Full-Duplex SPI Arbitration Lines for Bidirectional Controller Communication
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Solution Overview
Problem
Existing SPI communication in automotive electronic controllers is limited by transmission direction, communication flexibility, and load capacity due to its master-slave communication structure, where only the master can initiate communication.
Innovation Solution
An arbitration line-based full-duplex SPI communication method that allows both master and slave devices to initiate communication by using additional arbitration lines to determine the communication state and synchronize data transmission, dividing messages into header and body data, and optionally using ACK for important messages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional master-slave SPI communication is used, then hardware structure remains simple, but transmission direction is limited and communication flexibility is reduced
Solution Approach 1:
The communication protocol is segmented into distinct layers: arbitration layer (using arbitration lines CLR/CLRb) and data transmission layer (using MOSI/MISO). This segmentation allows the hardware to remain relatively simple while the arbitration mechanism enables flexible bidirectional communication by separating the control function from the data transfer function.
Solution Approach 2:
Arbitration lines (CLR and CLRb) are introduced as intermediary control signals between master and slave devices. These intermediary lines enable either device to initiate communication by asserting their respective arbitration signal, thus providing full-duplex capability without requiring complex reconfiguration of the basic SPI hardware structure.
2Productivity
If master-only initiation is used, then communication protocol remains simple, but load capacity is limited
Solution Approach 1:
The communication system dynamically switches between master-initiated and slave-initiated modes based on real-time needs. The slave device can dynamically become the initiator by asserting CLRb when it has data to send, allowing the system to adapt to varying communication loads and improve overall productivity.
Solution Approach 2:
The arbitration mechanism uses periodic arbitration signal assertions (CLR for master, CLRb for slave) to gain communication initiation rights. This periodic arbitration approach allows multiple devices to compete for bus access in a structured manner, increasing load capacity while maintaining protocol simplicity.
3Adaptability or versatility
If arbitration lines are added for bidirectional communication, then transmission direction is improved, but hardware complexity increases
Solution Approach 1:
The arbitration functionality is merged with the existing SPI hardware framework. The arbitration lines CLR and CLRb are integrated into the same signal routing infrastructure as the data lines, allowing bidirectional communication to be achieved by combining simple logic functions with the existing hardware rather than adding completely separate communication channels.
Data Source
AI summary
The present disclosure provides an arbitration line-based full-duplex SPI communication method. Said method comprises: a communication requester detecting a first arbitration line corresponding to the communication requester and a second arbitration line corresponding to a communication responder, and if both the first arbitration line and the second arbitration line are at a low potential, pulling up the potential of the first arbitration line; when the communication responder detects the first arbitration line is at a high potential, pulling up the potential of the second arbitration line; when the communication requester detects the second arbitration line is at a high potential, determining the communication responder is in a communicating state; the communication requester and the communication responder sending message header data and message text data to each other. The present disclosure solves the problem of the transmission direction and communication flexibility being limited in existing SPI communication.