Serial Bus Slave Circuit Identifier Conflict Resolution

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Solution Overview

Problem

In open-drain or open-collector bus communication systems, identifying and addressing multiple slave circuits simultaneously is challenging, especially when they share the same address, leading to communication conflicts and interpretation issues.

Innovation Solution

A method where two slave circuits simultaneously transmit their identifiers and their inverses over a serial bus, allowing each to determine their order of communication, with a master circuit initiating the process using a specific control signal and common address, enabling the master to distinguish between them.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple slave circuits share the same address on an open-drain bus, then the system can support more slave circuits with simplified addressing, but communication conflicts occur when multiple slaves respond simultaneously

Engineering Contradiction:

Improveability to support multiple slave circuitsVSAvoidcommunication reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The identifier transmission is segmented into multiple phases: first transmitting the identifier bits, then transmitting the inverse bits. This segmentation allows the master circuit to detect conflicts in the first phase and control the retransmission in the second phase, resolving simultaneous response conflicts while supporting multiple slaves with the same address.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system performs preliminary identification by having slave circuits transmit their identifiers before actual data communication. The master circuit detects which slaves are present and prepares appropriate responses in advance, preventing communication conflicts during subsequent data transmission phases.

Inventive Principle:

Principle #10Preliminary action

2Ease of operation

If the master circuit sends addresses to identify slave circuits, then individual slave recognition is enabled, but the master must know all slave addresses in advance which limits system flexibility

Engineering Contradiction:

Improveslave recognition capabilityVSAvoidsystem flexibility

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

Slave circuits self-identify by autonomously transmitting their identifiers when addressed. Instead of the master needing to know all addresses beforehand, the slaves actively present their identities in response to a broadcast address, enabling dynamic slave discovery and adding to system flexibility while maintaining ease of recognition.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system implements feedback mechanisms where slave circuits respond to master queries by transmitting their identifiers. The master receives this feedback, identifies which slaves are present, and adjusts subsequent communication accordingly. This feedback loop enables flexible slave discovery without requiring pre-configured address knowledge.

Inventive Principle:

Principle #23Feedback

3Speed

If slave circuits transmit identifiers simultaneously, then identification speed is improved, but the resulting conflicts make transmission interpretation impossible

Engineering Contradiction:

Improveidentification speedVSAvoidtransmission interpretability

Core Design Contradiction:

SpeedVSLoss of information

Solution Approach 1:

The system converts the harmful effect of simultaneous transmission conflicts into a beneficial identification mechanism. When conflicts occur during identifier transmission, the master circuit uses the conflict detection to trigger specific responses from individual slaves, transforming the problematic simultaneous transmission into a structured identification sequence that enables both speed and interpretability.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS8892798B2Identification, by a master circuit, of two slave circuits connected to a same bus

Publication Date: 2014.11.18 STMICROELECTRONICS (ROUSSET) SAS

AI summary

A method of communication between a master circuit and two slave circuits over a serial bus wherein: the two slave circuits simultaneously transmit their associated identifiers; the two slave circuits simultaneously transmit the inverse of these identifiers; and each slave circuit exploits the combinations present on the bus to determine an order of communication between the two circuits.