Cover - 235.qxp 12/30/2009 11:32 AM Page 1 Various 32-Bit Possibilities, p. 30 • Floating Point for DSP on an FPGA, p. 46 • Forward Error Correction Explained, p. 62 www.circuitcellar.com CIRCUITTHEMAGAZINEFOR COMPUTER CELLAR APPLICATIONS #235 February 2010 WIRELESS COMMUNICATIONS Multi-Functional Wireless Monitoring and Control Build a WWVB-Style Signal Transmitter Customize an Embedded MCU Environment The Advanced Encryption Standard Explained Directional Light Sensor Design $5.95 U.S. ($6.95 Canada) C2.qxp 12/4/2009 2:11 PM Page 1 SSH Encrypted SERIAL TO ETHERNET SOLUTIONS Instantly network-enable any serial device Works out of the box - Device P/N: SB70LC-100CR no programming is required Kit P/N: NNDK-SB70LC-KIT Customize to suit any application $47 SB70LC with low-cost development kit 256-bit encryption protects data Qty. 1000 2-port serial-to-Ethernet server from unauthorized monitoring Features: 10/100 Ethernet TCP/UDP/SSH/SSL modes DHCP/Static IP Support Data rates up to 921.6kbps Web-based configuration Device P/N: SB700-EX-100CR Need a custom solution? 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Device P/N: CB34-EX-100IR Kit P/N: NNDK-CB34EX-KIT CB34EX Information and Sales | [email protected] $149 Web | www.netburner.com Qty. 1000 industrial temperature grade Telephone | 1-800-695-6828 2-port serial-to-Ethernet server with RS-232 & RS-485/422 support and terminal block connector 9.qxp 8/7/2008 11:04 AM Page 1 2-3.qxp 11/2/2009 3:52 PM Page 2 2-3.qxp 11/2/2009 3:52 PM Page 3 Task_Masthead_235.qxp 1/13/2010 11:58 AM Page 4 ASK ® TMANAGER CIRCUIT CELLAR THE MAGAZINE FOR COMPUTER APPLICATIONS FOUNDER/EDITORIAL DIRECTOR PUBLISHER Choose Your Own Design Adventure Steve Ciarcia Hugo Vanhaecke MANAGING EDITOR MARKETING C. J. Abate Shannon Barraclough When I was a child, I read a few of the books in Bantam’s WEST COAST EDITOR CUSTOMER SERVICE “Choose Your Own Adventure” series. The point was to Tom Cantrell Debbie Lavoie make decisions that would influence the course of the tale. CONTRIBUTING EDITORS CONTROLLER Decisions were presented in a simple format. Example: To Jeff Bachiochi Jeff Yanco do X, turn to page 5. To do Y, turn to page 10. As a book’s main Robert Lacoste ART DIRECTOR character, I’d drive the story by turning to certain pages and George Martin Ed Nisley KC Prescott then reading on. Some choices led to situations in which the GRAPHIC DESIGNERS main character was rewarded. Other choices led to negative NEW PRODUCTS EDITOR John Gorsky Grace Chen scenarios, such as the main character’s death. Thus, each book Carey Penney had a few possible endings. Hmm. That’s kind of like each PROJECT EDITORS Gary Bodley STAFF ENGINEER issue of Circuit Cellar (except for the death part). Ken Davidson John Gorsky Let’s say that while reading a project-centric article you David Tweed become so interested in a part that you immediately go to the manufacturer’s website. That’s one adventure. Now imagine that instead of checking out the part you decide to get more information by emailing the author. That’s another adventure. The great thing about Circuit Cellar is that each issue provides ADVERTISING 800.454.3741 • 978.281.7708 • www.circuitcellar.com/advertise the possibility for dozens of engineering adventures. You’re in charge. ADVERTISING REPRESENTATIVE I urge you to approach this issue in the spirit of choosing Peter Wostrel Strategic Media Marketing, Inc. your own adventure. Are you ready? Let’s begin. 1187 Washington St., Gloucester, MA 01930 USA Turn to page 16 to learn how to build an RFID-based moni- 800.454.3741 • 978.281.7708 toring and control system. Brian Millier describes how he [email protected] • www.smmarketing.us Fax: 978.281.7706 designed a wireless control system for a liquid nitrogen tank. ADVERTISING COORDINATOR To learn how to start an FPGA-based embedded design, jump Valerie Luster to John Clayton’s article on page 24. He covers topics ranging E-mail: [email protected] from custom development environments to HDL coding/syn- thesis tools. For more FPGA-related content, check out Bruce Cover photography by Chris Rakoczy—Rakoczy Photography www.rakoczyphoto.com Land’s article on page 46. PRINTED IN THE UNITED STATES Skip to page 30 to learn why Tom Cantrell says many MCU suppliers are “betting” on the ARM Cortex-M3. Are CONTACTS SUBSCRIPTIONS you with them? On page 38, Ed Nisley presents a “totally fea- Information: www.circuitcellar.com/subscribe, E-mail: [email protected] Subscribe: 800.269.6301, www.circuitcellar.com/subscribe, Circuit Cellar Subscriptions, P.O. Box 5650, tureless clock” design, which requires you to first build a Hanover, NH 03755-5650 WWVB simulator. Address Changes/Problems: E-mail: [email protected] GENERAL INFORMATION Are you fascinated in the Advanced Encryption Standard 860.875.2199, Fax: 860.871.0411, E-mail: [email