RS-485 Circuit Automatic State Switching via Signal Edge Detection
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Solution Overview
Problem
The RS-485 communication standard requires additional I/O terminals and software codes to switch between data sending and receiving states, increasing software development workload, wasting human resources and I/O resources in processing modules.
Innovation Solution
An RS-485 circuit with a start detector, control module, and counter that automatically determines data transmission direction and time, eliminating the need for additional I/O ports and software codes by generating switching signals based on signal edges and counting information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additional I/O terminals and software codes are added to the processing module to control state switching, then the RS-485 interface can switch between sending and receiving states, but the workload of software development increases, human resources for research and development are wasted, and I/O resources of the processing module are wasted
Solution Approach 1:
The RS-485 interface chip automatically detects the data signal edge and generates the start signal without external intervention. The counter automatically counts the data transmission duration and generates the switching signal when expiration occurs, making the system self-controlling and eliminating the need for additional I/O terminals and software codes
Solution Approach 2:
The patent replaces the software-based control mechanism with a hardware-based automatic control mechanism. The start detector and counter are implemented as hardware circuits that automatically detect signal edges and control state switching, substituting the mechanical/software approach with an automated hardware system
2Adaptability or versatility
If additional I/O terminals and software codes are added to the processing module to control state switching, then the RS-485 interface can switch between sending and receiving states, but I/O resources of the processing module are wasted
Solution Approach 1:
The patent extracts the state switching control function from the processing module's I/O terminals and software codes, implementing it independently within the RS-485 interface chip through the start detector and counter, thereby freeing up I/O resources in the processing module
Solution Approach 2:
The RS-485 interface chip performs self-control by automatically detecting data signal edges and generating switching signals through its internal counter, eliminating the need to consume I/O terminals and software resources from the processing module
Data Source
AI summary
Disclosed is an RS-485 circuit, which includes an RS-485 interface chip, a start detector, a control module and a counter. The RS-485 interface chip includes a data input terminal and an enable terminal, wherein the data input terminal is configured to receive a data signal, the enable terminal is configured to receive a start signal or a switching signal to make the RS-485 interface chip in a data transmitting state or a data receiving state. The start detector is configured to detect a first signal edge of the data signal to generate the start signal to the enable terminal. After detecting the first signal edge of the data signal, the control module outputs first counting information. The counter is configured to count based on the first counting information, and output the switching signal to the enable terminal when the counter expires.