ARM Cortex-M Fault Analyzer

A GUI tool for analyzing fault exceptions on ARM Cortex-M microcontrollers.

Requirements

• Python 3.8+
• Standard library only (tkinter, json, os, sys, re, subprocess, datetime) - no third-party dependencies

Usage

python arm_fault_analyzer.py

Features

• Manual register input or loading from a JSON dump file
• MAP file support for two formats: AC6 armlink and GNU LD (auto-detected)
• PC / LR address resolution to function names via MAP file
• Register decoding: CFSR (MMFSR / BFSR / UFSR), HFSR, DFSR, AFSR, PSR
• ISR number decoding in PSR and EXC_RETURN decoding in LR
• Analysis of R0-R3, R12, SP: memory region, magic value detection, BFAR/MMFAR match
• Persistent analysis history across sessions
• Report export to a text file
• One-click copy of diagnostics to clipboard
• Localisation: interface language selectable in Settings (Russian / English); applied after restart

JSON Dump Format

{
    "R0":    "0x20000100",
    "R1":    "0x00000000",
    "R2":    "0x08001234",
    "R3":    "0xDEADBEEF",
    "R12":   "0x00000000",
    "SP":    "0x20004FF0",
    "LR":    "0x08000401",
    "PC":    "0x08002468",
    "PSR":   "0x01000000",
    "CFSR":  "0x00000082",
    "HFSR":  "0x40000000",
    "DFSR":  "0x00000000",
    "AFSR":  "0x00000000",
    "BFAR":  "0x20000100",
    "MMFAR": "0x00000000"
}

Not all fields are required - missing registers default to 0x00000000.

Data Files

File	Contents
arm_analyzer_config.json	Application settings, paths, recent file lists, language
arm_analyzer_history.json	Analysis history (up to N entries, configurable)
Locales/ru.json	UI strings and diagnostics - Russian
Locales/en.json	UI strings and diagnostics - English
Locales/help_ru.txt	Help tab content - Russian
Locales/help_en.txt	Help tab content - English

Settings

The Settings tab allows you to configure:

• Default directory for loading JSON dumps
• Default directory for saving reports
• Recent files list size (MAP and JSON), 1 to 20 entries
• Maximum history entries, 10 to 500
• Interface language (Russian / English) - applied on restart

To add a new language, create Locales/<lang>.json and Locales/help_<lang>.txt, then add the language code to the Combobox values in create_settings_tab().

Full usage guide, register descriptions, and common fault scenarios are available in the Help tab inside the application.

Interface

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Changelog

[1.3] - April 2026

Fixed

• Clearing history now immediately overwrites the history file (previously the file kept old data and history was restored on next launch)
• Resetting settings now saves the defaults to the config file immediately
• Information block in Settings now updates live when saving or resetting (previously required a restart to reflect changes)

Changed

• Config and history files moved to %APPDATA%\ARMFaultAnalyzer\ (Windows) / ~/.config/ARMFaultAnalyzer/ (Linux/macOS) - no longer placed next to the script
• History file directory is now configurable in Settings tab; defaults to the same folder as the config file
• Empty load/save path in the Information block now shows the script directory instead of "not set"
• Version button v1.x.x added to the bottom-left corner of the main window (opens About dialog)

Optimized

• History file now stores only register values per entry; decoded fields and diagnosis text (which were never displayed) have been removed - significantly reduces file size

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[1.2] - April 2026

Changed

• Localisation support (ru/en): JSON locale files + help text files, language selector in Settings, auto-restart on language change

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[1.1] - April 2026

Changed

• Added history saving for JSON and MAP files

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[1.0] - April 2026

• Initial release

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Document version: 1.3