Book Image

ARM® Cortex® M4 Cookbook

By : Mark Fisher, Dr. Mark Fisher
Book Image

ARM® Cortex® M4 Cookbook

By: Mark Fisher, Dr. Mark Fisher

Overview of this book

Embedded microcontrollers are at the core of many everyday electronic devices. Electronic automotive systems rely on these devices for engine management, anti-lock brakes, in car entertainment, automatic transmission, active suspension, satellite navigation, etc. The so-called internet of things drives the market for such technology, so much so that embedded cores now represent 90% of all processor’s sold. The ARM Cortex-M4 is one of the most powerful microcontrollers on the market and includes a floating point unit (FPU) which enables it to address applications. The ARM Cortex-M4 Microcontroller Cookbook provides a practical introduction to programming an embedded microcontroller architecture. This book attempts to address this through a series of recipes that develop embedded applications targeting the ARM-Cortex M4 device family. The recipes in this book have all been tested using the Keil MCBSTM32F400 board. This board includes a small graphic LCD touchscreen (320x240 pixels) that can be used to create a variety of 2D gaming applications. These motivate a younger audience and are used throughout the book to illustrate particular hardware peripherals and software concepts. C language is used predominantly throughout but one chapter is devoted to recipes involving assembly language. Programs are mostly written using ARM’s free microcontroller development kit (MDK) but for those looking for open source development environments the book also shows how to configure the ARM-GNU toolchain. Some of the recipes described in the book are the basis for laboratories and assignments undertaken by undergraduates.
Table of Contents (16 chapters)
ARM Cortex M4 Cookbook
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
Index

Writing Cortex-M4 assembly language


Before we start to write an assembly language subroutine, we need an idea of what the function has to achieve. The best way to specify this is to first write the function in a high-level language, such as C, and then translate the C code into assembly language line by line. Some experienced assembly language programmers argue that this is inefficient, but the technique produces well-documented code that can be optimized in further iterations of the design.

Getting ready

To translate the C code, we need to be familiar with both the instruction set and the addressing modes that are used by the Cortex-M4. Details of the instruction set can be found in ARM's Architecture Reference Manual and also in the ARM Cortex-M4 Generic User Guide (http://infocenter.arm.com/). Addressing modes are fundamental to a general understanding of computer architecture, but they are of practical interest to compiler writers and those writing assembly language. The following paragraph...