In-Frame Response Serial Data Communication for Bus Nodes
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Solution Overview
Problem
In serial data communication, existing concepts face inefficiencies due to the temporal offset in next-frame response structures, where the response to a command is only transferred in a succeeding frame, leading to undesired delays in applications requiring simultaneous data transfer.
Innovation Solution
The implementation of an in-frame response (IFR) method where a bus node receives a first frame, performs a read operation based on its header data, generates a second frame with payload data, and transmits it simultaneously with the first frame, allowing for immediate execution of read operations and embedded write commands within the same time window.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a next-frame response structure is used, then data transfer simplicity is maintained, but data transfer speed and responsiveness deteriorate due to temporal offsets
Solution Approach 1:
The communication protocol is segmented into distinct frame types (request frames and response frames) with specific bit patterns. Request frames use a first bit pattern indicating a read command, while response frames use a second bit pattern indicating a data response. This segmentation allows the system to differentiate between request and response operations, enabling faster response times without confusing the communication protocol.
Solution Approach 2:
The slave device performs the read operation immediately upon receiving the request frame header, before the entire request frame is fully transmitted. This preliminary action allows the slave to prepare response data in advance, reducing the temporal offset between request and response, and thereby improving data transfer speed while maintaining protocol simplicity.
2Productivity
If simultaneous data transfer in both directions is implemented, then communication efficiency improves, but timing synchronization becomes more difficult
Solution Approach 1:
The system implements feedback through response frames that confirm successful data retrieval. The slave device sends response frames containing read data back to the master device within the same time window, providing immediate feedback on the status of the read operation. This feedback mechanism enables the master to verify successful communication without additional timing delays.
Solution Approach 2:
The communication operates in periodic time windows where each window contains a request frame transmitted from master to slave and a corresponding response frame transmitted from slave to master. This periodic structure with regular time windows simplifies synchronization by establishing predictable timing patterns, reducing the loss of time associated with timing coordination.
3Loss of time
If in-frame response is implemented, then response time is reduced, but risk of data corruption increases due to concurrent frame transmission
Solution Approach 1:
The system uses separate data channels (MOSI and MISO) as intermediaries for bidirectional communication. The request frame is transmitted through MOSI while the response frame is transmitted through MISO, allowing concurrent transmission without interference. This intermediary channel separation ensures data integrity by preventing signal collision while maintaining reduced response times through simultaneous transmission.
Solution Approach 2:
The protocol incorporates checksum fields and error detection mechanisms in advance of data transmission. By preparing error checking capabilities beforehand, the system can detect and handle potential data corruption from concurrent transmission without compromising overall reliability, thus maintaining both reduced response time and data integrity.
Data Source
AI summary
A method for a bus node includes receiving a first frame via a first data channel. The first frame includes a first header field having first header data and a first payload field having first payload data. The method further includes implementing a read operation at a read address determined by the first header data, and generating a second frame containing at least a second payload field having second payload data. The latter are based on the data read when implementing the read operation. The method further includes transmitting the second frame via a second data channel simultaneously with receiving the first frame via the first data channel, and implementing a write operation on the basis of the first payload data.