Although the PICAXE has limitations from the viewpoint of professional applications, PICAXE platforms are pretty much ideal for the kind of stuff David gets up to in his workshop.
As you are no doubt aware, the editor of MCU Designline -- the illustrious Max Maxfield -- is currently on a quest to learn the Arduino. In one of his recent blogs -- It's Crunch Time for Me to Learn the Arduino -- Max said the following:
My most recent fling was playing with a PICAXE controller board based on a Microchip PIC; I programmed it using a form of BASIC. The PICAXE was a lot of fun, but it's too low-level for what I need.
This gave me some cause for concern, as I had coincidentally just ordered a small PICAXE kit as part of a special offer by one of my suppliers. I raised this as a comment in Max's column, wondering if I'd done the right thing. In response, Max went to some lengths to justify his own interest in the Arduino, but he also said: "...for just messing around with your own projects, I think you will love the PICAXE."
Before we proceed further, let me give you a little background. I did a bit of microprocessor programming in the "good old days" -- the 80s and 90s -- mostly on the 8080 and the Z80. My life then shifted more into telecom, where I work to this day. But modern telecom has grown increasingly divorced from the electronics that supports it, and I have felt a strong desire to get back to the electronics side of things. My recent programming has been mainly on things like PABXs and Procomm at work, so I took the bull by the horns and ordered the PICAXE kit.
I have done a lot with BASIC in the past, including the old Sinclair ZX81 and Spectrum, and I also programmed a terminal emulator in Qbasic. The end result is that I got pretty good at BASIC, so I thought the PICAXE would be a good starting point for my foray into microcontrollers. I'd also like to learn C at some stage, but for the moment I wanted something I could get to grips with quickly for a few ideas I wish to "mess around with," as Max puts it.
On top of everything else, Max then asked me if I would write a couple of blogs on my experiences with the PICAXE system. Having Max nipping at your heels for blogs to post is a fine incentive to get going and do something, so I jumped at the chance.
The PICAXE world consists of various Microchip MCUs that have been pre-programmed with a bootstrap loader that enables very easy programming without an expensive programmer. These are coupled with a development environment that lets you write programs in a variation of the BASIC language. The available chips range from the 08M2, which has 8 pins and 6 I/O lines, to the 40X2, which has 40 pins and 33 I/0 lines.
Programming (on PICAXE's own boards) is performed through a 3.5 mm stereo type jack connector like those used on MP3 players. All the chips offer analog-to-digital converters (ADCs), pulse width modulation (PWM), I2C and serial connections, and touch interfaces, as well as standard digital I/O. The larger ones also offer SPI and a couple of other options. This is all pretty tasty to someone whose last hands-on experience was with systems that needed vast arrays of chips to achieve all the above, though I have kept a hands-off eye on microcontroller technology and pretty much knew what to expect.
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