conservative worst-case value that degrades performance, the system maintains a set of lockout time values and selects the appropriate one based on actual environmental factors, optimizing both reliability and productivity.
3Reliability
If dynamic adjustment mechanisms are implemented to compensate for variations, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent implements a dynamic adjustment mechanism that monitors operating conditions and selects appropriate lockout time values. The mechanism uses a structured approach with predefined lockout time values and selection logic based on detected frequency, voltage, and temperature variations, achieving dynamic adaptation without excessive complexity through organized parameter management.
Solution Approach 2:
The patent manages complexity by implementing a structured parameter adjustment system with multiple lockout time values and clear selection criteria. The mechanism changes parameters based on detected operating conditions using organized logic that balances adaptability with implementation simplicity, avoiding the need for overly complex continuous adjustment circuits.
4Adaptability or versatility
If fixed lockout time is used, then ease of manufacture is improved, but adaptability deteriorates due to inability to account for process variations
Solution Approach 1:
The patent implements multiple lockout time parameters that can be selected based on operating conditions and fabrication process variations. The receiver mechanism includes structured logic to detect variations and select appropriate parameters, achieving adaptability through organized parameter management that maintains reasonable implementation simplicity through clear selection criteria and predefined values.
Solution Approach 2:
The patent creates a universal receiver mechanism that can adapt to different operating conditions and fabrication variations through a single integrated design. The mechanism uses a set of lockout time values and selection logic that handles multiple scenarios (frequency variations, voltage variations, temperature variations, and process variations) within a unified structure, achieving multi-functionality without requiring separate circuits for each condition.
Data Source
AI summary
An apparatus for locking out a source synchronous strobe receiver, including a delay-locked loop (DLL) and receivers. The DLL receives a reference clock, and generates a select vector and an encoded select vector. The select vector is employed to select a delayed version of the reference clock that lags the reference clock by a prescribed number of cycles. The select vector is reduced by an amount and is gray encoded to indicate a first time. The receivers are each coupled to the delay-locked loop. Each of the receivers receives the encoded select vector and a corresponding strobe, and locks out reception of die corresponding strobe for a configurable lockout lime following transition of the corresponding strobe. The encoded select vector is employed by a gray code mux therein to determine the configurable lockout time by selecting a delayed version of the corresponding strobe.