Wired Bus Address Assignment via Bitwise ID Arbitration
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Solution Overview
Problem
Existing arbitration methods in wired bus systems face challenges with timing errors due to oscillator tolerances, leading to unreliable arbitration, especially during network initialization, and require complex protocols or expensive hardware for precise synchronization.
Innovation Solution
A method for assigning unique network addresses using low-cost oscillators, allowing flexible and efficient arbitration by transmitting a subset of identification number bits, dynamically adjusting granularity based on collision thresholds, and utilizing CRC for error detection, enabling rapid address assignment without additional hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional arbitration methods using precise crystal oscillators are used, then timing accuracy is improved, but device cost and complexity increase
Solution Approach 1:
The patent replaces expensive crystal oscillators with inexpensive RC oscillators in responder devices. The system accepts that RC oscillators are less precise but compensates through protocol design - the commander uses a precise oscillator while responders use cheap oscillators, and the arbitration protocol is designed to handle the timing variations without requiring all devices to have expensive oscillators.
Solution Approach 2:
The patent changes the arbitration approach from time-based comparison (which requires precise oscillators) to bit-by-bit ID comparison. The commander sends arbitration frames with candidate ID bits, and responders compare these bits with their own ID bits. This parameter change from temporal to combinatorial arbitration eliminates the need for precise timing synchronization across all devices.
2Measurement precision
If the number of transmitted arbitration bits is increased, then identification accuracy is improved, but the common decision window narrows and timing errors overlap
Solution Approach 1:
The patent segments the arbitration process into multiple independent bit comparison stages. Instead of transmitting all ID bits simultaneously and requiring a common decision window, the system segments the ID into individual bits and processes them sequentially. The commander sends arbitration frames containing candidate bit values, and each bit is resolved in a separate time slot, eliminating the need for a narrow common decision window.
Solution Approach 2:
The patent introduces dynamic adaptation in the arbitration process. The commander monitors whether arbitration bits are resolved quickly or slowly and adjusts the arbitration strategy accordingly. If bits are resolved quickly, the system can proceed to more bits; if timing errors cause conflicts, the system can retry or adjust the approach. This dynamic behavior optimizes the balance between identification accuracy and arbitration time.
3Adaptability or versatility
If a unique ID system is implemented across nodes from different manufacturers, then interoperability is improved, but the arbitration process becomes more complex
Solution Approach 1:
The patent implements a universal arbitration protocol that works with devices from different manufacturers. Each device contains a unique ID (such as a serial number), and the arbitration system universally handles these IDs through standardized bit-by-bit comparison. The commander can arbitrate between any number of devices with any ID format, making the system universally applicable across different manufacturers and device types.
Solution Approach 2:
The commander acts as an intermediary that mediates the arbitration process between multiple responders. Instead of requiring direct comparison between all device pairs (which would be complex), the commander receives arbitration frames from all responders, compares their ID bits centrally, and determines the winning device. This intermediary approach simplifies the protocol by centralizing the complex comparison logic in one device.
4Productivity
If arbitration is performed during network initialization, then address assignment is achieved, but timing errors accumulate and overlap leading to loss of common decision window
Solution Approach 1:
The patent enables responders to self-identify and self-register their unique IDs with the commander during initialization. Each responder transmits its ID bits in response to commander queries, and the commander automatically processes these transmissions to assign addresses. This self-service approach eliminates the need for complex centralized timing control, as each device independently transmits its ID when prompted, accommodating RC oscillator variations without requiring tight synchronization.
Data Source
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AI summary
A method of assigning an address on a wired network comprising at least one commander and a plurality of responders is provided. A value of a subset of bits sent by the commander is compared with the ID of each responder. The responders that find a match send their IDs or a part of their ID. If there is a collision, a new value is sent. If only one responder has a match, the commander assigns that responder a node address which is shorter than the ID.