i.MX6QDL Sabre-SD Boot LED

A dual-implementation educational project that simulates the boot LED sequence of the i.MX6QDL Sabre-SD development board through both console-based (C) and graphical (Python/Tkinter) interfaces.

Overview

This project provides a visual simulation of the 16-stage boot process used in the i.MX6QDL Sabre-SD development board. It demonstrates how embedded systems use LED indicators to show boot progression, making it an excellent educational tool for:

• Embedded systems students
• Linux boot process learners
• Embedded Linux developers
• Hardware simulation enthusiasts

Features

C Program (imx6qdl_sabre_led)

• Console-based ASCII art LED display
• Configurable boot speed
• Verbose mode for detailed stage information
• Lightweight, no dependencies
• Cross-platform compatible

Python GUI (led_gui.py)

• Interactive 4x4 LED grid visualization
• Real-time status display with descriptions
• Speed control slider (1x to 10x)
• Pause/Resume functionality
• Manual step-by-step progression
• Stage highlighting with color coding

🔢 Boot LED Sequence

The simulation follows a realistic 16-stage boot sequence:

Stage	LEDs	Description	Status
1. Power ON	LED0	Initial power-up and hardware initialization	🔴→🟢
2. U-Boot Stage	LED1–LED4	Bootloader initialization (4 phases)	🔴→🟢
3. Kernel Boot	LED5–LED8	Linux kernel loading and initialization	🔴→🟢
4. RootFS Mount	LED9–LED11	Root filesystem mounting (3 phases)	🔴→🟢
5. Services Init	LED12–LED14	Service initialization (Wi-Fi/Bluetooth/Ethernet)	🔴→🟢
6. System Ready	LED15	System fully booted and ready	🔴→🟢

Project Structure

imx6qdl-sabresd/
├── README.md                    # This file
├── imx6qdl_sabre_led.c         # C console implementation
├── led_gui.py                  # Python GUI implementation
├── Makefile                    # Compilation script for C program
├── imx6qdl_sabre_led          # Compiled binary (after make)
└── (generated files after compilation)

Quick Start

Prerequisites

For Python GUI:

sudo apt update
sudo apt install python3 python3-tk

For C Program:

sudo apt update
sudo apt install gcc make

Run Python GUI (Recommended for first-time users)

python3 led_gui.py

Compile and Run C Program

make
./imx6qdl_sabre_led

Usage

Python GUI Application

Launch the GUI with:

python3 led_gui.py

GUI Controls:

• Start/Stop Button: Begin or halt the simulation
• Speed Slider: Adjust boot speed (1-10)
• Step Button: Manually progress through stages
• Reset Button: Return to initial state
• LED Grid: Visual 4x4 display showing active LEDs

Visual Indicators:

• 🔴 Red: Stage not yet reached
• 🟢 Green: Active/current stage
• 🟡 Yellow: Completed stage
• 🔵 Blue: Service initialization stages

C Console Program

Basic Usage:

./imx6qdl_sabre_led

Command Line Options:

./imx6qdl_sabre_led [OPTIONS]

Options:
  -h, --help      Show this help message
  -s, --speed=N   Set delay between stages (1=fast, 10=slow, default=3)
  -v, --verbose   Show detailed status messages
  -q, --quiet     Minimal output (only LEDs)

Examples:

# Fast boot with details
./imx6qdl_sabre_led --speed=1 --verbose

# Slow, minimal display
./imx6qdl_sabre_led --speed=8 --quiet

# Default settings
./imx6qdl_sabre_led

Build Instructions

Compile C Program

# Clean build
make clean

# Compile
make

# Optional: Install to system (requires sudo)
sudo make install

Manual Compilation

gcc -o imx6qdl_sabre_led imx6qdl_sabre_led.c -Wall -Wextra -std=c99

Makefile Targets

make           # Compile program
make clean     # Remove compiled files
make install   # Install to /usr/local/bin
make uninstall # Remove from system
make debug     # Compile with debug symbols

LED Mapping Visualization

The 16 LEDs are logically arranged in a 4x4 grid:

┌─────┬─────┬─────┬─────┐
│ LED0│ LED1│ LED2│ LED3│  ← Row 1: Power & U-Boot
├─────┼─────┼─────┼─────┤
│ LED4│ LED5│ LED6│ LED7│  ← Row 2: U-Boot & Kernel
├─────┼─────┼─────┼─────┤
│ LED8│ LED9│ LED10│LED11│ ← Row 3: Kernel & RootFS
├─────┼─────┼─────┼─────┤
│ LED12│LED13│LED14│LED15│ ← Row 4: Services & Ready
└─────┴─────┴─────┴─────┘