protected] (AES) but put off in the complicated math? You aren’t alone. Editorial Office: Editor, Circuit Cellar, 4 Park St., Vernon, CT 06066, E-mail: [email protected] New Products: New Products, Circuit Cellar, 4 Park St., Vernon, CT 06066, E-mail: [email protected] Go to page 54 for Monte Dalrymple’s useful presentation of the AUTHORIZED REPRINTS INFORMATION 860.875.2199, E-mail: [email protected] AES. If you’re confused by the topic of forward error correction AUTHORS (FEC), refer to Robert Lacoste’s article on the subject (p. 62). It’s Authors’ e-mail addresses (when available) are included at the end of each article. a great introduction to the subject. Jeff Bachiochi wraps up the articles section of the issue with CIRCUIT CELLAR®, THE MAGAZINE FOR COMPUTER APPLICATIONS (ISSN 1528-0608) is published monthly by Circuit Cellar Incorporated, 4 Park Street, Vernon, CT 06066. Periodical rates paid at Vernon, CT and additional offices. One-year (12 issues) the first installment of his “Sun Tracker” article series (p. 68). subscription rate USA and possessions $29.95, Canada/Mexico $34.95, all other countries $49.95.Two-year (24 issues) sub- scription rate USA and possessions $49.95, Canada/Mexico $59.95, all other countries $85. All subscription orders payable in This project enables you to tell time with a mixture of old and U.S. funds only via Visa, MasterCard, international postal money order, or check drawn on U.S. bank. Direct subscription orders new technologies. Sundials, sensors, and MCUs. Now that’s a and subscription-related questions to Circuit Cellar Subscriptions, P.O. Box 5650, Hanover, NH 03755-5650 or call 800.269.6301. bill of materials bound to lead to an amazing design adventure. Postmaster: Send address changes to Circuit Cellar, Circulation Dept., P.O. Box 5650, Hanover, NH 03755-5650. As usual, we have a lot of handy information packed in a Circuit Cellar® makes no warranties and assumes no responsibility or liability of any kind for errors in these programs or schematics or for the single issue. You can’t build all the projects and test all the the- consequences of any such errors. Furthermore, because of possible variation in the quality and condition of materials and workmanship of read- er-assembled projects, Circuit Cellar® disclaims any responsibility for the safe and proper function of reader-assembled projects based upon or ories at once, so choose your adventure wisely. There’s no from plans, descriptions, or information published by Circuit Cellar®. The information provided by Circuit Cellar® is for educational purposes. Circuit Cellar® makes no claims or warrants that readers have a right to build things based upon these ideas under patent or other relevant intellectual property law in their jurisdiction, or that readers have a right to rush. You can always return to the issue to start a new journey. construct or operate any of the devices described herein under the relevant patent or other intellectual property law of the reader’s jurisdiction. The reader assumes any risk of infringement liability for constructing or operating such devices. Entire contents copyright © 2010 by Circuit Cellar, Incorporated. All rights reserved. Circuit Cellar is a registered trademark of Circuit Cellar, Inc. [email protected] Reproduction of this publication in whole or in part without written consent from Circuit Cellar Inc. is prohibited. February 2010 – February Issue 2010 235 4 CIRCUIT CELLAR® • www.circuitcellar.com 5.qxp 1/11/2010 9:11 AM Page 1 INSIDE ISSUE BONUS CONTENT Using USB for Computer Interfacing Projects 2February 20103• Wireless Communications5 16 RFID-Based Liquid Control (Part 1) Working with Off-the-Shelf Components Brian Millier 24 FPGA Embedded Microcontroller Environment John Clayton 46 Floating Point for DSP p. 16, RFID Tech Bruce Land p. 24, Designing 54 Advanced Encryption Standard with an FPGA Understanding AES Without Math Monte Dalrymple p. 38, Featureless Clock Design 30 SILICON UPDATE A Winning Hand Betting on the ARM Cortex-M3 Tom Cantrell TASK MANAGER 4 Choose Your Own Design Adventure 38 ABOVE THE GROUND PLANE Totally Featureless Clock (Part 1) C. J. Abate WWVB Simulator Ed Nisley NEW PRODUCT NEWS 8 edited by John Gorsky 62 THE DARKER SIDE Living with Errors CROSSWORD 74 An Introduction to Forward Error Correction Robert Lacoste INDEX OF ADVERTISERS 79 236 Preview 68 FROM THE BENCH Sun Tracker (Part 1) PRIORITY INTERRUPT 80 Create a Directional Light Sensor Feature Creep February 2010 – Issue 235 February 2010 Jeff Bachiochi Steve Ciarcia 6 CIRCUIT CELLAR® • www.circuitcellar.com 29.qxp 11/30/2009 12:49 PM Page 1 The New High-Performance Catalog Industry’s only full-featured online catalog •Browse •Search •Check Stocktock •B•Buyuy Try It Now at www.mouser.com WARNING: Designing with Hot, New Products May Cause A Time-to-Market Advantage.