Bus Semaphore Timeout Control for Multi-Master Resource Sharing
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Solution Overview
Problem
Existing systems lack effective management to prevent function blocks from waiting excessively for resource access, leading to errors and performance degradation.
Innovation Solution
A device and method utilizing timers and a controller to manage semaphore allocation among multiple master devices, ensuring timely termination of access requests and preventing excessive waiting by providing messages when expiration intervals are reached.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If semaphore allocation is managed without time limits, then resource access is simplified, but function blocks may wait excessively causing errors and performance degradation
Solution Approach 1:
The patent applies preliminary action by setting predetermined expiration intervals for semaphore allocation before the waiting process begins. Each master device is assigned a time limit in advance, and the controller monitors these time limits proactively. This prevents excessive waiting by establishing time constraints beforehand, ensuring that function blocks do not wait indefinitely for resource access, thereby maintaining system reliability while preserving ease of operation through automated time management.
2Loss of time
If expiration intervals are set for semaphore allocation, then waiting time is controlled, but system complexity increases due to multiple timers and monitoring mechanisms
Solution Approach 1:
The patent merges the timer functions by implementing a single controller that manages multiple expiration intervals simultaneously. Instead of requiring separate timer hardware for each master device, the controller integrates the timing and monitoring functions into one centralized unit. This reduces device complexity while still effectively controlling waiting times for all master devices, as the controller can track and enforce expiration intervals for multiple semaphores using a unified timing mechanism.
3Reliability
If messages are sent to master devices when expiration intervals are reached, then excessive waiting is prevented, but communication overhead increases via bus transactions
Solution Approach 1:
The patent implements feedback by having the controller monitor expiration intervals and send messages back to master devices only when necessary—that is, when an expiration interval is reached and the semaphore has not been allocated. This selective feedback mechanism prevents excessive bus communication by transmitting messages only in error conditions, rather than continuously or preemptively. The feedback loop maintains reliability through error prevention while minimizing energy consumption by activating bus communication only when needed to inform master devices of timeout conditions.
Data Source
AI summary
The device described herein, which provides an interface between a plurality of master devices and a slave device, includes: a first timer configured to begin timing when a first access request is received from a first master device via a bus, and to be reset when a semaphore is allocated to the first master device; a second timer configured to begin timing when a second access request is received from a second master device via the bus, and to be reset when a semaphore is allocated to the second master device; and a controller configured to provide a first message to the first master device via the bus when a first expiration interval is measured by the first timer.