Electronic Control Unit Program Counter Error Detection
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Solution Overview
Problem
Conventional electronic control units with dual core lockstep systems face challenges in reducing power consumption while ensuring functional safety, as they require duplicate arithmetic circuits to operate effectively.
Innovation Solution
An electronic control unit is designed with a program counter, execution section, change section, storage control section, update section, comparison section, and error determination section, which uses a single dual system comprising a program counter and an expected value counter to detect errors during important processes, eliminating the need for duplicate arithmetic circuits and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dual core lockstep system with two arithmetic units is used to ensure functional safety, then reliability is improved, but power consumption increases
Solution Approach 1:
The patent divides the error detection function into segments: the dual core lockstep system is used only for the instruction fetch and decode phase (program counter management), while the execution phase uses a single arithmetic unit. This segmentation allows error detection without requiring two full arithmetic units to operate simultaneously, reducing power consumption while maintaining functional safety for critical operations.
Solution Approach 2:
The patent applies partial action by implementing the dual core lockstep mechanism only partially - specifically for program counter management and instruction address verification, but not for the entire arithmetic execution process. This partial application provides sufficient functional safety for error detection while avoiding the excessive power consumption of running two complete arithmetic units.
2Reliability
If two arithmetic units operate simultaneously to detect errors, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent segments the error detection function from the execution function. One arithmetic unit handles execution while a separate program counter management system (with its own comparison logic) handles error detection. This segmentation reduces device complexity by avoiding the need for two complete arithmetic units while maintaining error detection capability.
Solution Approach 2:
The patent introduces an intermediary comparison mechanism that monitors program counter values instead of requiring direct comparison of two arithmetic unit outputs. This intermediary approach simplifies the system architecture by using a dedicated comparison logic for error detection rather than duplicating entire arithmetic units.
Data Source
AI summary
In an electronic control unit, an important process includes several instructions that are successively executed and contain no branch instruction. Each of the instructions is stored in each of storage areas of memory according to an execution sequence. The storage areas are respectively assigned addresses that vary in increments of a specified value according to the execution sequence. The important process stores, in an expected value counter, a value of a program counter when control transitions to the important process. If a comparison result indicates a difference between the value of the program counter and a value of the expected value counter, an occurrence of an error is determined.