Raspberry Pi 3 Bare Metal
FreeBare metal Raspberry Pi 3 tutorial – turning on the ACT LED with GPU mailboxes
FreeFree tier
About Raspberry Pi 3 Bare Metal
A step-by-step tutorial and code repository for bare metal programming on the Raspberry Pi 3, starting with turning on the ACT LED using assembly language and mailbox communication with the VideoCore GPU. Part 1 of a series that covers the boot process, required toolchain (arm-none-eabi), and SD card setup.
Key Features
Assembly language entry point (_start) and section setup
Mailbox communication between ARM CPU and VideoCore GPU
Controls ACT LED via virtual GPIO on Raspberry Pi 3
Explains entire boot chain: GPU bootloader → bootcode.bin → start.elf → kernel.img
Includes source code on GitHub for hands-on learning
Requires only arm-none-eabi toolchain and Raspberry Pi boot files
Pros & Cons
Pros
- Clear, well-documented boot process for Raspberry Pi 3
- Practical first project: turning on the ACT LED
- Open source and free to use
- Source code available on GitHub for reference
Cons
- Only covers the first step (LED blink) in Part 1
- Specific to Raspberry Pi 3; not directly applicable to Pi 2 or other platforms
- Requires external toolchain and knowledge of assembly
- No continued development or updates indicated after 2016
Best For
Learning bare metal embedded programming on Raspberry Pi 3Understanding GPU-ARM communication through mailboxesBuilding low-level hardware control for Raspberry Pi 3Educational resource for operating system development basics
FAQ
What is bare metal programming?
Bare metal programming is writing code that runs directly on the hardware without an operating system. This tutorial shows how to write assembly code for the Raspberry Pi 3 to control hardware like the ACT LED.
How do you control the ACT LED on Raspberry Pi 3?
The ACT LED on the Raspberry Pi 3 is controlled via the VideoCore GPU using a mailbox system. The ARM CPU sends a property tags message to the GPU to set the LED state.
What tools are needed to follow this tutorial?
You need the arm-none-eabi toolchain to assemble the code, and the Raspberry Pi boot files (bootcode.bin and start.elf) to boot the Pi. The tutorial also provides a kernel.img file.