Warren Gay Custom Raspberry Pi Interfaces Design and build hardware interfaces for the Raspberry Pi Warren Gay St Catharines, Ontario, Canada Any source code or other supplementary material referenced by the author in this book is available to readers on GitHub via the book’s product page, located at www.apress.com/978-1-4842-2405-2 . For more detailed information, please visit http://www.apress.com/source-code . ISBN 978-1-4842-2405-2 e-ISBN 978-1-4842-2406-9 DOI 10.1007/978-1-4842-2406-9 Library of Congress Control Number: 2017931068 © Warren Gay 2017 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. Trademarked names, logos, and images may appear in this book. Rather than use a trademark symbol with every occurrence of a trademarked name, logo, or image we use the names, logos, and images only in an editorial fashion and to the benefit of the trademark owner, with no intention of infringement of the trademark. The use in this publication of trade names, trademarks, service marks, and similar terms, even if they are not identified as such, is not to be taken as an expression of opinion as to whether or not they are subject to proprietary rights. While the advice and information in this book are believed to be true and accurate at the date of publication, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with respect to the material contained herein. the material contained herein. Printed on acid-free paper Distributed to the book trade worldwide by Springer Science+Business Media New York, 233 Spring Street, 6th Floor, New York, NY 10013. Phone 1-800- SPRINGER, fax (201) 348-4505, e-mail [email protected], or visit www.springeronline.com. Apress Media, LLC is a California LLC and the sole member (owner) is Springer Science + Business Media Finance Inc (SSBM Finance Inc). SSBM Finance Inc is a Delaware corporation. Contents Chapter 1: Introduction Raspberry Pi 3 and Zero Why GPIO Is Important What to Purchase Software to Download Let’s Begin Chapter 2: 3V/ 5V Signal Interfacing 7400 Series (TTL) 3. 3V Logic Voltage Dividers 7400 Series Derivative Families Unused CMOS Inputs Converting 5V to 3V Input: 74LVC245 Converting 5V to 3V Input: 74LVC244 CD4049/ CD4050 Input Protection Diodes Converting 3 Volts to 5 Volts with the HCT Family 74HCT245 74HCT244