Single USB Controller Simulating Multiple Virtual Devices
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Solution Overview
Problem
Conventional USB devices require multiple USB device controller chips and hubs to manage multiple devices, leading to complex hardware implementations and limited flexibility in device connections.
Innovation Solution
A USB device with a logic device and analog switch that generates fixed address signals to simulate multiple virtual USB devices and hubs, using a single USB device controller and microcontroller unit to manage communication with host computers and external devices via RF signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple USB device controller chips are used to manage multiple USB devices, then device management capability is improved, but hardware complexity increases
Solution Approach 1:
The patent applies multi-functionality by enabling a single USB device controller to perform multiple functions: it controls the host computer, manages external devices, and simulates virtual USB devices simultaneously. The controller chip executes different firmware programs to switch between these roles, eliminating the need for separate controller chips for each function and thereby reducing hardware complexity while maintaining versatile device management capability
Solution Approach 2:
The patent merges multiple USB device controller functions into a single controller chip. By combining the host computer control function, external device management function, and virtual USB device simulation function into one unified controller, the system achieves multiple device management capabilities without proportionally increasing hardware complexity, directly resolving the technical contradiction
2Adaptability or versatility
If a USB hub is used to simulate multiple downstream USB ports, then connection flexibility is improved, but device complexity increases
Solution Approach 1:
The patent makes the USB device controller multi-functional by enabling it to simulate multiple downstream USB ports through virtual USB device simulation. The single controller can dynamically switch between different virtual device modes, providing connection flexibility equivalent to a USB hub without requiring the additional hardware complexity of a separate hub device
Solution Approach 2:
The patent combines the USB hub functionality with the USB device controller into a single integrated unit. The controller chip performs both direct device control and virtual hub functions, merging what would traditionally require separate components into one device, thereby improving connection flexibility while controlling device complexity
3Device complexity
If one USB device controller is used to simulate multiple virtual USB devices, then hardware simplicity is improved, but address management complexity increases
Solution Approach 1:
The patent introduces an address translation mechanism as an intermediary layer between the single physical USB device controller and multiple virtual USB devices. The controller maintains a mapping between virtual device addresses and the single physical address, automatically translating address fields in USB packets. This intermediary address management system hides the complexity from the hardware level while enabling multiple virtual devices to be managed through one simple controller
Solution Approach 2:
The patent creates virtual copies of USB device addresses and identifiers. Instead of requiring multiple physical devices with unique hardware addresses, the system generates virtual address copies that map to the single physical controller. This copying approach allows the controller to present multiple distinct address identities to the system while maintaining hardware simplicity at the physical level
Data Source
AI summary
A USB device using one USB device controller to simulate multiple virtual USB devices with a virtual USB hub is described. The USB device controller is assigned a USB address and communicates with the USB host under the control of an MCU and its firmware. The USB device also includes a CPLD (or FPGA or ASIC) and an analog switch for filtering the USB packets from the host and replacing the address in the packet by a fixed address before sending the packet to the USB device controller. The address in the original packet is stored in the CPLD and accessible by the MCU. The MCU controls the USB device controller to simulate one or more USB hubs and multiple USB devices.