📟 STM32 FreeRTOS CLI Playground

Advanced Embedded Firmware • NUCLEO-F446RE • FreeRTOS • UART • CLI • Logging System

This project is a fully-featured embedded firmware playground built on the STM32 NUCLEO-F446RE.
It demonstrates real-world, production-style firmware patterns, including:

• FreeRTOS multithreading
• Interrupt-driven UART RX
• Multi-word command line interface (CLI)
• Log message queue (decouples logging from user input)
• Thread-safe UART printing with mutex
• Virtual temperature sensor module
• Firmware versioning
• ANSI terminal control (clear screen)

This is designed as a professional portfolio project to demonstrate modern embedded-firmware architecture and RTOS design.

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🚀 Features

✔ FreeRTOS Tasks

Task	Purpose
LEDTask	Heartbeat LED (500ms)
SensorTask	Reads a virtual sensor every 1s, pushes logs to queue
CLITask	Owns UART, handles CLI, prints logs

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✔ Command Line Interface (Multi-Word)

Supports both long and short commands:

Command	Meaning
help	Show available commands
status	System health
version	Firmware version + build date/time
clear / cls	Clear terminal screen
led toggle / t	Toggle LED
sensor read / r	Read temperature sensor
log start / l	Start periodic logging
log stop / x	Stop periodic logging

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✔ Logging System (Non-Blocking)

A dedicated log queue ensures logging never interrupts typing.

Producers:

• TIM2 interrupt callback
• SensorTask

Consumer:

• CLITask (sole owner of UART TX)

This mirrors real RTOS firmware where logs flow from many contexts but only one task owns the UART/debug port.

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✔ Thread-Safe UART

All UART writes go through:

• uart_print()
• uart_write_char()

Protected with a FreeRTOS mutex when scheduler is active.

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✔ Versioning Built In

Version info displayed via version command:

Firmware v1.8.0
Built on Feb 2025 at HH:MM:SS

Version history embedded at top of main.c.

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✔ Virtual Sensor Module

Located in:

Core/Src/sensor.c
Core/Inc/sensor.h

Simulates temperature readings (float °C) and demonstrates how a real I2C/SPI driver integrates.

Upgrade path: BME280 real sensor via I2C (planned v1.9.0).

---

🧩 System Architecture

+-----------------------+
|       TIM2 ISR        |
|  (periodic logging)   |
+----------+------------+
           |
           v (non-blocking enqueue)
   +------------------------+
   |      logQueue          |
   |   (LogMessage_t)       |
   +------------+-----------+
                |
                v
+---------------+------------------+
|             CLITask              |
|     - consumes logQueue          |
|     - prints logs                |
|     - processes CLI commands     |
|     - owns UART TX               |
+---------------+------------------+
                |
                v
        +---------------+
        |   UART2 TX    |
        +---------------+

---

🧵 FreeRTOS Task Overview

                 +------------------+
                 |     LEDTask      |
                 |  toggle LED/500ms|
                 +------------------+

+------------+          +----------------+
|  TIM2 ISR  |  --->    |  logQueue      |
|  produces  |          +----------------+
+------------+                  |
                                |
+-----------------+      +-----------------+
|   SensorTask    | ---> |     CLITask     |
| produces logs   |      | processes logs  |
+-----------------+      | & CLI commands  |
                          +----------------+

---

🖥 CLI Example Session

System boot OK

CLI Ready
> help
Commands:
  help                - show this help
  status              - show system status
  version             - show firmware version
  clear / cls         - clear terminal screen
  led toggle          - toggle LED
  sensor read         - read sensor once
  log start           - enable timer-based logging
  log stop            - disable timer-based logging

> version
Firmware v1.8.0
Built on Feb 2025 at 20:41:13

> log start
Logging started

LOG: 23.1 C
LOG: 23.2 C
LOG: 23.3 C

> clear
> 

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📦 Project Structure

.
├── Core
│   ├── Inc
│   │   ├── main.h
│   │   └── sensor.h
│   └── Src
│       ├── main.c
│       └── sensor.c
├── Drivers
├── README.md
└── *.ioc (CubeMX configuration)

---

📚 Firmware Version History

Version	Changes
v1.0.0	Basic LED timer
v1.1.0	UART support
v1.2.0	Simple single-char CLI
v1.3.0	Virtual sensor module
v1.4.0	FreeRTOS tasks added
v1.5.0	UART mutex + thread-safe prints
v1.6.0	Multi-word CLI
v1.7.0	Log queue (decoupled logging)
v1.8.0	Added clear command
v1.8.1	Remove SensorTask logging

Next planned:

• v1.9.0 — Real I2C BME280 sensor
• v2.0.0 — UART DMA circular buffer + log levels

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🛠 Build & Flash

1. Open in STM32CubeIDE
2. Build (Ctrl + B)
3. Flash (Run → Debug)

UART Settings:

• 115200 baud
• 8-N-1
• No flow control

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🤝 Contributing / Feature Ideas

• Add BME280 I2C sensor
• Add ring buffer or UART DMA idle detection
• Add unit tests (Unity + Ceedling)
• Add configuration system + persistent settings
• Add CLI history + tab completion

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📄 License

MIT License.