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PC catting microcontroller: Come in, please!
If you purchase a microcontroller without an embedded interpreter, you need to also buy (or make) a hardware-programming module. The hardware module provides a physical link between your computer and the microcontroller.
You can use most commercial modules to program several microcontrollers that come from the same manufacturer, so look for that feature. It doesnít make sense to get a hardware module that programs just one specific microcontroller because you lock yourself into just that chip.
The price tag for hardware modules runs from just a few dollars to $100 or more. You can also build your own module, but most first-timers opt for a ready-made one to save time and hassle. Take a whack at building your own module after youíve gained a little experience with microcontrollers.
Figure 13-3 shows a typical commercial hardware-programming module. This particular module also provides built-in buttons and lights to help in developing applications You donít have to use the added development features just to program a microcontroller, but they can be nice to have, and donít usually add much to the price of the module. You plug the chip into a socket in the module and attach a cable to your PC. Most, but certainly not all, modules come with at least one editor that you can use to write your programs. If the module you buy doesnít have a programming editor, you need to get one. team LinG - live, Informative, Non-cost and Genuine !
You can use a hardware module like this one to program microcontrollers.
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Explaining how to select a programming module and programming editor for a given microcontroller goes way beyond the scope of this book. You can choose from dozens of options, and the marketplace changes all the time. Your best bet is to contact the manufacturer of the microcontroller that you want to use and ask for recommendations.
Microcontrollers That Stand Out from the Rest
Of the dozens of brands of microcontrollers, two stand out as ideally suited for hobbyists. The following sections give you a rundown of these microcontrollers. Only you can decide which one fits you and your projects.
Introducing the BASIC Stamp
The BASIC Stamp is one of the best-known and most widely used microcontrollers for students and hobbyists. That popularity doesnít come from its lightning speed or a gaggle of features; it gets its popularity because it was one of the first microcontrollers to include an embedded interpreter.
term LinG - live, informative, Non-cost and Genuine !
288 Part V: A Plethora of Projects
The BASIC Stamp derives its name from its built-in BASIC language and its postage-stamp size (well, a kind of large stamp). You can find out more about the BASIC Stamp by visiting www.parallax.com.
The BASIC Stamp comes with some of the best documentation that you can find for a microcontroller. If youíre just starting out, you canít go wrong with the BASIC Stamp because of all the tutorials, how-toís, references, and project ideas that you can easily find for it.
Tasting different flavors
You probably think a BASIC Stamp is . . . well, basic. But the BASIC Stamp comes in varieties ó 1, 2, SX, and a slew of others. These versions differ in features and, in some cases, the embedded programming language. Parallax sells a version of the BASIC Stamp, called the Javelin, which has the Java programming language embedded rather than BASIC, for example.
The BASIC Stamp 2, or BS2, is one of the most popular of the gang and the one that we recommend when youíre just starting out. The BS2 comes on a single 24-pin chip, as you can see in Figure 13-4. This one chip is actually a carrier: it contains a lot of little integrated circuits and other components, such as extra memory and a voltage regulator.
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The venerable BASIC Stamp 2 allin-one microcontroller.
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Chapter 13: The Exciting World of Microcontrollers 289
Adding a development board
Although you can use the BS2 chip as-is, most beginners enhance it with a project board. Parallax sells several boards that you can choose from. One board, cleverly named the Board of Education (or BOE), has a larger capacity voltage regulator built in, as well as extra connectors for hooking things up to it. The BOE, which you can see in Figure 13-5, also includes a little solderless breadboard right on it so that you can try out different circuits. Very handy!
The Parallax Board of Education.
You can buy the BOE with or without a BS2 chip. You can also find versions that you connect to your PC using a serial or USB cable. If your computer lacks a serial port ó if you have a late-model laptop, for example ó you have to get the USB version.
Don't forget the programming software
You have to get specialized software for programming any version of the BASIC Stamp. You can get the software for free. It comes included as part of a BASIC Stamp starter kit. You can also download it from the Parallax Web site. You can find several versions of the software for use with MS-DOS, Windows 98 or later, Macintosh, or Linux.