Inexpensive development kits can realistically open the door to a world of options. In the past, designers would stick with a chip family or vendor due to the high cost of changing platforms and the difficulty in evaluating new systems outside their normal realm. Vendor loyalty is still valuable, but the ability to quickly evaluate new hardware platforms lets designers check out alternatives for their favored vendors or other vendors.
Cost isn't the only reason for the flood of new evaluation or development kits (although their inclusion of low-cost hardware and software tools certainly helps). For instance, there's the availability of powerful microcontrollers that can be programmed with familiar high-level languages like C and C++. Also, flash memory permits simple programming and standalone operation of user-programmed applications.
Open-source software (OSS) has made a serious dent in software tool cost. Many kits come with OSS packaged for that platform. Vendors like Green Hills Software, IAR, and Keil typically bundle their proprietary tools, often with some limitations, to compete or complement the collection of software included with a kit.
Support hardware prices and footprints have dropped significantly, too. Macraigor includes its JTAG technology on some evaluation boards so that developers need not contend with separate JTAG modules. Of course, the tradeoff is that the latter can be used with another board.
Not to be overlooked is the Universal Serial Bus (USB). Kits that use USB as an interface bring a number of features to the fore. It can provide power, eliminating the otherwise ubiquitous and costly power brick. It also brings a flexible interface often used with advanced debugging tools like JTAG. Moreover, it's the interface of choice, given today's laptop and desktop migration to USB-only interfaces.
As a result, many of today's kits come with extremely low pricetags. Even more expensive solutions offer significantly more functionality than in the past. So in a nutshell, designers can now reach various plateaus with such a broad range of solutions.
DEVELOPMENT PLATEAUS Not all kits are created equal. Therefore, it's handy to have a way to gauge kits (see "Reaching A Plateau," below). I've used a four-level system for grading kits in my EiED Online column. These range from initial kit-functionality demonstrations to full-blown development work. Kits can be divided into three general categories: demonstration, evaluation, and development.
Demonstration kits like those from Texas Instruments (Fig. 1) and Atmel (Fig. 2) are interesting because they're designed to reach Plateau 1, but they actually are good fits on the next two levels. But reaching these levels requires further work from the user—downloading the tools from the Internet and adding some hardware to the mix. Then again, what would you expect from something that costs $20?
Evaluation kits, the next step up, typically include a board, software, and documentation. They also may have additional diagnostic hardware. They're designed to cost as little as possible while providing tools suitable for application development. The software tools often are limited, though. For example, they may only work with the board provided, with the microcontrolleron the board, or with a matching diagnostic-tool. Code size and time limits are common-as well. Stay away from the latter if possible,-because the kit becomes useless if the software is no longer usable.
Development kits are usually designed to provide a platform that's as unrestricted as possible. Timeouts may be associated with a matching subscription support service, but even these services guarantee operation for at least a year. The tools are generally restricted to a particular vendor's target hardware, but this varies depending on the supplier and the kit.
Unfortunately, there's no standard naming convention for either the kind of kit or the level it's designed to reach. Likewise, a wide range of quality affects how well and how quickly a designer can reach a particular plateau.
Why should you check out a kit? Well, for one, it can help you to get a head start on product development. Also, it can become like a software development platform that turns out to be less expensive that an actual product. It can further assist you in learning about a new platform for educational purposes or for a comparative evaluation.
Kits are a great way to keep abreast of the latest technology. They're used in schools and universities as part of embeddedsystemdevelopment curricula. Companies also have their reasons for offering kits. For instance, they might be showing the capabilities of a new technology like ZigBee. Or they may be trying to garner new developers and convince them to migrate to their platform. Overall, they're attempting to boost demand for the underlying product.
Keep in mind a number of issues while looking for a kit. There's usually a major difference in functionality between kits that use serial/USB software monitors versus JTAG for debugging and flash programming. Also, make sure you understand any limitations on the support software, such as time limits, code-size limits, and debugging limitations.
OPEN SOURCE GNU tools are the foundation of OSS. Richard M. Stallman, president of the Free Software Foundation, started GNU. He also provided many of its tools and developed GPL (General Public License). GNU tools like the gcc compiler form the basis for many software tool suites found in development kits.
Another key addition to OSS is the Eclipse integrated development environment (IDE) (see "Anatomy Of An IDE" at www.elecdesign.com, ED Online 3376). This has moved the sometimeslimited OSS graphical development tools to the premiere platform in use by a range of real-time operating-system (RTOS) and developmenttool vendors as the basis for their own products (e.g. Accelerated Technology, LynuxWorks, Monta Vista, QNX, and TimeSys).
