Bridge Circuit Isolation for Faulty-Master Write Completion

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Solution Overview

Problem

In safety-critical applications, a faulty master in a data processing system can cause system memory corruption or hang due to its inability to reliably complete outstanding transactions, posing a risk to overall system reliability.

Innovation Solution

A bridge circuit within the system interconnect tracks issued write commands and data, isolating the faulty master and using a command buffer to complete outstanding transactions without relying on the faulty master, ensuring all commands and data are processed without protocol violations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the faulty master is relied on to complete outstanding transactions, then the system can operate uninterrupted, but system memory corruption or hang may occur due to protocol violations

Engineering Contradiction:
Improvesystem reliabilityVSAvoidsystem memory corruption or hang
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The bridge circuit extracts and isolates the faulty master from the system interconnect, separating the harmful faulty master from the healthy system components. This allows the system to complete outstanding transactions through the bridge's command buffer without relying on the faulty master, preventing memory corruption while maintaining operational continuity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The bridge circuit acts as an intermediary between the faulty master and the system interconnect. It receives commands from the faulty master, stores them in its command buffer, and completes them without further involvement from the faulty master. This intermediary mechanism prevents protocol violations from reaching the system memory while ensuring transaction completion.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If the faulty master is isolated immediately, then protocol violations are prevented, but outstanding transactions cannot be completed

Engineering Contradiction:
Improveprotocol violationsVSAvoidtransaction completion
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The bridge circuit performs preliminary action by capturing and storing outstanding transactions in its command buffer before isolating the faulty master. This preliminary storage ensures that transactions are preserved and can be completed later through the bridge's internal mechanisms, maintaining both transaction completion and protocol integrity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The bridge circuit maintains continuity of useful action by completing outstanding transactions through its command buffer after isolating the faulty master. The bridge continues to process and complete transactions that were initiated by the faulty master, ensuring uninterrupted system operation without relying on the faulty master.

Inventive Principle:
Principle #20Continuity of useful action

3Reliability

If a command buffer is introduced to track outstanding transactions, then transaction completion is ensured, but device complexity increases

Engineering Contradiction:
Improvetransaction completionVSAvoidbridge circuit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The bridge circuit performs multiple functions: it acts as an intermediary, maintains a command buffer for tracking transactions, isolates faulty masters, and completes outstanding transactions. By consolidating these diverse functions into a single bridge component, the design achieves reliable transaction completion without proportionally increasing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4047479B1Safe-stating a system interconnect within a data processing system
Publication Date: 2025.10.29 NXP BV
  • EP4047479B1 patent drawingFigure 1
  • EP4047479B1 patent drawingFigure 2
  • EP4047479B1 patent drawingFigure 3

AI summary

A data processing system includes a system interconnect, a first master, and a bridge circuit. The bridge circuit is coupled between the first master and the system interconnect. The bridge circuit is configured to, in response to occurrence of an error in the first master, isolate the first master from the system interconnect, wherein the isolating by the bridge circuit is performed while the first master has one or more outstanding issued write commands to the system interconnect which have not been completed. The bridge circuit is further configured to, after isolating the first master from the system interconnect, complete the one or more outstanding issued write commands while the first master remains isolated from the system interconnect.