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

Using timers to create a digital clock


A digital clock application provides a good platform to illustrate the components that we discussed in this chapter. We'll use PuTTY to allow the user to set the time and then call HAL_GetTick () to provide a time-base for our digital clock that is displayed on the GLCD. We'll call this recipe ticToc_c3v0.

How to do it…

Follow the following steps to create a digital clock:

  1. Create a new folder for the ticToc_c3v0 recipe and, within it, a new project (ticToc) and use the RTE manager to select board support for Graphic LCD.

  2. Copy the retarget.c, serial.c and serial.h files to the project folder and add them to the project.

  3. Define a new type (time_t) in the ticToc.h header file. Please note that we could declare each variable (hours, minutes, seconds, and so on) as separate unsigned integers, but it is better practice to group them together as a structured type named time_t:

    #ifndef __TICTOC_H
    #define __TICTOC_H
    
    typedef struct {      /* structure of the clock...