Open source isn't limited to software. Analog Devices distributes hardware designs like the Stamp board (Fig. 3). The Stamp integrates the company's Blackfin, and the board targets a customized uCLinux distribution. Compare this board to Analog Devices' CrossCore offering.
The CrossCore package features more on-board peripherals. It also includes significantly more internal and third-party support. Plus, it comes bundled with a copy of Analog Devices' VisualDSP++ development tools, versus the GNU tools for the Stamp. Which is better? It depends on a variety of factors, from the pocketbook to the developer's experience to the long-range use of the kit. As with most kits, no one kit fills all requirements.
Almost every microcontroller family-has one or more kits available from the vendor or third parties. Thus, hundreds of kits are available. Renesas, Samsung, and STMicroelectronics produce dozens of chip families with a wide range of third-party kit support, and they represent just three of the many vendors out there.
Specialized applications further inflate the number of options. Take for example Microchip's Mechatronix board, which targets motor control (Fig. 4). It highlights Microchip's PIC product line and includes two different types of small motors. The board also can be connected to external motors. Then there's Zilog's motor-control solution, which targets brushless dc (BLDC) motors (see "Smart Motion Makes For A Smarter Design," ELECTRONIC DESIGN, p. 41, Oct. 27, 2005, ED Online 11294). It can provide sensorless speed control.
Low-cost solutions don't necessarily translate into lowquality tools. In fact, even complex areas like motor control are leading to bundled tools that simplify the design and evaluation process. Zilog has a graphical application that provides-custom motor-control applications based on parameters-from the developer, such as the type of motor.
With ZigBee being such a hot topic, the large amount of available kits should come as no surprise (Fig. 5). Ember, Freescale, and Silicon Labs kits illustrate the range of solutions that developers will have to contend with.
Ember's kit includes half a dozen boards. (Hey, a single Zig-Bee module is pretty useless.) The boards include an Ethernet connection, so units can serve as gateways. It also enables Ember to provide a very sophisticated wireless management and monitoring system. It's one of the most expensive kits, designed as a highend development solution for companies looking to commit to ZigBee.
The Freescale evaluation kit resides at the other end of the spectrum. Designed to highlight the capabilities of Freescale's offering, it can be used simply as a demo kit with a pair of boards or as a midrange development tool. An on-board antenna keeps costs down. Meanwhile, Silicon Labs' solution sits in the middle, with six boards hosting a single-chip solution.
MODULE KITS Some of the ZigBee kits use plug-in modules. They offer a way to incorporate development hardware into a final solution. Of course, many companies simply target modules as a solution, while chip vendors often target custom hardware.
Rabbit Semiconductor has had success selling modules (Fig. 6). Designers can buy the 8-bit Rabbit processors, but most developers simply use the modules. The plug-in approach serves up a number of benefits, including the ability to easily change the module used in a product from a less expensive, less functional unit to a more expensive, more functional unit.
Also, Rabbit Semiconductor isn't alone. There's a host of other solutions, from the Java-based Systronix TStik2 built with a Maxim Integrated Products processor (see "Tiny Stick Runs Java, CAN, Ethernet, 1-Wire, I2C, And SPI," ELECTRONIC DESIGN, p. 66, Nov. 7, 2005, ED Online 11324) to the Gumstix Intel Xscale ARM-based processor. Even board vendor Kontron has a wide selection of x86-based modules.
FPGA KITS Microcontroller-based kits are the most numerous, but analog and FPGA solutions are available, too. They tend to have a more limited audience and are often more expensive. Likewise, the learning curve usually is steeper. Getting to Plateau 3 may take days to weeks instead of hours.
Altium along with FPGA vendors Altera and Xilinx have some interesting solutions, though they are not exclusive. Note that these companies are feeling the demand for faster evaluation in addition to simpler and less expensive tools. One sample response is Xilinx's Spartan-3 Starter Kit, which costs $99. At the other end of the spectrum is Altium's Nanoboard-NB1. It contains plug-in modules for FPGAs and complex programmable logic devices from a number of vendors.
REFERENCE DESIGNS Looking for a product out-of-the-box? You may be looking for a reference design. They tend to be different from conventional kits, but their end purpose is usually the same—to get developers to use the vendor's product.
Be it a reference design, demo kit, or evaluation kit, developers have a wide range of choices to get hands-on experience at a reasonable cost.
NEED MORE INFORMATION?
Maxim Integrated Products
Free Software Foundation
Green Hills Software