USB Pipe Arbitration Circuit Dynamic Allocation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
USB host controllers for embedded devices limit the number of peripheral devices that can be connected via pipes due to the fixed allocation of pipe control circuits, leading to insufficient resources for multiple external devices.
Innovation Solution
An arbitration circuit that stores available state information of pipe control circuits and dynamically allocates them based on usage, allowing sharing among multiple external devices by updating information after each data transfer of a predetermined communication size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pipe control circuits are fixedly allocated to each external device, then each device can access the resource exclusively, but the number of connectable peripheral devices is limited due to insufficient resources
Solution Approach 1:
The pipe control circuit transitions from a static fixed allocation to a dynamic shared allocation system. The arbitration circuit dynamically assigns the same pipe control circuit to different external devices based on availability, allowing the system to adapt to varying device connection requirements while maintaining exclusive access during active use.
Solution Approach 2:
A single pipe control circuit is designed to serve multiple external devices universally. The circuit can be allocated to different devices as needed, making one resource perform multiple functions for different devices sequentially, thereby increasing the number of connectable devices without adding more physical circuits.
2Adaptability or versatility
If multiple pipe control circuits are provided for each external device, then the number of connectable devices increases, but the circuit size increases
Solution Approach 1:
Multiple pipe control circuits are merged into a single shared resource that serves multiple external devices. The arbitration circuit combines the allocation logic for multiple devices into one circuit, reducing the total circuit size while maintaining the capability to serve multiple devices through time-multiplexed allocation.
Solution Approach 2:
Instead of providing physical copies of pipe control circuits for each device, the system uses a single circuit that is logically copied or replicated through arbitration. The same circuit instance is allocated to different devices sequentially, creating a virtual multiplication effect without physical duplication.
3Adaptability or versatility
If pipe control circuits are shared among multiple devices, then the number of connectable devices increases, but resource contention and allocation complexity increases
Solution Approach 1:
The arbitration circuit implements self-service allocation by automatically determining which external device should access the pipe control circuit based on predefined arbitration logic. The system serves itself by making allocation decisions without requiring complex external control, reducing allocation complexity while enabling multi-device connectivity.
Solution Approach 2:
The arbitration circuit uses feedback from device availability status and current allocation state to make dynamic allocation decisions. By continuously monitoring which devices are connected and which circuits are available, the system adjusts allocations in real-time, managing resource contention automatically without increasing overall system complexity.
Data Source
AI summary
Provided is an arbitration circuit included in a host controller that can be connected to a plurality of external devices via a plurality of pipe control circuits. The arbitration circuit includes an available state information storage unit that stores available state information. The available state information indicates an available state of the plurality of pipe control circuits and is updated by the pipe control circuit by a unit of data transfer of a predetermined communication size. The arbitration circuit further includes an arbitration unit that refers to the available state information storage unit, selects the arbitrary pipe control circuit from the available pipe control circuit, and allocates the selected pipe control circuit to the external device, while updating the available state information storage unit.