A bare-metal programming demonstration for the Arduino Uno (ATmega328P) to blink the onboard LED using direct register-level C programming. This project uses only AVR-GCC and AVRDude, with no Arduino libraries.

• Toggles the onboard LED (pin 13 / PB5) every 500ms.
• Utilizes direct AVR register manipulation for maximum efficiency.
• Simple build and flash process using a Makefile.
• Compatible with a VS Code + PlatformIO workflow.
• Version-controlled with Git & GitHub.

• Microcontroller: ATmega328P (on an Arduino Uno board)
• Onboard LED: Connected to Pin 13 (Port B, Pin 5)
• Connection: Standard USB cable

• Linux ( Ubuntu).
• Visual Studio Code (or any text editor)
• AVR Toolchain: gcc-avr, avr-libc, avrdude
• make utility
• Git for version control

To install the required tools on a Debian/Ubuntu system:

sudo apt update
sudo apt install gcc-avr avr-libc avrdude

arduino_baremetal/
├── blink.c          # Main C source code for the blinking logic
├── Makefile         # Build and flash automation script
├── .gitignore       # Optional: Specifies files for Git to ignore
└── README.md        # This documentation file

git clone https://github.com/Sreyz03/arduino_baremetal.git
cd arduino_baremetal

Compile the source code to generate the executable .hex file.

make all

This command compiles blink.c → blink.o → blink.elf → blink.hex.

First, connect your Arduino and identify its serial port:

ls /dev/ttyACM*

Update the PORT variable in the Makefile if it's different from /dev/ttyACM0.

Then, upload the compiled code to the Arduino:

make flash

The onboard LED should now be blinking!

To remove all generated files (.o, .elf, .hex):

make clean

This project is licensed under the MIT License.