In-System CAN Node Configuration for ID Assignment and Location Mapping
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Solution Overview
Problem
Conventional CAN devices require complex and costly logistics for programming unique identifiers and identifier masks, and lack accurate location information for network nodes, especially when configurations are revised or updated.
Innovation Solution
A controller area network system with in-system configuration, utilizing a serial conductor bus and a leader device to program configurable CAN devices by switching between common and differential modes, generating test clocks, and interfacing media access control circuitry to assign unique identifiers and masks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CAN devices are programmed with unique identifiers during the assembly process, then bus access conflicts are resolved, but complex and costly logistics are required for configuration revisions
Solution Approach 1:
The patent implements dynamic reconfigurability by allowing CAN devices to change their identifiers and configuration parameters after initial assembly. The system transitions from static pre-programmed IDs to dynamic in-system configuration, enabling logistics simplification through post-assembly programming capabilities.
Solution Approach 2:
The patent prepares devices with placeholder or default identifiers during assembly, which are then replaced with final unique identifiers through in-system configuration. This preliminary action allows devices to function temporarily with generic IDs while maintaining the ability to resolve conflicts later without complex logistics.
2Reliability
If CAN devices are assigned fixed identifiers, then content-based arbitration works, but configuration updates become costly and complex
Solution Approach 1:
The system enables dynamic reassignment of CAN device identifiers and configuration parameters through in-system programming. This allows manufacturers to update device IDs, masks, and other parameters without physical rework or complex logistics, significantly reducing configuration update costs while maintaining arbitration functionality.
Solution Approach 2:
The patent changes the state of configuration parameters from fixed to programmable. By implementing in-system configuration capabilities, the system allows modification of identifier parameters, masks, and device settings after assembly, eliminating the need for costly rework during configuration updates.
3Stability of the object's composition
If device identifiers are permanently assigned, then arbitration is stable, but location information accuracy decreases when nodes move
Solution Approach 1:
The patent implements dynamic identifier assignment that can track and reflect physical node locations. When CAN devices move to different positions in the network, their identifiers can be updated through in-system configuration to maintain accurate location information, thereby improving measurement precision without compromising arbitration stability.
Data Source
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AI summary
A controller area network (CAN) system including a serial conductor (S) bus, a CAN bus, at least one configurable CAN device, and a leader device. Each configurable CAN device is inserted on the S bus and includes media access control (MAC) circuitry and physical medium circuitry. The physical medium circuitry forwards test clocks from the CAN bus to clock internal latches when the CAN bus is in a common mode and interfaces the MAC circuitry for programming via the CAN bus when the CAN bus is in a differential mode. The leader device drives the S bus between first and second logic states, switches the CAN bus between the common and differential modes, generates test clocks on the CAN bus to place a selected configurable CAN device in programming mode, and programs the selected configurable CAN device via the CAN bus.