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Bare-metal C programming on ARM

This repository contains a tutorial ebook concerning programming a bare-metal ARM system. More specifically it deals with a ARMv7A version of the ARM Versatile Express platform, emulated on a regular PC through QEMU. You can explore the repository, or read things in order.

Table of Contents

An up-to-date PDF version is also available.

The following chapters can be thought of as the first edition of the ebook, providing a complete path from getting started to a working program that uses hardware features.

  • Chapter 0: Introduction. A brief intro to the subject and the ebook.
  • Chapter 1: Setup. A short chapter dealing with preparing a Linux environment for further development.
  • Chapter 2: The first boot. Basic use of QEMU and the cross-compiler toolchain, getting the simplest possible code to run.
  • Chapter 3: Adding a bootloader. Building the highly popular U-Boot bootloader, and getting it to boot our own code.
  • Chapter 4: Preparing a C environment. This chapter deals with the necessary work for getting from startup in assembly code to C code.
  • Chapter 5: Build & debug system. Here we show how the work can be streamlined by adding a CMake-based build system, and how the bare-metal program can be debugged.
  • Chapter 6: UART driver development. In this chapter, a device driver for a UART gets written.
  • Chapter 7: Interrupts. The chapter goes through setting up the ARM Generic Interrupt Controller, using it to receive and respond to interrupts. Also the UART driver gets adapted to use interrupts.
  • Chapter 8 - WIP: Scheduling. Work in progress.

Repository structure

The repository consists of two top-level folders. The doc folder contains the actual tutorial chapters. The src folder contains the source code corresponding to each chapter. So, for instance, src/04_cenv contains the source code as it looks after completing Chapter 4.

Additionally, the src folder has some shared things. src/common_uboot holds a stripped-down version of U-Boot used in the examples.

Have fun, and feel free to tweak and experiment, that being a great way to learn!