Steering Column Switching Assembly Microcontroller I/O Reduction
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Solution Overview
Problem
Existing motor vehicle steering column control assemblies are complex and costly due to the need for numerous inputs and outputs to manage multiple switching modules, leading to inefficiencies and increased wiring requirements.
Innovation Solution
A simplified switching assembly with a microcontroller that uses shared digital inputs and outputs to deduce switching states from sequences of digital signals, allowing for standardized connections and reduced wiring, and incorporates an identifier for module recognition, enabling efficient management of multiple functions with fewer connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional switching assemblies use separate inputs and outputs for each switch module, then each switch can be independently controlled, but the number of microcontroller I/O pins and wiring increases significantly
Solution Approach 1:
Multiple switch modules are electrically connected in parallel between a single digital output of the microcontroller and a single digital input. This merging of connections allows the microcontroller to control multiple switches through shared wiring, dramatically reducing the number of I/O pins required from potentially dozens to just one or a few.
Solution Approach 2:
The microcontroller activates digital outputs in a periodic scanning sequence, activating one output at a time in rotation. By timing the activation of each output and monitoring the corresponding input state during each activation period, the system determines which switches are closed without requiring dedicated I/O pins for each switch, thus reducing wiring complexity while maintaining independent control capability.
2Adaptability or versatility
If multiple switching modules are connected to the steering column top, then more functions can be controlled, but the wiring requirements and system cost increase
Solution Approach 1:
The switching assembly uses standardized connector designs that can accommodate different types of switching modules (e.g., audio controls, telephone controls, cruise control). The same physical connector and wiring topology serves multiple functional purposes, allowing a single wiring harness to support various control functions without requiring additional dedicated wiring for each function type.
Solution Approach 2:
Multiple switching modules share common power supply connections and ground connections through the parallel configuration. Instead of providing separate power and ground wires for each module, the system merges these connections into shared common lines that serve all modules simultaneously, significantly reducing the total quantity of wiring materials required.
3Difficulty of detecting and measuring
If each switch module has dedicated connections to the microcontroller, then signal routing is simple, but the system becomes costly and complex
Solution Approach 1:
The microcontroller pre-establishes a known scanning sequence for activating digital outputs and monitors corresponding input states in a predetermined time sequence. This preliminary structured approach to signal activation and detection creates a predictable, systematic method for determining switch states, making the signal routing logic manageable despite the shared physical connections.
Solution Approach 2:
The system uses feedback from the digital input to determine which switches are closed. When a digital output is activated, the microcontroller monitors the corresponding digital input state to detect which switches in that group are closed. This feedback mechanism provides clear signal routing information without requiring dedicated bidirectional connections for each switch, maintaining routing clarity while reducing system complexity.
Data Source
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AI summary
The invention relates to a switching assembly for the top portion of an automobile steering column that comprises: - a base substrate (5) having a plurality of locations (E1, E2, E3, E4) connectable to switching module (7) connectors, each switching module (7) having at least one switch (15) capable of going into switching mode on the basis of the control position used by a user; - a microcontroller (17) for managing the switching assembly, characterized in that: each location (E1, E2, E3, E4) includes at least two digital inputs connected to identical digital outputs (s1, s2) of said microcontroller (17) and at least two digital outputs connected to identical digital inputs (e1, e2, e3, e4) of said microcontroller (17); and said microcontroller (17) is configured to be able to deduce, from a sequence of digital signals sent by said microcontroller (17) to each location and digital signals received by said microcontroller (17) from each location (E1, E2, E3, E4) and corresponding to electric signals having transited through a switching module connected to a location, at least one switching mode of a switch of said switching module. The invention also relates to a corresponding control assembly and control method.