CAN Transceiver Mode Switching Without Extra Pins
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Solution Overview
Problem
Current CAN transceiver technologies lack efficient mechanisms to dynamically switch between different operational modes, such as FAST-RX and SLOW modes, without additional signaling pins, which complicates mode transitions and can lead to improper network synchronization and communication errors.
Innovation Solution
A controller and transceiver system that uses existing data terminals to provide a controller-mode-signal by driving currents on the first and second data terminals, allowing the transceiver to switch modes based on differential signal encoding and logic level changes, enabling unconditional mode changes and robust communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additional signaling pins are added to enable mode switching, then mode transition capability is improved, but device complexity and pin count increase
Solution Approach 1:
The existing data terminals are made multi-functional by enabling them to carry both data signals and mode signaling functions. The controller drives both data terminals with identical signals during mode transition periods, allowing the transceiver to detect the mode change request through its differential signaling infrastructure without requiring dedicated mode control pins.
Solution Approach 2:
The mode signaling function is merged with the existing data signaling infrastructure. Instead of separating mode control into dedicated pins, the patent combines mode transition requests with the differential data signal paths, using the same physical medium for both data transmission and mode control.
2Adaptability or versatility
If mode switching is enabled without proper signaling mechanisms, then adaptability is improved, but communication reliability deteriorates due to synchronization errors
Solution Approach 1:
The transceiver monitors the differential signal at its input terminals to detect mode transition requests. When it detects that both terminals are driven identically (indicating a mode request rather than data), it transitions its internal mode and adjusts its operation accordingly, ensuring synchronized mode changes across the communication interface.
Solution Approach 2:
The controller prepares for mode transition by driving both data terminals with identical signals before the actual mode change occurs. This preliminary signaling allows the transceiver to detect and prepare for the mode transition in advance, ensuring smooth and synchronized switching without communication errors.
3Ease of operation
If dedicated mode control pins are used, then mode transition control is simplified, but device complexity and power consumption increase
Solution Approach 1:
The data terminals serve dual purposes: transmitting data during normal operation and conveying mode transition requests when driven identically. This eliminates the need for separate mode control pins while maintaining full mode switching capability through the existing terminal infrastructure.
4Reliability
If additional control circuitry is added for mode switching, then mode transition reliability is improved, but power consumption increases
Solution Approach 1:
The transceiver uses its existing differential signaling infrastructure and input monitoring capabilities to detect mode transitions. No additional dedicated control circuitry is required - the same circuits used for data reception are repurposed to detect and respond to mode transition requests, minimizing additional power consumption.
Data Source
Figure 1a~1b
Figure 2~3
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AI summary
The disclosure relates to a controller and a transceiver and associated software and methods. A controller for communicating with a transceiver in a network node having a first mode of operation and a second mode of operation, the controller comprising: a first-data-terminal for communicating with the transceiver; and a second-data-terminal for communicating with the transceiver, in which the controller is configured to: in the second mode, determine receive-data based on a first-data-signal at the first-data-terminal and a second-data-signal at the second-data-terminal; determine that a change of mode from the second mode to the first mode is required; and in response to determining that a change of mode from the second mode to the first mode is required, provide a controller-mode-signal that instructs the transceiver to operate in the first mode rather than the second mode, wherein the controller-mode-signal is provided by simultaneously driving a first current on the first-data-terminal and a second current on the second-data-terminal.