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.