Multi-drop Serial Bus Location Detection via Voltage Divider
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Solution Overview
Problem
Existing systems fail to detect the physical location of 'dumb' devices on a serial bus without adding mechanical or electrical complexity and cost, as these devices lack the necessary microcontroller or circuitry for self-location determination.
Innovation Solution
A resistive voltage divider network is integrated into the serial bus, coupled with an analog-to-digital converter, allowing the master device to electronically determine the physical position of slave devices by varying signal voltages based on their location, without requiring additional conductors or location detection circuitry in the slave devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mechanical keying or additional wiring is used to detect physical location of dumb devices, then location detection capability is improved, but mechanical and electrical complexity and cost increase
Solution Approach 1:
The existing data line is made to serve dual purposes: both data transmission and location detection. By utilizing the same conductor for both functions, the patent eliminates the need for separate location detection wiring while maintaining the ability to detect physical positions of devices on the bus.
Solution Approach 2:
The patent introduces a master device with location detection circuitry that acts as an intermediary to determine device positions. Instead of requiring each dumb device to have location detection capability, the master device queries along the bus and detects voltage levels at different positions, serving as a mediator that enables location detection without burdening individual slave devices.
2Measurement precision
If additional wiring is added to detect device locations, then location detection accuracy is improved, but the number of conductors increases
Solution Approach 1:
The data line is made multi-functional, serving both as the communication conduit for data transmission and as the sensing medium for location detection. This eliminates the need for separate conductors dedicated to location detection, maintaining accurate position identification while using existing wiring infrastructure.
3Adaptability or versatility
If location detection circuitry is added to slave devices, then self-location determination capability is improved, but device complexity and cost increase
Solution Approach 1:
The master device serves as an intermediary that performs location detection on behalf of the system. Instead of equipping each slave device with location detection circuitry, the master device initiates queries and detects voltage levels at different positions along the bus, enabling the system to determine device locations without adding complexity to individual slave devices.
Solution Approach 2:
The patent enables the existing bus infrastructure to serve its own location detection needs through voltage level analysis. By querying the bus and measuring voltage at different positions, the system utilizes its existing components to determine device locations without requiring additional intelligent circuitry in each slave device.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate electronic differentiation of device locations along the serial bus, ensuring correct positioning without increasing the number of wires or adding complexity, thus preventing issues like ink mixing in printing systems.
Implementation Method 1
A resistive voltage divider network is integrated into the serial bus, coupled with an analog-to-digital converter, allowing the master device to electronically determine the physical position of slave devices by varying signal voltages based on their location
Data Source
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AI summary
A slave device to be connected to a master device by a multi-drop serial bus having a data line comprises a memory location containing a bit sequence including at least one zero bit, and circuitry that, in response to receiving a read command from the master device, transmits the bit sequence on the data line.