CAN XL Subscriber Station Threshold Switching for Phase Detection
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Solution Overview
Problem
Existing subscriber stations in CAN XL bus systems struggle to reliably integrate into ongoing communication due to the inability to distinguish between arbitration and data phases, leading to errors and reduced data transmission rates.
Innovation Solution
A device for a subscriber station with a receiving block that switches reception thresholds based on detected bus levels, allowing it to automatically adapt to different communication phases and correctly identify idle states, ensuring seamless integration and high error robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single reception threshold is used in CAN XL bus systems, then the device complexity is reduced, but the reliability of detecting bus levels in different communication phases deteriorates
Solution Approach 1:
The patent implements dynamic switching between different reception thresholds based on the detected communication phase. The receiving block automatically selects the first reception threshold during arbitration phase and the second reception threshold during data phase, allowing the system to adapt its detection characteristics to the current operating conditions rather than using a static threshold configuration
Solution Approach 2:
The patent changes the reception threshold parameter according to the communication phase. By switching between at least two different reception thresholds (first threshold for arbitration phase, second threshold for data phase), the system optimizes its detection capability for each specific phase while maintaining manageable device complexity through automated phase-based selection
2Adaptability or versatility
If subscriber stations switch on during ongoing CAN XL communication, then the system adaptability is improved, but the reliability of integration into ongoing communication deteriorates due to inability to detect idle states
Solution Approach 1:
The patent enables newly switched-on subscriber stations to first detect the current communication phase by monitoring bus levels with appropriate thresholds before attempting to integrate into communication. This preliminary detection allows the station to understand whether it is in arbitration or data phase, enabling reliable synchronization with ongoing communication
Solution Approach 2:
The patent implements a feedback mechanism where the receiving block continuously monitors bus levels and uses this information to determine the communication phase and idle states. This feedback loop allows subscriber stations to dynamically adjust their reception parameters and correctly identify when the bus is idle, enabling reliable integration even when switching on during ongoing communication
3Productivity
If higher data rates are implemented in CAN XL, then the productivity is improved, but the error robustness deteriorates due to asymmetric bus level deformation
Solution Approach 1:
The patent dynamically adjusts the reception threshold based on the communication phase to compensate for asymmetric bus level deformation. During data phase at higher data rates, the system uses a specifically optimized second reception threshold that accounts for the deformation characteristics, thereby maintaining error robustness despite the increased transmission rate
Solution Approach 2:
The patent changes the reception threshold parameter to match the specific characteristics of each communication phase. By using different thresholds optimized for arbitration phase and data phase respectively, the system maintains reliable detection accuracy even at higher data rates where asymmetric deformation becomes more significant
Data Source
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AI summary
The invention relates to a device (12; 16; 32) for a serial bus system (1) and to a method for communicating in a serial bus system (1). The device (12; 16; 32) has a receiving block (122) for receiving a signal (VDIFF) from a bus (40) of the bus system (1), said signal (VDIFF) being based on a transmission signal (TxD) with which a message (45) is exchanged between subscriber stations (10, 20, 30) of the bus system (1), wherein the receiving block (122) is designed to receive the signal (VDIFF) in a first communication phase (451; 453, 451), in which a recessive bus state (401) can be overridden by a dominant bus state (402) in the signal (VDIFF), with a first reception threshold (T_a) and to receive the signal (VDIFF) in a second communication phase (452), in which states other than the recessive and dominant states (401, 402) are present in the signal (VDIFF), with a second reception threshold (T_d); an analysis block (151) for analyzing a signal (VDIFF) from the bus (40) of the bus system (1) with a switchover reception threshold (T_c), which differs from the first reception threshold (T_a) and the second reception threshold (T_d); and a reception threshold switching block (152) for temporarily switching the reception threshold of the receiving block (122) from the first reception threshold (T_a) to the second reception threshold (T_d) if the analysis block (151) detects the bus level (VDIFF_1) for Data_1 of the transmission signal (TxD) with the switchover reception threshold (T_c) in the signal (VDIFF).