Master-Slave Time Synchronization Validation on Private Buses
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current time synchronization methods for controllers connected via private buses, such as PCI Express, CAN-FD, or MIPI, lack the implementation of Precision Time Protocol (PTP), which is essential for ensuring the integrity of time synchronization and fulfilling Automotive Safety Integrity Levels (ASIL) required for autonomous or automated vehicles.
Innovation Solution
A method for validating time synchronization between a master and slave controller via a private bus, where the master controller sends a follow-up message with its global time, and the slave controller responds with its global time, using local hardware counters to check synchronization differences within predefined thresholds, effectively emulating PTP to ensure ASIL B or higher safety integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PTP implementation is used for time synchronization via Ethernet bus, then time synchronization integrity is improved, but this approach is not available for private bus systems
Solution Approach 1:
The patent copies the essential functionality of PTP time synchronization protocol and implements it through a simplified master-slave communication mechanism on private bus systems. The master controller sends time synchronization messages containing global time information, and slave controllers respond with their local time, enabling PTP-like time synchronization without requiring full PTP protocol implementation on unsupported bus systems.
2Reliability
If multiple communication busses are used for autonomous driving functions, then safety requirements are improved, but system complexity increases
Solution Approach 1:
The patent creates a universal time synchronization mechanism that can operate across multiple different bus types (CAN-FD, LIN, Ethernet, FlexRay) through a common master-slave protocol. This multi-functional approach allows the same time synchronization architecture to serve various communication infrastructure requirements in autonomous driving systems, reducing overall system complexity while maintaining safety standards.
3Measurement precision
If time synchronization validation is performed continuously, then synchronization accuracy is improved, but communication overhead increases
Solution Approach 1:
The patent implements periodic time synchronization validation where the master controller sends time synchronization messages at regular intervals, and slave controllers periodically respond with their time information. This periodic approach maintains synchronization accuracy by continuously monitoring time differences while managing communication overhead through structured, interval-based exchanges rather than continuous validation.
Data Source
AI summary
A method includes sending, from the master controller to the slave controller, a follow up message in response to a pull of a predefined pin, wherein the follow up message includes a global time of the master controller when the predefined pin was pulled; sending, from the slave controller to the master controller, a validation message in response to the received follow up message, wherein the validation message includes a global time of the slave controller when the pull of the predefined pin is detected by the slave controller; and validating the time synchronization by checking, at the master controller and/or the slave controller, if a difference between the global time of the master controller when the predefined pin was pulled and the global time of the slave controller when the pull of the predefined pin is detected by the slave controller is smaller than a predefined first threshold.