CAN Bus In-System Configuration for Dynamic Node ID Assignment
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Solution Overview
Problem
Conventional CAN devices require complex and costly logistics for programming unique identifiers and identifier masks during assembly, and lack accurate location information for network nodes when their position changes.
Innovation Solution
A controller area network system with in-system configuration, utilizing a leader device to program configurable CAN devices via a serial conductor (S) bus, which includes media access control (MAC) and physical medium circuitry, allowing for dynamic assignment of identifiers and location tracking through a serial bus interface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CAN devices are programmed with unique identifiers during assembly, then bus access conflicts are resolved, but logistics complexity and costs increase
Solution Approach 1:
The patent implements dynamic identifier assignment where CAN device identifiers are not fixed during assembly but are dynamically configured in-system based on the device's physical location in the network. The leader device assigns identifiers to follower devices based on their position, allowing the system to adapt to changes in network topology without complex reprogramming logistics.
Solution Approach 2:
The system enables self-configuration where follower devices automatically receive their identifiers from the leader device through the S bus. This eliminates the need for manual programming during assembly, as devices configure themselves when inserted into the network, significantly reducing logistical complexity.
2Stability of the object's composition
If CAN device identifiers are irrevocably assigned, then device identity is stable, but configuration updates become costly and complex
Solution Approach 1:
The patent creates a dynamic configuration system where device identifiers can be updated by the leader device at any time. When network topology changes or devices are repositioned, the leader device automatically reassigns identifiers through the S bus without requiring physical access to each device, enabling easy configuration updates while maintaining stable device identities during normal operation.
3Ease of operation
If fixed identifiers are assigned to CAN devices, then arbitration is straightforward, but location information accuracy is lost when nodes move
Solution Approach 1:
The system implements feedback through the S bus where the leader device continuously monitors the physical positions of follower devices and dynamically adjusts identifier assignments accordingly. This feedback mechanism ensures that device identifiers always reflect their current location in the network, maintaining both accurate location information and functional arbitration.
Data Source
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.