Dynamic Time-Out for Data Link Mode Switching
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Solution Overview
Problem
Existing methods for switching between operation modes in data communication links, such as MIPI D-PHY, face challenges in determining an appropriate time-out period, especially when transitioning from low-speed (LP) to high-speed (HS) mode, due to varying clock speeds, leading to unnecessary delays and inefficiencies.
Innovation Solution
A receiver that detects a request signal to switch modes, measures its duration, and uses this measurement to determine a time-out period, allowing the system to autonomously adjust and avoid involving higher protocol layers, with options for digital or analogue implementations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed number of HS clock cycles is used to determine the time-out period, then the time-out period is sufficient for high clock speeds, but it becomes excessively long for low clock speeds
Solution Approach 1:
The patent implements a dynamic time-out determination mechanism that adapts to varying clock speeds. Instead of using a fixed number of clock cycles, the system measures the actual duration of the LP mode request signal and scales the time-out period proportionally. This allows the time-out to be appropriately short for high clock speeds and sufficiently long for low clock speeds, resolving the contradiction between reliability and time loss.
Solution Approach 2:
The patent changes the parameter used for time-out determination from a fixed clock cycle count to a measured signal duration. By measuring the actual time length of the LP mode request signal and using this as the basis for the HS mode time-out period, the system automatically adjusts the time-out parameter according to the actual operating conditions, eliminating the need for conservative over-estimation.
2Loss of time
If a programmable number of clock cycles is used to determine the time-out period, then the time-out can be optimized for current clock speed, but it requires re-programming when speed changes occur
Solution Approach 1:
The patent implements a self-adjusting time-out mechanism that automatically adapts to clock speed changes without requiring external re-programming. The system continuously measures the duration of incoming LP mode request signals and automatically scales the subsequent HS mode time-out period based on these measurements. This self-service approach eliminates the need for higher protocol layers to re-program timers when speeds change, reducing device complexity while maintaining optimization.
Solution Approach 2:
The patent employs a feedback mechanism where the measured duration of LP mode request signals is used to dynamically adjust the HS mode time-out period. This closed-loop approach ensures that the time-out is always optimized for the current operating conditions without requiring manual intervention or re-programming, as the system automatically responds to changes in clock speed through continuous measurement and adjustment.
3Reliability
If the receiver waits for a long time-out period to ensure reliable mode switching, then mode switching reliability is improved, but communication efficiency decreases
Solution Approach 1:
The patent changes the time-out parameter from a fixed conservative value to a dynamically scaled value based on actual signal measurements. By measuring the duration of LP mode request signals and proportionally setting the HS mode time-out period, the system achieves the minimum necessary waiting time for reliable mode switching without adding unnecessary delays, thereby maintaining communication efficiency while ensuring reliability.
Solution Approach 2:
The patent avoids excessive waiting by implementing a time-out period that is precisely tailored to the actual operating conditions rather than using a uniformly long timeout. The measured duration of the request signal provides the exact amount of time needed for mode transition, eliminating the excessive action of waiting longer than necessary and thus preserving communication efficiency while maintaining adequate reliability.
Data Source
AI summary
A method and apparatus for determining a time-out period used for switching between a first operational mode and a second operational mode of a data communications link, comprising detecting a signal used to request switching from the first operational mode to the second operational mode; measuring the duration of the signal; and determining the time-out period in dependence on the measured duration of the signal.