Detailed Workflow

Simulation Flow

1. Initialization: All LEDs off (red)
2. Stage Progression: Each stage activates its LED(s)
3. Status Updates: Console/GUI updates with stage info
4. Completion: All LEDs active, system ready message

C Program Flow

main() → parse_args() → initialize() → simulate_boot() → cleanup()
           ↓                ↓              ↓                ↓
       Read options    Setup display   Loop through    Free resources
                                        16 stages
                                          ↓
                                    update_led() + delay()

Python GUI Flow

LEDSimulator() → __init__() → create_widgets() → start_simulation()
     ↓                ↓              ↓                  ↓
 Application      Initialize    Build GUI        Run boot sequence
                                            ↓
                                  update_leds() + schedule_next()

Testing

Quick Test Suite:

# Test C program
./imx6qdl_sabre_led --speed=2 --verbose
./imx6qdl_sabre_led --speed=5 --quiet

# Test Python GUI
python3 led_gui.py

# Test both implementations
chmod +x test.sh  # If test script exists
./test.sh

Expected Output Examples:

C Program:

[  ] LED0  [  ] LED1  [  ] LED2  [  ] LED3
[  ] LED4  [  ] LED5  [  ] LED6  [  ] LED7
[  ] LED8  [  ] LED9  [  ] LED10 [  ] LED11
[  ] LED12 [  ] LED13 [  ] LED14 [  ] LED15

Starting boot sequence...
Stage 0: Power ON - LED0
[ON] LED0  [  ] LED1  [  ] LED2  [  ] LED3
...

Python GUI:

• Interactive window with 4x4 LED grid
• Status bar showing current stage
• Control panel with buttons and slider

Customization

Modify Boot Parameters

In C program:

// Edit imx6qdl_sabre_led.c
#define DEFAULT_SPEED 3        // Change default speed
#define TOTAL_STAGES 16        // Number of LEDs
const char* stage_names[] = {  // Edit stage descriptions
    "Power ON",
    "U-Boot Phase 1",
    // ... etc
};

In Python GUI:

# Edit led_gui.py
STAGE_DESCRIPTIONS = {
    0: "Power ON - Hardware Initialization",
    1: "U-Boot Phase 1 - CPU Init",
    # ... etc
}
COLORS = {
    'off': '#ff4444',     # Change LED colors
    'on': '#44ff44',
    'active': '#ffff44'
}

Add New Features

1. Add sound effects: Integrate with pygame or system beep
2. Logging: Add file logging for boot sequence
3. Network simulation: Simulate network service initialization
4. Web interface: Create Flask/Django web version

Contributing

Contributions are welcome! Here's how you can help:

1. Fork the repository
2. Create a feature branch: git checkout -b feature/amazing-feature
3. Commit changes: git commit -m 'Add amazing feature'
4. Push to branch: git push origin feature/amazing-feature
5. Open a Pull Request

Development Guidelines

• Follow existing code style
• Add comments for complex logic
• Update documentation
• Test changes on both implementations
• Keep commits focused and atomic

Suggested Improvements

• Add error simulation mode
• Create web-based version
• Add real hardware integration
• Create Docker container
• Add unit tests
• Internationalization support

Educational Value

This project demonstrates:

• Embedded boot sequences: How hardware indicates boot progress
• Multi-language implementation: Same logic in C and Python
• Event-driven programming: GUI event handling
• System simulation: Modeling real hardware behavior
• Cross-platform development: Works on Linux, macOS, Windows

Troubleshooting

Issue	Solution
python3-tk not found	sudo apt install python3-tk (Debian/Ubuntu)
make: command not found	sudo apt install make
gcc: command not found	sudo apt install gcc
GUI window doesn't open	Check DISPLAY variable, try export DISPLAY=:0
Program runs too fast/slow	Use -s option to adjust speed

Acknowledgments

• Freescale/NXP for i.MX6QDL Sabre-SD board documentation
• Python Software Foundation for Tkinter
• GCC team for the C compiler
• Embedded Linux community for boot sequence references

Support & Contact

• Questions: Open a discussion in GitHub

Star History

If you find this project useful, please consider giving it a star! ⭐

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