Variable Length Response Messages in Master-Slave Communications
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Solution Overview
Problem
In master-slave communications, slave devices respond with fixed-length messages, leading to irrelevant data and increased bus traffic, which slows down data throughput.
Innovation Solution
Implementing a variable length response message system where the slave device determines the message length and communicates it to the master device, ensuring only necessary data is transmitted, with the master device requesting and receiving only the relevant parts of the response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fixed-length response messages are used in master-slave communications, then the communication protocol is simple and easy to implement, but unnecessary bus traffic increases and data throughput decreases
Solution Approach 1:
The patent applies dynamics by making the response message length variable rather than fixed. The slave device determines the actual length of data to transmit and communicates this length to the master device, allowing the message length to adapt dynamically to the actual data requirements, thus eliminating transmission of unnecessary data and improving throughput while reducing bus traffic.
Solution Approach 2:
The patent changes the parameter of message length from a fixed constant to a variable parameter. The slave device calculates the number of data items to report and sets the message length accordingly, then communicates this length parameter to the master device before transmitting the actual data, enabling efficient adaptation to varying data conditions.
2Device complexity
If fixed-length response messages are used, then the communication protocol is simple, but irrelevant data is transmitted causing increased bus traffic
Solution Approach 1:
The patent applies preliminary action by having the slave device calculate and communicate the message length before actually transmitting the data payload. This preliminary step allows the master device to allocate appropriate buffer space and process only the necessary amount of data, avoiding wasted bus traffic on irrelevant data while maintaining protocol simplicity through a straightforward two-step process.
3Productivity
If variable length response messages are implemented, then data throughput is improved by eliminating irrelevant data, but the communication protocol becomes more complex
Solution Approach 1:
The patent applies segmentation by dividing the response message into two distinct parts: a length indicator field that specifies the message length, and a data payload field that contains the actual information. This segmentation allows the protocol to handle variable-length messages efficiently by processing the length information separately from the data, improving throughput without excessive complexity increase.
Data Source
AI summary
A method for sending a variable length response message in a master-slave communication system begins by issuing a command from a master device to a slave device. A response message is generated by the slave device. The length of the response message is determined by the slave device and is communicated from the slave device to the master device. The master device requests the rest of the response message from the slave device, and the slave device then sends the rest of the response message to the master device.