Mixed-Mode Serial Bus Interface for One-Wire and Two-Wire Communication

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Solution Overview

Problem

Current serial communication technologies face challenges in efficiently managing communication between devices configured for one-wire and two-wire communication, particularly in mobile communication devices with complex bus architectures, where increased functionality and stringent timing constraints demand improved GPIO and communication link throughput.

Innovation Solution

The method involves transmitting a sequence start condition over a serial bus to indicate whether clock pulses are provided concurrently with data, using pulse-width modulation and phase modulation to encode data, and embedding timing information in the data signal, allowing for efficient communication with both one-wire and two-wire slave devices on a shared bus.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple separate communication interfaces are used to support both one-wire and two-wire devices, then device functionality and communication versatility are improved, but the number of I/O pins and bus architecture complexity increase

Engineering Contradiction:
Improvecommunication interface versatilityVSAvoidbus architecture complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The serial bus is designed to operate in multiple modes (first mode with separate clock and data lines, second mode with clock embedded in data line) allowing a single bus architecture to support both one-wire and two-wire communication protocols, eliminating the need for separate dedicated interfaces for each protocol type

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The bus architecture dynamically switches between two operational modes: in the first mode, clock and data are transmitted on separate lines for two-wire devices; in the second mode, clock pulses are embedded within the data line for one-wire devices. This dynamic reconfiguration allows the same physical infrastructure to adapt to different communication requirements without adding permanent complexity

Inventive Principle:
Principle #15Dynamics

2Reliability

If traditional separate clock and data line architecture is used, then communication reliability for two-wire devices is maintained, but the number of physical pins and connection complexity increase

Engineering Contradiction:
Improvecommunication reliabilityVSAvoidnumber of physical pins
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The invention merges the clock signal and data signal into a single data line by embedding clock pulses within the data transmissions. This combining of previously separate signals reduces the physical pin count from two dedicated lines to one shared line, while maintaining communication reliability through the use of sequence start conditions that indicate whether clock pulses are embedded

Inventive Principle:
Principle #5Merging (Combining)

3Quantity of substance

If clock pulses are embedded in the data line, then the number of I/O pins is reduced, but timing synchronization and signal interpretation become more complex

Engineering Contradiction:
Improvenumber of I/O pinsVSAvoidtiming synchronization complexity
Core Design Contradiction:
Quantity of substanceVSDifficulty of detecting and measuring

Solution Approach 1:

Before actual data transmission begins, the system transmits a sequence start condition that预先 indicates whether clock pulses will be embedded in the upcoming data transmissions. This preliminary signaling allows receiving devices to prepare their timing synchronization mechanisms in advance, reducing the complexity of real-time signal interpretation

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The sequence start condition acts as a feedback mechanism that informs slave devices about the upcoming transmission mode. This feedback allows devices to automatically adjust their timing and sampling strategies based on the indicated mode, simplifying the overall synchronization process despite the embedded clock architecture

Inventive Principle:
Principle #23Feedback

4Quantity of substance

If a unified serial bus is used for both one-wire and two-wire communication, then I/O pin count is reduced, but communication protocol complexity increases

Engineering Contradiction:
ImproveI/O pin countVSAvoidcommunication protocol complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The communication protocol is segmented into distinct transmission modes, each with clearly defined characteristics. The sequence start condition divides the communication flow into identifiable segments, allowing devices to process each segment according to its specific requirements without needing to handle all possible variations continuously

Inventive Principle:
Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enables efficient data transmission over a single wire, reducing bus latency and supporting high-priority messages, while minimizing the number of physical input/output pins required, thus enhancing communication efficiency and reducing complexity in multi-radio, multi-application systems.

Implementation Method 1

The transmitter may be configured to transmit data over the bus as a sequence of pulses within symbol slots. In the second mode of operation a transmission period of a first symbol slot may be stretched to prevent the I2C-compatible devices from changing into an unpredictable state as a result of a transition from a first pulse to a second pulse.

Methodology Applied
Scientific EffectPulse-width modulation: Phase Modulation

Data Source

PatentEP3847554B1Mixed-mode radio frequency front-end interface
Publication Date: 2022.01.26 QUALCOMM INC
  • EP3847554B1 patent drawingFigure 1
  • EP3847554B1 patent drawingFigure 2
  • EP3847554B1 patent drawingFigure 3

AI summary

The described systems, apparatus and methods enable communication between devices that use a single-wire link and devices that use a multi-wire link. One method performed at a master device includes transmitting a sequence start condition over a data wire of a serial bus, the sequence start condition indicating whether clock pulses are to be provided in a clock signal on a clock wire of the serial bus concurrently with a transaction initiated by the sequence start condition, transmitting a first datagram over the serial bus when the sequence start condition indicates that the clock pulses are to be concurrently provided in the clock signal, and transmitting a second datagram over the serial bus when the sequence start condition indicates that no clock pulses are to be concurrently provided in the clock signal. The second datagram may be transmitted in a data signal with embedded timing information.