CAN Transceiver Line-Code Detection for Fast Mode Switching
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Solution Overview
Problem
Controller Area Network (CAN) transceivers face challenges in efficiently switching between transmission modes based on data encoding, leading to suboptimal communication performance due to reliance on encoded 'trigger messages' for mode changes.
Innovation Solution
The CAN transceiver is configured to operate in different transmission modes based on the presence or absence of a first line code, using pulse width measurements to determine the encoding, thereby enabling continuous mode signaling without explicit mode change messages, and includes a mode detector to switch between fast and slow transmission/receive modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the transceiver uses encoded trigger messages to switch between transmission modes, then mode changes can be signaled, but communication performance deteriorates due to suboptimal switching efficiency and mode-change-time delays
Solution Approach 1:
The patent applies continuity of useful action by using continuous line code encoding on the data stream to continuously signal the desired transmission mode. Instead of discrete trigger messages that cause interruptions, the line code encoding persists throughout the data transmission, allowing the transceiver to continuously adapt its mode without stopping or pausing communication. This eliminates mode-change-time delays and maintains uninterrupted data flow.
Solution Approach 2:
The patent applies preliminary action by encoding the transmission mode information in advance within the data stream itself using line code characteristics. The mode indication is prepared and embedded in the data before transmission begins, so the transceiver can detect and adapt to the appropriate mode proactively rather than waiting for explicit mode-switch commands during transmission. This preliminary encoding of mode information eliminates reactive switching delays.
2Reliability
If the transceiver detects line code encoding to determine transmission mode, then mode signaling becomes continuous and reliable, but device complexity increases due to the need for decoding functionality
Solution Approach 1:
The patent applies universality by designing the transceiver to handle multiple transmission modes through a single integrated line code decoding mechanism. Rather than requiring separate dedicated circuits for each mode or complex mode-switching logic, the universal line code decoder can interpret different line code encodings (such as Manchester, NRZ, or other differential codes) and automatically adapt the transmission parameters accordingly. This multi-functional approach achieves reliable mode signaling while minimizing additional hardware complexity.
Solution Approach 2:
The patent applies self-service by enabling the data stream itself to carry the mode signaling information through its line code encoding characteristics. The transmitted data performs dual functions: it conveys the actual information payload while simultaneously encoding the transmission mode indicators through its line code properties. This self-service mechanism eliminates the need for separate control channels or additional signaling overhead, achieving reliable mode detection without increasing device complexity.
Data Source
AI summary
A Controller Area Network, CAN, transceiver configured to be connected to a CAN bus comprising;a transmitter arrangement configured to transmit signalling on the CAN bus based on transmit data, configured to operate in a first or second transmission mode, the first transmission mode configured to transmit said signalling with a first property and the second transmission mode configured to transmit said signalling with a second, different, property;a receiver arrangement configured to receive signalling from the CAN bus;a receive output configured to provide received data to the CAN controller; andwherein the transmitter arrangement is configured to operate in one of the first or second transmission modes based on a determination that the transmit data is encoded with a first line code and otherwise operate in the other transmission modes, and wherein the transceiver includes a decoder configured to decode the first line code of the transmit data.