CAN-FD Bus Transceiver Compatibility via Data Substitution
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Solution Overview
Problem
The transition from CAN to CAN FD communication networks is challenging due to incompatibility issues, where previous CAN bus participants cannot process CAN FD messages without hardware and software changes, leading to errors and incompatibility in mixed communication networks.
Innovation Solution
Adapting CAN FD messages into CAN messages by replacing user data with substitute data at a lower transmission rate, allowing CAN bus participants to receive and process CAN FD messages without errors, using bus transceivers that convert CAN FD messages to CAN messages during reception, ensuring compatibility without altering existing hardware or software.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If CAN FD messages are transmitted at higher speed with extended user data fields, then transmission rate and data capacity are improved, but compatibility with existing CAN bus participants is lost
Solution Approach 1:
A transceiver-level conversion mechanism is introduced as an intermediary between CAN FD messages and legacy CAN bus participants. The transceiver detects CAN FD messages on the bus and automatically converts them into CAN-compatible format with appropriate substitution of user data, allowing legacy participants to receive and process the messages without hardware or software changes while maintaining backward compatibility
2Adaptability or versatility
If hardware changes are made to enable CAN FD compatibility, then ability to process CAN FD messages is improved, but device complexity and cost increase
Solution Approach 1:
The transceiver is designed with multi-functionality to handle both traditional CAN messages and CAN FD messages. By integrating automatic detection and conversion capabilities into the existing transceiver hardware, the system can process multiple message types without requiring separate hardware components, thereby reducing overall system complexity and cost
3Adaptability or versatility
If software updates are implemented for CAN FD support, then message processing capability is improved, but system complexity and update requirements increase
Solution Approach 1:
The transceiver automatically performs detection and conversion of CAN FD messages without requiring software updates or intervention from the control unit. The conversion process is handled autonomously at the transceiver level, maintaining the existing software architecture while enabling CAN FD compatibility
Data Source
AI summary
The CAN-FD communication network for transmitting messages at different transmission speeds is provided with a bus line (10) and several bus participants (14, 16), each of which has a bus transceiver (22) connected to the bus line (10) and a control unit (18) coupled to it, among other things for converting messages received via the bus line (10) and for generating messages to be sent via the bus line (10), wherein each message contains control data and user data.The messages comprise first messages, whose payload data is transmitted over the bus line (10) at a first speed, and second messages, whose payload data is transmitted over the bus line (10) at a second speed greater than the first speed, wherein the control data of each message contains an encoding representing the transmission speed of the payload data of the message in question.The bus participants (14, 16) comprise first bus participants (14), which can only process first payload data, and second bus participants (16), which can process both first and second messages, wherein the bus transceiver (22) of each first bus participant, upon detection of the encoding indicating the second payload data transmission rate during the reception of a second message, replaces the payload data of this second message with substitute payload data and transmits this substitute payload data to the control unit (18) at the first rate.