Master-Slave CAN FD Bus for Low-Cost Vehicle Lighting Links
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Solution Overview
Problem
Existing high data rate vehicle communication systems, such as those for automotive LED lighting, are costly due to the need for complex protocol controllers and accurate clock sources, which increases production costs and complexity, especially in distributed lighting systems.
Innovation Solution
A master-slave communication bus interface using the CAN FD protocol with differential bus wiring and cyclic redundancy check for error detection, allowing for cost-effective high data rate networks that comply with automotive safety and robustness requirements, while avoiding the need for accurate clock sources and reducing production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If complex protocol controllers and accurate clock sources are used to achieve high data rate communication, then communication speed and reliability are improved, but production cost and device complexity increase
Solution Approach 1:
The patent extracts the clock source function from the protocol controller, using an external crystal oscillator instead of an integrated clock generator. This separation allows the protocol controller to be simpler and less expensive while maintaining high data rate communication capability through the external accurate clock source.
Solution Approach 2:
The patent introduces an external crystal oscillator as an intermediary component that provides accurate timing signals to the protocol controller. This mediator enables the controller to achieve high precision timing without having complex internal clock generation circuits, thus reducing device complexity while maintaining high data rate performance.
2Reliability
If complex protocol controllers and accurate clock sources are used to ensure automotive safety and robustness, then reliability is improved, but production cost increases
Solution Approach 1:
The patent combines the protocol controller with external standard components (crystal oscillator and differential transceiver) to achieve automotive-grade reliability. This combination approach allows each component to be optimized independently and manufactured using standard processes, reducing overall production cost while maintaining high reliability through proven external components rather than complex integrated solutions.
Solution Approach 2:
The patent uses standard, readily available external components (crystal oscillators and differential transceivers) that can be manufactured cheaply using established processes. These components are designed for high reliability and are widely produced, making them cost-effective for automotive applications compared to custom-integrated complex protocol controllers.
3Reliability
If differential wiring is adopted for clock and data signals to facilitate robustness, then communication reliability is improved, but wire harness cost increases
Solution Approach 1:
The patent uses the same differential bus wiring for both clock and data signals, making the wiring structure multi-functional. Instead of separate differential pairs for clock and data, the system uses a single differential bus that carries both types of signals, reducing the quantity of wiring material while maintaining robustness through differential signaling for all communications.
Data Source
AI summary
A device includes a master device, a set of slave devices and a bus. The master device is configured to transmit first messages carrying a set of operation data message portions indicative of operations for implementation by slave devices of the set of slave devices, and second messages addressed to slave devices in the set of slave devices. The second messages convey identifiers identifying respective ones of the slave devices to which the second messages are addressed requesting respective reactions towards the master device within respective expected reaction intervals. The slave devices are configured to receive the first messages transmitted from the master device, read respective operation data message portions in the set of operation data message portions, implement respective operations as a function of the respective operation data message portions read, and receive the second messages transmitted from the master device.