Vehicular ECU Memory Rewriting Using External Storage Banks
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Solution Overview
Problem
Existing vehicle electronic control systems face challenges in rewriting software due to limitations in non-volatile memory configurations, where single-bank memory systems cannot rewrite software while traveling, and double-bank systems are inefficient in using memory capacity.
Innovation Solution
A microcomputer with a non-volatile memory having separate areas and a control unit with multiple cores executes a rewrite program, utilizing external storage to temporarily store reprogramming data, allowing software to be rewritten by separating the memory areas, effectively creating a pseudo-double-bank memory configuration even with single-bank or pseudo-single-bank memory setups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If single-bank non-volatile memory is used, then device complexity and cost are reduced, but software rewriting cannot be performed during vehicle travel
Solution Approach 1:
The patent introduces external storage as an intermediary component to enable software rewriting. The external storage temporarily holds reprogramming data during the update process, acting as a mediator between the single-bank non-volatile memory and the rewriting operation. This allows the system to achieve dual-bank functionality without modifying the internal memory structure, thus maintaining simplicity while enabling runtime software updates.
2Ease of operation
If double-bank non-volatile memory is used, then software rewriting during travel is enabled, but memory capacity utilization becomes inefficient
Solution Approach 1:
The external storage serves multiple functions: it acts as a temporary buffer for reprogramming data, functions as an inactive bank during switching operations, and provides storage for backup software versions. This multi-functionality allows the system to achieve double-bank capabilities without dedicating permanent memory space for these purposes, thus improving overall memory capacity utilization while maintaining software rewriting capability.
3Loss of time
If external storage is used as inactive bank, then activation time for bank switching is reduced, but device complexity increases
Solution Approach 1:
The patent segments the memory system into internal non-volatile memory and external storage, with clear division of responsibilities. The internal memory maintains software while the external storage handles reprogramming data and acts as inactive bank. This segmentation allows independent optimization of each component and simplifies the control logic for bank switching, as the system can directly switch between internal memory and external storage without complex coordination.
Data Source
AI summary
A vehicular electronic control device comprises: a microcontroller including a nonvolatile memory which can store software including programs and data, the nonvolatile memory including a first area and a second area as memory areas, and a control unit which includes a first core and a second core and which executes, on at least one of the first and second cores, a rewriting program for rewriting software; and an external storage which is provided externally to the microcontroller and which temporarily stores reprogramming data for updating software. If the control unit determines a rewrite of its own software on the basis of specifications data, the control unit uses a memory area in the external storage to rewrite the software stored in the nonvolatile memory.