Single-Wire Sensor Daisy Chain for High-Baud Asynchronous Data
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Solution Overview
Problem
Existing sensor systems face challenges in communicating multiple sensors via a single-wire line due to limitations in baud rate and the need for initialization, particularly in real-time systems, with push-pull configurations being preferred for better performance but not allowing interconnection in single-wire bus topologies.
Innovation Solution
A sensor system with asynchronous data transmission using a daisy chain configuration and a microcontroller, enabling bi-directional communication on a single-wire data line through a DART (Daisy Chain Asynchronous Receiver Transmitter) protocol, allowing sensors to be integrated in sequence and supporting higher baud rates up to 8,000 kBd.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If open drain circuits with integrated pull-up resistors are used for single-wire communication, then multiple sensors can be interconnected in a single-wire bus topology, but the baud rate is limited to approximately 115.4 kBd and signal quality at rising edges deteriorates
Solution Approach 1:
The patent inverts the traditional open-drain configuration by using push-pull output stages that can actively drive both high and low states. This inversion allows push-pull configured sensors to communicate in a daisy-chain topology despite push-pull outputs traditionally being unsuitable for multi-device single-wire buses. The microcontroller coordinates transmission timing to prevent conflicts, enabling high-speed communication (up to 8000 kBd) while maintaining daisy-chain connectivity.
2Speed
If push-pull configurations are used for data transmission, then better signal quality and faster transmission speeds are achieved, but multiple devices cannot be interconnected in a single-wire bus topology
Solution Approach 1:
The patent reverses the conventional wisdom that push-pull outputs cannot be used in multi-device single-wire buses. By implementing coordinated transmission control where the microcontroller manages timing and sensor nodes actively drive the line in push-pull mode, the system achieves both high-speed transmission and daisy-chain connectivity simultaneously.
Solution Approach 2:
Each sensor node in the daisy-chain configuration uses its own push-pull output stage to actively drive the data line, eliminating the need for external pull-up resistors or open-drain configurations. The sensors self-manage their output driving capability, enabling fast transmission while maintaining compatibility with the single-wire bus topology through coordinated control.
3Device complexity
If traditional single-wire communication systems are used, then device complexity is reduced, but initialization and addressing of sensors are required before communication
Solution Approach 1:
The patent implements preliminary action by pre-configuring each sensor node with a unique address and establishing transmission timing protocols during system setup. This preliminary configuration enables sensors to immediately engage in high-speed asynchronous communication without requiring runtime initialization sequences, reducing operational complexity while maintaining simple hardware architecture.
Data Source
AI summary
The present disclosure relates to a sensor system with asynchronous data transmission, wherein the sensor system includes at least two individual sensors, each sensor having a first I/O pin and a second I/O pin. The sensor system also includes a microcontroller with a transmit pin and a receive pin, and a single-wire data line by means of which the microcontroller is configured to communicate with the individual sensors via an asynchronous data protocol. The single-wire data line runs between the transmit pin and the receive pin of the microcontroller, and the individual sensors are arranged in a daisy chain and are integrated into the single-wire data line in sequence.