USB Multiplexing Single-Wire Interface Unit Pin Reduction
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Solution Overview
Problem
Existing inter-chip communication interfaces, such as SPI, serial port, and IIC, fail to achieve high communication rates while occupying fewer pins and lacking data integrity and communication reliability mechanisms.
Innovation Solution
A USB multiplexing single-wire interface unit that utilizes a D+ pin and a D− pin, with a control bit register and a USB controller incorporating EOP and bus reset detection modules, allowing for mode switching between USB and single-wire interface modes to enable high-speed communication with reduced pin usage and integrated data integrity and reliability mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If USB mode is used for inter-chip communication, then communication rate is improved (up to 12 Mbps), but number of occupied pins increases (uses D+ and D− pins)
Solution Approach 1:
The USB controller is designed to support both USB mode and single-wire interface mode, allowing the same hardware resources (USB controller, D+ pin) to perform multiple functions. The control bit register enables dynamic switching between modes, making the interface universal and adaptable to different communication requirements.
Solution Approach 2:
The interface dynamically switches between USB mode and single-wire interface mode based on communication requirements. The mode identification in the control bit register allows the system to adaptively select the appropriate operating mode, enabling flexible pin usage where D− pin can be controlled or left uncontrolled depending on the selected mode.
2Quantity of substance
If single-wire interface mode is used to save pins, then number of occupied pins is reduced (uses only D+ pin), but communication rate deteriorates (limited by single-wire protocol)
Solution Approach 1:
The USB controller serves dual purposes: it handles high-speed USB communication when two pins are available, and single-wire interface communication when pin conservation is prioritized. This multi-functionality resolves the contradiction by allowing the system to achieve both pin savings and high communication rates depending on the operational context.
Solution Approach 2:
The system changes operational parameters (mode identification in control bit register) to switch between USB mode and single-wire interface mode. This parameter change enables the interface to adapt its characteristics, allowing pin count and communication rate requirements to be balanced based on specific application needs.
3Device complexity
If simple physical layer interfaces (SPI, serial port, IIC) are used, then device complexity is reduced, but data integrity and communication reliability mechanisms are lacking
Solution Approach 1:
The patent merges the simplicity of single-wire interface with the reliability mechanisms of USB protocol. By integrating USB controller functionality into the single-wire interface mode, the system combines the low complexity of single-wire communication with the robust data integrity detection and communication reliability mechanisms of USB, including CRC and automatic retry capabilities.
Data Source
AI summary
An USB multiplexing single-wire interface unit comprises a D+ pin, a D− pin, a control bit register for USB and single-wire interface modes and a USB controller, the USB controller comprises an EOP detection module and a single-wire interface EOP detection module. The USB mode or the single-wire interface mode is selected according to mode identification of the control bit register for USB and single-wire interface modes, an output of the EOP detection module is selected as a USB EOP trigger signal in the USB mode, and an output of the single-wire interface EOP detection module is selected as a USB EOP trigger signal in the single-wire interface mode.