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
About the Author
About the Reviewer

Why ensuring mutual exclusion is important when accessing shared resources

A fundamental problem in multitasking is accessing shared resources. Text books often introduce this topic by considering the following problem. Imagine two tasks, both having access to a global variable. The job of one task, called an incrementer, is to increment the shared variable. The other task, called the decrementer, decrements the shared variable. The increment and decrement operations in each task are embedded within identical for loops. In this way, we arrange for the variable to be incremented and decremented the same number of times. The shared variable is reset to zero before the tasks are created and run. Once the tasks complete, one may expect the value of the shared variable to equal zero, as increment and decrement have been executed in equal measure by the two tasks. This recipe, named RTOS_Sem_c8v0, illustrates that, surprisingly, this is not the case.

How to do it…

  1. Create a new project and using...