Bus Transceiver Substituting CAN-FD Payloads for Legacy Compatibility
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Solution Overview
Problem
The transition from CAN to CAN-FD standards requires significant changes in hardware and software for bus participants, making it difficult to maintain compatibility and preventing older CAN bus participants from processing CAN-FD messages without generating error indications.
Innovation Solution
A communication network architecture that includes bus transceivers capable of detecting CAN-FD messages and substituting their payloads with a substitute payload at a lower rate, allowing CAN bus participants to process these messages without errors, and optionally using converters to achieve this compatibility without altering existing hardware and software.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the transmission rate is increased to CAN-FD standards, then data transmission efficiency is improved, but compatibility with older CAN bus participants deteriorates
Solution Approach 1:
A transceiver is introduced as an intermediary device between the CAN-FD bus and older CAN bus participants. The transceiver detects CAN-FD messages on the bus, substitutes their payloads with substitute payloads formatted for CAN compatibility, and transmits these converted messages to older CAN bus participants at CAN transmission rates, thereby enabling communication between incompatible systems
Solution Approach 2:
The system dynamically changes transmission parameters based on message type. CAN-FD messages are transmitted at higher data rates between compatible participants, while messages destined for older participants are converted and transmitted at lower CAN rates. The transceiver detects the original message rate via coding in control data and adjusts the output rate accordingly
2Speed
If hardware and software are updated to support CAN-FD, then transmission rate capability is improved, but system complexity and adaptation cost increase
Solution Approach 1:
The transceiver serves as a mediator that handles all the complexity of CAN-FD protocol interpretation and message conversion. Older CAN bus participants with simpler hardware and software remain unchanged, while the transceiver absorbs the complexity of detecting CAN-FD messages, substituting payloads, and managing dual-rate transmission protocols
Solution Approach 2:
The transceiver creates substitute payloads that are copies or representations of the original CAN-FD message payloads, formatted in a manner compatible with older CAN participants. This allows older participants to process messages without needing to understand or support the CAN-FD protocol
3Adaptability or versatility
If CAN bus participants process CAN-FD messages directly, then future-proofing is improved, but error indications are generated due to incompatible payload formats
Solution Approach 1:
The transceiver performs preliminary actions by detecting CAN-FD messages before they reach older CAN bus participants and substituting their payloads in advance. This prevents the incompatible payload formats from causing error indications in older participants, while still allowing the system to support future CAN-FD functionality
Data Source
AI summary
The communication network for transmission of messages at different transmission rates comprises a bus line and a plurality of bus participants each of which includes a bus transceiver connected to the bus line and a control unit coupled with said bus transceiver, inter alia, for converting messages received via the bus line and for generating messages to be sent via the bus line, wherein each message includes control data and payload. The messages include first messages whose payload is transmitted via the bus line at a first rate and second messages whose payload is transmitted via the bus line at a second rate which is higher than the first rate, wherein the control data of each message contain a coding representing the transmission rate of the payload of the respective message. The bus participants include first bus participants which can exclusively process a first payload and second bus participants which can process both first and second messages, wherein the bus transceiver of each first bus participant, upon detection of the coding indicating the second payload transmission rate when receiving a second message, substitutes the payload of this second message by a substitute payload and transmits this substitute payload at the first rate to the control unit.