Daisy-Chained Serial Interfaces With Dynamic Addressing and PHY Switching
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Solution Overview
Problem
Conventional automotive and industrial communication protocols are limited in addressing multiple devices on a single bus, fix predefined physical layer interfaces, and lack the ability to monitor and recover from adverse impedance conditions, such as open/short circuits, which restricts flexibility and reliability in communication systems.
Innovation Solution
The implementation of dynamically addressable daisy-chained serial communication systems with configurable physical layer interfaces, allowing for ad-hoc connection of many devices in a serial manner, using interfaces like LVDS, CAN, and single-ended serial communication, and incorporating intelligent diagnostic features to detect and adapt to impedance states, enabling recovery from adverse conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional communication protocols (LIN, CAN) are used with predefined addressing, then device addresses are fixed and pre-assigned, but the number of uniquely addressable devices is limited (LIN < 16, CAN < 128)
Solution Approach 1:
The patent implements dynamic address assignment where device addresses are not fixed but assigned sequentially during system initialization. The host device assigns addresses to slave devices in daisy-chain configuration, allowing the system to adapt to any number of devices without pre-defined address limits, thus resolving the contradiction between quantity of devices and addressing flexibility
Solution Approach 2:
The communication protocol is designed to be universal and adaptable to different device quantities and configurations. The same protocol framework supports both small numbers of devices (fewer than 16) and large numbers of devices (up to 1000 or more) through dynamic address assignment and configurable daisy-chain topologies, eliminating the need for protocol-specific addressing schemes
2Adaptability or versatility
If a single type of physical layer interface is selected for the transmission line, then the interface is simple to implement, but it cannot adapt to different communication environments (e.g., TTL interfaces have poor EMI characteristics, LVDS interfaces have compatibility issues with single-ended MCUs)
Solution Approach 1:
The patent applies local quality by allowing different physical layer interface types (TTL, LVDS, differential, single-ended) to be selected at each slave device location based on local communication environment requirements. Each slave device can be configured with the appropriate interface type for its specific application, enabling optimal EMI performance and MCU compatibility without requiring all devices to use the same interface
Solution Approach 2:
The system enables parameter changes in the physical layer interface configuration, allowing the interface type (differential vs. single-ended, LVDS vs. TTL) to be changed based on communication distance, EMI requirements, and MCU compatibility needs. This configurability resolves the contradiction between adaptability and complexity by providing interface diversity only where needed
3Reliability
If conventional communication protocols are used without impedance monitoring, then the system is simpler to implement, but it cannot detect or recover from adverse impedance conditions (open/short circuits, mechanical degradation, PCB defects)
Solution Approach 1:
The patent implements feedback mechanisms where slave devices continuously monitor impedance conditions on the transmission line and report status to the host device. When adverse conditions (open/short circuits, degradation) are detected, the system provides feedback signals that enable the host to identify the problematic device and initiate recovery procedures, thus improving reliability through active monitoring without requiring overly complex diagnostic hardware
4Quantity of substance
If devices are connected in a daisy-chain configuration with dynamic addressing, then up to 1000 devices can be connected, but the addressing and initialization protocol becomes more complex
Solution Approach 1:
The patent applies preliminary action by performing address assignment and device initialization in a systematic sequence during system startup. The host device assigns addresses to slave devices in daisy-chain order before normal communication begins, and implements impedance monitoring and device registration in advance. This preliminary organization simplifies the overall protocol complexity by establishing device identities and communication parameters before operational complexity arises
Data Source
AI summary
Facilitating ad hoc daisy-chaining of dynamically addressable devices having configurable physical layer interfaces together in a serial manner is presented herein. A system can include a group of devices communicatively coupled with respective devices of the group of devices in a daisy-chained manner via physical layer (PHY) interfaces of the respective devices including a group of available communication protocol configurations including a low voltage differential signaling (LVDS) based PHY configuration, a controller area network (CAN) based PHY configuration, and/or a single-ended serial communication PHY configuration including a complementary metal-oxide-semiconductor (CMOS) based interface or a transistor-transistor logic (TTL) based interface. Further, a host device of the system is directly connected, using a single-ended Manchester encoded serial communication interface, to a foremost device of the group of devices and to successive devices of the respective devices, via the foremost device, using the single-ended Manchester encoded serial communication interface.