vECU Error-Out Signaling for Stuck-at-Fault Detection
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Solution Overview
Problem
Virtual electronic control units (vECUs) in a system on a chip (SoC) may experience faults, requiring fault recovery to prevent disruption to other vECUs, while maintaining a known and defined state during recovery.
Innovation Solution
A fault collection and control unit (FCCU) generates an error out (EOUT) signal using toggled or static signals on EOUT pins to indicate the vECU's state, allowing detection of stuck-at-faults and enabling fault recovery without redundant pins, and managing fault recovery through local or SoC resets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a vECU experiences a fault and requires fault recovery, then the vECU can be reset to a known state, but the EOUT pin may remain stuck at a fault indication even after successful recovery
Solution Approach 1:
The patent applies periodic action by toggling the EOUT signal at a defined frequency during normal operation. This periodic toggling allows the external device to detect whether the EOUT pin is functioning properly. If the pin is stuck at a fault indication after recovery, the absence of toggling reveals the stuck-at-fault condition, enabling detection without requiring redundant pins.
2Difficulty of detecting and measuring
If redundant pins are added to detect stuck-at-fault conditions, then fault detection capability is improved, but the number of pins and device complexity increases
Solution Approach 1:
The patent makes the EOUT pin multi-functional by using it for both normal fault indication and stuck-at-fault detection. During normal operation, the EOUT pin toggles to indicate operational status. During fault recovery, the same pin's lack of toggling indicates a stuck-at-fault condition. This eliminates the need for separate redundant detection pins, reducing device complexity while maintaining detection capability.
3Loss of information
If the EOUT signal is continuously toggled to indicate normal state, then the state indication is clear, but power consumption increases
Solution Approach 1:
The patent uses periodic toggling of the EOUT signal at a defined frequency during normal operation to provide clear state indication. The periodic nature allows external devices to detect the state through frequency analysis while enabling stuck-at-fault detection. During fault conditions, the toggling stops, providing clear fault indication without continuous power consumption during actual fault states.
Data Source
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AI summary
An error out (EOUT) controller of a system on a chip (SoC) for fault management generates a first EOUT signal which indicates a virtual electronic control unit (vECU) of the SoC comprising a plurality of vECU is in a first state. The first EOUT signal is output, where the first EOUT signal is toggled at a first toggle frequency. A fault signal which indicates the vECU having a fault is received. Based on receiving the fault signal, an EOUT circuit is selected from a plurality of EOUT circuits and the selected EOUT circuit generates a second EOUT signal which indicates the vECU is in a second state. The second EOUT signal is then output, where the second EOUT signal is a toggled at a second toggle frequency or is a static signal.