Microcomputer Endian Mode Switching via Flash Memory

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Solution Overview

Problem

Microcomputers require external terminals for endian selection, limiting the availability of pins for other uses and preventing users from dynamically changing between big-endian and little-endian modes internally.

Innovation Solution

Incorporating a data transfer circuit that reads and supplies endian information from flash memory areas specific to user boot and user modes to the CPU before reset release, eliminating the need for external terminals and allowing seamless mode switching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If external terminals are used for endian selection, then endian mode can be selected, but the number of available pins is reduced

Engineering Contradiction:

Improveendian mode selection capabilityVSAvoidnumber of available pins

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent extracts the endian selection function from external terminals and relocates it to internal memory storage. The endian information is stored in flash memory areas (user boot area or user area) and automatically read by the data transfer circuit, eliminating the need for external terminal pins while preserving the endian selection capability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The system performs self-configuration by automatically reading endian information from flash memory during startup. The data transfer circuit autonomously retrieves the endian setting based on operation mode and supplies it to the CPU without requiring external terminal input, enabling the system to configure itself.

Inventive Principle:

Principle #25Self-service

2Adaptability or versatility

If external terminals are used for endian selection, then endian mode can be changed, but users cannot dynamically switch modes during operation

Engineering Contradiction:

Improveendian mode switching capabilityVSAvoiddynamic mode switching during operation

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent implements dynamic endian mode switching by storing different endian information in different flash memory areas corresponding to different operation modes. The data transfer circuit dynamically selects which endian information to read based on the current operation mode, allowing the system to adaptively change endian settings during operation without external terminal intervention.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The endian information is pre-stored in flash memory areas before operation. The data transfer circuit reads the appropriate endian information in advance based on the operation mode and supplies it to the CPU before reset release, enabling seamless mode switching without requiring external terminal configuration at the time of mode change.

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If endian information is stored in external terminals, then endian selection is possible, but the information is vulnerable to deletion or restriction

Engineering Contradiction:

Improveendian information storageVSAvoidprotection against accidental deletion

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent embeds the endian information storage within the flash memory structure, nesting it within specific address spaces (user boot area or user area). This nested storage approach integrates the endian information protection into the existing memory architecture, making it resistant to external deletion or restriction while maintaining accessibility for legitimate operations.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The endian information is pre-stored in protected flash memory areas during manufacturing or initial setup. This preliminary action ensures the information is securely stored before any operation occurs, and the data transfer circuit is configured to read from these protected areas, preventing accidental deletion or unauthorized modification during normal operation.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS10140207B2Microcomputer having processor capable of changing endian based on endian information in memory

Publication Date: 2018.11.27 RENESAS ELECTRONICS CORP

AI summary

There is a need to provide a microcomputer capable of eliminating an external terminal for endian selection. Flash memory includes a user boot area for storing a program executed in user boot mode and corresponding endian information and a user area for storing a program executed in user mode and corresponding endian information. A data transfer circuit reads endian information stored in the user boot area or the user area in accordance with operation mode and supplies the endian information to a CPU before reset release of the CPU. Accordingly, an external terminal for endian selection can be eliminated.