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 a driver for the audio codec


The audio codec is a peripheral that enables an analog signal to be converted and coded to a digital data stream or conversely the data stream to be decoded and converted back to an analog signal (https://en.wikipedia.org/wiki/Codec). The MCBSTM32F400 evaluation board uses a CS42L52 device that is manufactured by Cirrus Logic (http://www.cirrus.com/en/products/). As, this codec is not yet included in Board Support, and as no CMSIS-compliant device driver is available, we are faced with the task of having to write our own driver.

However, this is not as daunting as it first appears because the code to set up and manage data transfer across the I2C bus can be lifted from the previous recipe (the Touch_STMPE811.c file) and the configuration of the CS42L52 codec is described in the data sheet. The recipe to develop and test this codec driver is called codecDemo_c6v0.

How to do it…

Perform the following steps to write a driver for the audio codec:

  1. Create a new...