October 2024

Overview

October marked the beginning of a significant firmware modernization effort, transitioning the core widget controller from a bare-metal implementation to a structured RTOS-based architecture. This foundational work enables future feature development while improving system stability and power efficiency.

Key Changes & Features

• RTOS Migration
  • Migrated the main event loop to FreeRTOS, enabling preemptive multitasking and improving responsiveness during high-load scenarios.
  • Implemented task priorities for sensor polling, communication handling, and user interface updates.
  • Added mutex protection for shared hardware resources (SPI bus, I2C peripherals).
• Power Management Foundation
  • Designed a three-tier power management system: Active, Idle, and Deep Sleep modes.
  • Implemented automatic sleep transitions based on inactivity timeouts.
  • Added wake-on-interrupt support for external sensor triggers.
• Communication Stack Improvements
  • Refactored the serial protocol handler to support asynchronous message processing.
  • Added CRC-16 checksums to all command packets for improved reliability.
  • Implemented a retry mechanism with exponential backoff for failed transmissions.

Technologies & Languages

• Embedded C: Primary language for firmware development targeting the STM32F4 series.
• Python: Used for the command-line configuration tool and automated test scripts.
• FreeRTOS: Real-time operating system providing task scheduling and synchronization primitives.

Patterns & Architecture

• Task-Based Design: Moved from a monolithic super-loop to dedicated tasks for each subsystem, improving code maintainability.
• Message Queue Communication: Implemented inter-task communication using FreeRTOS queues, decoupling producers from consumers.
• Hardware Abstraction Layer: Created a HAL layer to isolate hardware-specific code, enabling easier porting to new microcontrollers.