Hardware Semaphore Logic Circuit for Multi-Master Access Control
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Solution Overview
Problem
Implementing a semaphore for controlling a single slave device through a shared interface in mobile devices is resource-intensive and complex, particularly in real-time operating systems, where fixed waiting times are difficult to secure for fast response times.
Innovation Solution
A system on chip with a hardware-based semaphore logic circuit that detects access requests from multiple masters and assigns a semaphore for a desired operational period, using atomic sequencers and a semaphore controller to manage access and release of the semaphore, allowing efficient sharing of a slave device without software interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a semaphore is implemented in software to control a single slave device through a shared interface, then the system can manage multi-master access, but software complexity increases and response time becomes fixed and slower
Solution Approach 1:
The patent replaces the software-based semaphore mechanism with a hardware-based semaphore logic circuit. This hardware circuit automatically manages semaphore assignment and release through electronic signals, eliminating the need for complex software scheduling and interrupt handling. The hardware implementation provides deterministic access control while reducing software complexity.
Solution Approach 2:
The patent introduces a dedicated semaphore logic circuit as an intermediary component between multiple masters and the shared interface. This intermediate hardware module handles all semaphore-related operations (detection, assignment, release) centrally, allowing masters to access the interface without direct software intervention for semaphore management.
2Adaptability or versatility
If a software-based semaphore is used for real-time operating system scheduling, then multi-master coordination is achieved, but response time is fixed and fast response becomes difficult to secure
Solution Approach 1:
The patent replaces software-based timing and scheduling mechanisms with hardware-based semaphore logic that operates in real-time. The hardware circuit responds to access requests immediately through electronic signal propagation, providing deterministic and fast response times that are not constrained by software execution cycles or interrupt latency.
Solution Approach 2:
The hardware semaphore logic circuit continuously monitors access requests and is ready to assign semaphores immediately when needed. The circuit maintains semaphore state information in hardware registers and can transition states instantly, eliminating the need for software polling or waiting for scheduled execution windows.
3Ease of operation
If software resources are allocated for semaphore implementation, then interface sharing is controlled, but resource consumption increases
Solution Approach 1:
The patent replaces software resource consumption with hardware resource consumption. The semaphore logic circuit uses dedicated hardware components (logic gates, flip-flops, multiplexers) that operate continuously with minimal power consumption compared to software execution. The hardware implementation eliminates the need for CPU cycles, memory access, and instruction execution associated with software-based semaphore management.
Data Source
AI summary
A system on chip, semiconductor device, and/or method are provided that include a plurality of masters, an interface, and a semaphore unit. The interface interfaces the plurality of masters with a slave device. The semaphore unit detects requests of the plurality of masters, controlling the salve device, about an access to the interface and assigns a semaphore about each of the plurality of masters by a specific operation unit according to the detection result.