SPI Coupling Device for Daisy Chain Diagnostics
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Solution Overview
Problem
Daisy chain configurations in SPI bus systems face challenges with diagnostics and data communication, particularly in Programmable Logic Controllers (PLCs), due to limitations in existing slave devices that require additional functions like control and diagnostics, and the need for low-cost solutions adapted for daisy chain capabilities and standard microprocessor interfaces.
Innovation Solution
A coupling device is introduced that enables data exchange between slaves driven by different clocks, allowing for daisy chain capability and communication with masters, using a buffer to synchronize data transfer and incorporating a diagnostics unit for parallel operation, which can be powered with different supply voltages and isolated using known isolating means.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If standard microcontrollers are used in daisy chain configurations, then ease of operation and adaptability improve, but compatibility deteriorates due to the need for high internal clock rates and adaptation for daisy chain configurations
Solution Approach 1:
The patent introduces a coupling device as an intermediary component between the standard microcontroller and the daisy chain SPI bus. This coupling device includes a first slave interface that connects to the daisy chain and a second slave interface that connects to the microcontroller, enabling standard microcontrollers to operate in daisy chain configurations without requiring high internal clock rates or special adaptations, thus resolving the compatibility issue while maintaining adaptability
2Measurement precision
If diagnostic devices are implemented in daisy chain configurations, then measurement precision improves, but device complexity increases due to limited diagnostic capabilities and compatibility requirements
Solution Approach 1:
The coupling device is designed with universal functionality that serves multiple purposes: it acts as a bridge between different SPI interfaces, provides diagnostic capabilities through buffer access, and enables error detection. The device includes a buffer that stores data from the first slave, allowing the microcontroller to read and analyze this data for diagnostic purposes without adding complex dedicated diagnostic hardware to each slave device in the chain
3Adaptability or versatility
If buffering is implemented for data exchange between slaves driven by different clocks, then adaptability improves, but device complexity increases
Solution Approach 1:
The coupling device serves as a clock-mediated intermediary between slaves operating at different clock rates. The buffer within the coupling device temporarily stores data, allowing synchronization between different clock domains without requiring complex timing coordination logic in each slave device, thus enabling clock compatibility while keeping the buffering implementation relatively simple
Data Source
AI summary
The invention relates to coupling devices, a system comprising a coupling device and a method for use in a system comprising a coupling device.In accordance with an aspect of the invention, there is provided a coupling device for serial communication comprising a first slave having daisy chain capability and being configured to be coupled to and communicate with a first master, a second slave configured to be coupled to and communicate with a second master, and at least one buffer enabling data exchange between the first slave and the second slave, even if the first slave and the second slave are driven by different clocks.