This is a major release with significant changes including migration to the new Arduino Core API, board naming convention updates, and the removal of legacy boards.

⚠️ Breaking Changes

Arduino Core API Migration

• Migrated to the new Arduino Core API: The entire core has been refactored to use the official ArduinoCore-API. This brings better compatibility across different Arduino cores and with modern Arduino libraries but may require code adjustments for existing projects.

Board and Vendor Naming Convention Changes

• Index file renamed from package_infineon_index.json to package_xmc_index.json, please update the URL in the Arduino preferences, instructions here.
• Vendor name changed from Infineon to infineon (lowercase) in package and platform files to be consistent with naming conventions across our Arduino cores and to avoid issues with Windows-based systems (case insensitivity).
• Board names have been standardized to follow the official kit naming convention:
  • XMC1100_Boot_Kit → KIT_XMC11_BOOT_001
  • XMC1100_XMC2GO → KIT_XMC_2GO_XMC1100_V1
  • XMC1300_Boot_Kit → KIT_XMC13_BOOT_001
  • XMC1400_Kit_for_Arduino → KIT_XMC1400_ARDUINO
  • XMC1400_XMC2GO → KIT_XMC14_2GO
  • XMC4700_Relax_Kit → KIT_XMC47_RELAX
• Old board variant macros are preserved for backwards compatibility via build.board_variant_old in boards.txt.

Wire/I2C Library Changes

• The Wire library has been completely refactored to inherit from HardwareI2C.
• Ring buffer implementation added for I2C communication.
• Error handling has been improved with proper return codes.

SPI Library Changes

• SPI library refactored with updated transfer function logic.
• Changes to SPI pin configurations across all variants.

🗑️ Removed Boards

The following boards have been removed from V4.0.0 and are only supported up to V3.x:

✨ Added Features

Core Functions

• setAnalogWriteFrequency() function: New function to configure PWM frequency dynamically.
• random() implementation: Added proper random number generation implementation.
• pulseIn() improvements: Updated pulse measurement implementation using millis().
• shiftIn()/shiftOut() implementation: Added shift register functions.
• sbrk() function declaration: Added for proper memory allocation support.

Debugging

• Cortex Debugger Integration: Added support for Cortex debugging with automatic launch.json generation.
• Generic gen_launch.sh script: Tool to configure build ELF and JSON paths for debugging.

Tone Function

• Reworked Tone implementation with proper CCU timer handling.
• Support for multiple tone pins (configurable via NUM_TONE_PINS).
• Frequency range: 1 Hz to 500 Hz (software-derived from Systick).

Testing Infrastructure

• Added comprehensive Hardware-in-the-Loop (HIL) test integration.
• Arduino Core Tests added as submodule for standardized testing.
• Unity test framework integration for all boards.

🗑️ Removed Features

• OneWire library removed from built-in libraries: Now available as external submodule.
• XMC1100 H-Bridge 2GO support removed from documentation.

🐛 Bugfixes

• I2C scan bug fixed: Corrected issue in Wire library affecting device scanning.
• Digital I/O fixes: Removed invalid pin condition checks, added flag for current pin status.
• Tone function noTone() fix: Corrected the noTone function implementation.
• Platform.txt typo fix: Fixed critical typo/bug in platform configuration.
• XMC1400 Arduino pinout fixes: Updated pin configurations for correct operation.
• Higher frequency PWM fix for XMC1400: Resolved issue with PWM at higher frequencies.
• Interrupt handler fixes: Corrected interrupt code for invalid pin/mode handling.
• Fixed incompatibility with arm_math.h: Modified analog macros to avoid naming conflict.

🔧 Improvements

Documentation

• Added installation reference documentation.
• Updated Arduino deviations documentation with Tone frequency details.
• Added known issues documentation for XMC1300 Boot Kit.
• Improved documentation for analog macros and built-in libraries.

Flasher Tool

• Updated xmc-flasher.py with improved firmware flag handling.
• Added custom flag to disable J-Link auto-update.
• Better logging and error messages.

DevOps & CI/CD

• Migrated to reusable GitHub workflows.
• Added compile checks for all library examples.
• Pre-commit hooks enabled for code quality.
• Added CODEOWNERS file for better code review management.

Pin Configurations

• Updated XMC1400 Arduino pinout diagram.
• Improved pin configurations for all supported boards.
• Added CCU8V3 macro support for XMC1400 variants.

📦 Supported Boards in V4.0.0

Contributors

• @jaenrig-ifx
• @LinjingZhang
• @dineshgit411
• @wxyyy0117
• @ederjc

Full Changelog: V3.5.2...4.0.0