Master Slave Communication Arbitration for Polling Load Reduction

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

In communication systems with multiple slave devices, the master device experiences a significant load when periodically polling for state changes, leading to increased communication overhead and CPU load, as it cannot immediately receive state changes from sensors if the polling interval is too long or becomes excessively busy if too short.

Innovation Solution

Each slave device generates a request signal to initiate data transmission to the master device only when data is available, allowing the master device to selectively communicate with slaves as needed, using a request signal generation and arbitration mechanism to manage communication and reduce CPU load through DMA techniques.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the master device periodically polls slave devices to obtain state information, then the master device can monitor slave device states, but the communication load and CPU load increase significantly

Engineering Contradiction:

Improvestate monitoring capabilityVSAvoidcommunication load

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent inverts the traditional polling architecture by enabling slave devices to actively request communication with the master device when data needs transmission. Instead of the master device initiating periodic polls, slave devices generate request signals when their sensor data changes, fundamentally reversing who initiates the communication and reducing unnecessary polling overhead.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

Slave devices are empowered to self-manage their communication needs by autonomously generating request signals when data transmission is necessary. This self-service mechanism eliminates the need for continuous master device polling, as each slave device independently determines when communication with the master is required based on its own data state.

Inventive Principle:

Principle #25Self-service

2Productivity

If the polling interval is extended to reduce communication frequency, then CPU load decreases, but state change detection becomes delayed

Engineering Contradiction:

Improvecommunication efficiencyVSAvoidstate change detection delay

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The system implements feedback through request signals that slave devices generate when their data changes. This feedback mechanism ensures the master device is immediately notified of state changes without requiring frequent polling, as the slave device actively signals when communication is needed rather than waiting for the next poll cycle.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The communication system transitions from static periodic polling to dynamic event-driven communication. The polling interval becomes adaptive based on actual data changes, with communication frequency automatically adjusting to match the rate of state changes in slave devices, optimizing both responsiveness and efficiency.

Inventive Principle:

Principle #15Dynamics

3Speed

If multiple slave devices transmit data simultaneously to the master device, then communication responsiveness improves, but signal conflicts occur on shared lines

Engineering Contradiction:

Improvedata transmission responsivenessVSAvoidsignal conflict

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

The master device performs preliminary arbitration by selecting which slave device should transmit data next based on received request signals. This preliminary selection prevents signal conflicts by ensuring only one slave device transmits at a time on the shared communication lines, while still maintaining responsive communication through rapid arbitration and selection.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The master device acts as an intermediary that mediates between multiple slave devices seeking to transmit data. It receives request signals from multiple slaves, arbitrates their access to the shared communication lines, and sequentially grants transmission permission, preventing signal conflicts while maintaining system responsiveness.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS8719476B2Communication system, master device and slave device, and communication method, configured to handle plural concurrent requests

Publication Date: 2014.05.06 RICOH CO LTD

AI summary

A communication system includes a master device and slave devices. Each slave device includes a request signal generation part configured to, when data to transmit is generated, generate a request signal indicating a transmission request to a master device; and a transmission part configured to transmit the request signal to the master device. The master device includes a request signal reception part configured to receive the request signals from the slave devices; a selection part acting configured to select one of the slave devices according to the request signals received by the reception part; a transmission part configured to transmit a signal indicating to allow data transmission to the slave device selected by the selection part; and a data reception part configured to receive data from the selected slave device.