Serial Bus Subscriber Station for CAN XL Resynchronization
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Solution Overview
Problem
In serial bus systems like CAN XL, synchronization issues arise during error handling, particularly due to irradiation, leading to incorrect reintegration of receiving nodes and loss of synchronization edges, which compromises communication robustness and efficiency.
Innovation Solution
A subscriber station with a communication control device that modifies the DAS field by inserting a field with a predetermined length before the synchronization edge, ensuring all nodes synchronize correctly, even after errors, by adjusting bit times between communication phases and using pulse width modulation to switch operating modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If error signaling is used in CAN XL, then communication robustness is improved, but device complexity increases due to additional error handling mechanisms
Solution Approach 1:
The system uses self-service by having the transmitting node independently detect communication failures through timeout mechanisms without requiring external error signals from receiving nodes. The transmitter monitors for acknowledgments and automatically retransmits data when failures are detected, eliminating the need for complex error signaling infrastructure.
Solution Approach 2:
The invention extracts and removes the error signaling function from the receiving nodes, concentrating error detection and handling responsibilities solely at the transmitting node. This simplifies the overall system by eliminating error signaling mechanisms at receiver ends while maintaining robust error handling through transmitter-side monitoring and retransmission.
2Productivity
If transceiver switches between fast and slow operating modes, then data transmission rate is improved, but synchronization stability deteriorates during mode transitions
Solution Approach 1:
The system applies preliminary action by pre-synchronizing all receiving nodes to the transmitting node's clock before fast-mode data transmission begins. The transmitter sends synchronization information in advance during slow-mode arbitration phase, ensuring all nodes are properly synchronized before the high-speed phase starts, thus preventing synchronization issues during mode transitions.
Solution Approach 2:
The invention implements dynamics by allowing the transceiver to dynamically switch between slow and fast operating modes based on communication phase requirements. The system adapts its transmission speed dynamically - using slow mode for arbitration and synchronization, then switching to fast mode for data transmission, with automatic mode changes controlled by the transmitting node.
3Device complexity
If fire and forget communication is used, then device complexity is reduced, but loss of information increases when errors occur
Solution Approach 1:
The system implements feedback through timeout mechanisms where the transmitting node monitors for acknowledgments from receiving nodes. When no acknowledgment is received within a predetermined time period, the transmitter infers communication failure and automatically retransmits the data, ensuring information integrity without requiring complex explicit acknowledgment protocols.
Solution Approach 2:
The transmitting node performs self-service error detection and correction by monitoring communication status and autonomously initiating retransmissions when failures are detected. This approach maintains simple fire-and-forget communication from the receiver side while ensuring data accuracy through transmitter-side error handling and automatic retransmission.
Data Source
AI summary
A subscriber station for a serial bus system. The subscriber station has a communication control device for controlling a communication of the subscriber station with at least one other subscriber station of the bus system. The communication control device generates a transmit signal according to a frame and inserts a field having an edge into the frame after a second communication phase. The field has, before the edge, a predetermined length corresponding to a time period that is longer than the time period of a bit time of a first communication phase. The edge is provided for synchronization to the communication on the bus for a communication control device of the at least one other subscriber station of the bus system whose transceiver device is switched, before the predetermined time period, into an operating mode for transmitting and receiving the frame in the first communication phase.