Books and boards, Part 2.
Two kits from Texas Instruments, Dolphin-LP-EVM, $399 (low power, +7 dBm) and Dolphin HP-EVM, $499 (high power, +23 dBm), show how the Dolphin frequency-hopping spread-spectrum chipset simplifies communication in the crowded industrial scientific and medical (ISM) spectrum. The demo kit includes two RF modules and two base modules that connect to host PCs through serial ports. The battery-powered modules can communicate over a single channel or via frequency hopping. (You'll need two AA batteries to power each base module. The kit includes serial-port cables.)
Software on an accompanying CD-ROM installed quickly and let me send random-length packets of random data between the transceivers, which I placed about 15 feet apart. (TI's data provides range-test results that show a 0.2-mile range for a low-power transceiver and a 1-mile range for a high-power unit on a line-of-sight range.) During one test, approximately 14,000 packets achieved a 99.9 percent success rate, which included "retries," and an 82 percent success rate without retries. During that test, I did my best to block the signal. An unobstructed line-of-sight test returned better results; 100 percent success with retries and 97.3 percent without them.
TI's Dolphin chip set includes an RF-transceiver chip (TRF6903) and a baseband ASIC (DBB03A) chip. The latter device controls transceiver operations and provides the interface to a host device. If designers wish, they can substitute a microcontroller, such as a TI MSP430, for the ASIC. In fact, the DBB03A ASIC appears much like a microcontroller, complete with I/O. JTAG, and debug ports. Don't expect to program the ASIC, though: The control code resides in ROM.
The kit successfully demonstrated reliable serial RF communication of serial data. Engineers interested in basic communication capabilities between devices or in a network of devices should give the demo kit and the Dolphin chipset a close look. The User's Guide manual provides reference-design information, but the manual could use a revision. I recommend you review the entire manual before you connect the modules. Although instructions describe how to mate a base module with an RF module, for example, you must go through 24 more pages to see the physical arrangements. (Yes, you can incorrectly mate the modules.) After reading the hardware-setup instructions, you'll go 30 pages to get to the software setup instructions. I expected more of a step-by-step start-up approach. In spite of the manual's organization, the kit and software proved easy to use and performed as expected.
Bring Discipline to Software Development
Ship It! by Jared Richardson and William Gwaltney, Jr., The Pragmatic Bookshelf, Raleigh, NC. 200 pgs. $29.95.
Finally a book about managing software projects you can actually use. The authors have combined a conversational tone with a wealth of information that includes "how-to-get-started," "self checks," and "warning signs" in each of the four main chapters. Whether you work with one partner or within a large development team, you'll like this book.
The authors start with basic information about managing resources, using a source-code-management tool, and developing consistent build scripts. Then they continue with development of test suites and techniques used to track code problems and bugs. You may find yourself saying, "Well, that seems obvious," but then ask yourself if you actually use the described techniques. Hmmm.
The chapter on pragmatic project techniques provides much information on managing software teams, from developing lists of tasks that your group can access and update to working together as a team. Don't expect deep lessons in management, though. The authors clearly focus on software-development projects. I enjoyed the chapter that covers "tracer bullet development," a technique that helps you define system objectives and start to develop code for them. The author's top-down technique makes much sense, and they suggest approaches that can help you better focus on an overall coding technique. This book will help even seasoned programmers take another look at their development processes.
A final chapter covers common problems and how to fix them. These problems range from tackling legacy code to working with unhappy managers. Eight appendices provide sources for more information, software tools, books, and web sites. All in all, Richardson and Gwaltney provide a valuable working manual for anyone involved with software.
8051 Book Misses the Mark
Embedded Programming with Field Programmable Mixed-Signal [mu]Controllers, by Moi Tin Chew and Gourab Sen Gupta. Available from Silicon Laboratories. 2005, 253 pages. $14.95. (www.silabs.com/mcu/textbook)
The 8051 microcontroller shows no sign of running out of applications to tackle. In this book, Chew and Gupta specifically examine the Silicon Laboratories' C8051F020 microcontroller; from the chip's architecture to its instruction set. Most op-code explanations include an example of what each instruction does. Few developers hand-code programs, so readers also get a brief introduction to C programming and to assembler operations and directives.
Chew and Gupta also explore the 8051's I/O ports and its crossbar switch. This internal switch matrix lets developers route I/O ports to specific pins on a C8051 chip, which can be handy as application requirements and capabilities change. Later, the authors pull together programming and I/O-port information as they develop and exercise an expansion board for Silicon Labs' C8051F020TB prototyping board ($75).
Unfortunately, the authors don't explain the setup of the prototyping and expansion boards, and they mention an evaluation board, possibly the C8051F020DK development kit ($129), only in passing. In this section, I expected the book to offer easy-to-follow instructions, or lab experiments, that pull together the I/O ports, programming techniques, and C or assembly-language operations. You will find some of that information in the 24 pages devoted to their expansion board, but I had a difficult time following it. The expansion board may prove helpful if you want to see how I/O ports and software control external devices, but the book lacks information about where to obtain the circuitry or the board.
The remainder of the book covers internal counters/timers, interrupts, analog converters, and serial I/O. You will find short program examples in these sections, but no flowcharts that help you visualize what takes place in software and in the hardware.
The authors deserve credit for adding to the available information about Silicon Labs 8051 microcontrollers, but the book falls short as a step-by-step manual that explains how to combines real hardware and software. If you need to investigate the Silicon Labs 8051 architecture, the book has value. If you want more general information about the 8051 chip, look elsewhere.
by Jon Titus, Senior Technical Editor
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|Title Annotation:||Embedded Systems|
|Publication:||ECN-Electronic Component News|
|Date:||Dec 15, 2005|
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