I'm looking for some cheaper alternative to the Basic Stamp, some kind of microcontroller:
where I can write the program in Basic, and download it to the controller to test it out.
reprogram it again if needed (eeprom, obviously)
A byte or two of programmable i/o lines
does not need a $1000 development system to get started, maybe just a dongle on a serial cable or something.
cheap or free compiler.
OK, it sounds like what I need is...a Basic Stamp! But they are so damn $$$. I design interactive art pieces, like colonies of interactive "insects", I don't want to pay $50 bucks apiece for a brain to read some sensors and make some lights blink...
Hi, Eric. If you're looking for a somewhat lower cost, ultra-simple "stamp-like" IC, try the PICAXE.
The PICAXE is based on the PIC, like the original BASIC Stamp. You buy just the IC itself instead of a small circuit board or hybrid module like the Stamp (meaning you'll have to put a ceramic resonator, a 78L05 voltage regulator and a couple of caps on a perfboard with the IC to make it work). However, it does do BASIC, and your installed cost is a lot less than the Stamp.
I haven't had a chance to play with the PICAXE myself, but I've looked at the docs, and heard from people who've had satisfactory experiences with them. They're slower, and they have a somewhat more limited instruction set, but, again, they're cheap. Pick the one you want to start with (if you're looking at Stamps, you'll probably want the 18 pin PICAXE), and get the development kit to start. For the simple bit-banging I/O stuff and timed control loops, it should do as well as the Stamp.
If you're in the States, you'll have to order from England. They don't have any distributors on this side of the pond, AFAIK. Also, they're priced in pounds (you can use a credit card, shipping is somewhat slow, and be sure to look again at the exchange rates before you buy to avoid a shock -- the USD don't buy what it used to).
Questions of this type usually get a friendly reception on s.e.b.
Hi, Chris. I think this is an excellent suggestion. I haven't used them, either. But I had looked at them some time ago and felt the price was reasonable.
Another thought crossed my mind, though. And I really don't know how well beaten the path might be. Maybe not at all, and that would preclude it being useful here. But there was an MCS BASIC-52 for the 8031/32 and I'm wondering if anyone has tried to port it over to a Cygnal or Atmel incarnation. If so, the tools for either would be inexpensive, I believe.
There may also be some free BASIC compilers and almost certainly some that are commercial, but free when used for tiny programs. And this sounds like a tiny program kind of thing.
Just some thoughts banging around in me from your response.
"Eric Griswold" wrote in message news:cp8mf8$oco$ firstname.lastname@example.org...
You have to start by understanding what the 'stamp' is. It comprises either a PIC, or similar processor, with it's ROM, containing a fairly large interpreter. Attached to this, are a crystal/resonator to provide the clock, and an EEPROM to contain the 'code'. This is all built onto a small 'carrier' board, which then brings the I/O lines to the outside world. This obviously involves quite a lot of cost (the royalties for the interpreter, the board, and the support parts). Hence the price. The cheapest way to give a 'similar' operation, is to use an in-circuit programmer to program a PIC itself directly, and write your program using a Basic (if this is the language you are determined to use). There are some free Basic's on the web. For instance, 'Crownhill associates' do one for certain chips:
Did a design to emulate the Stamp. But this is limited to only two now rather 'obsolete' chips. If you are prepared to try another language, there are several free 'C' compilers on the web. In either case, the 'support' needed round the chip will then depend on what you want to do. The 'simplest' situation will be where the clock rate is not terribly critical, and you may well then be able to use the interal RC oscillator built into some of the PICs. However if you are intending to support asynchronous serial comms, this is not really a 'wise' route, so a crystal/resonator will be needed. With most of the flash based PICs, you won't need external memory, since the code can be reprogrammed into the chip itself, and changed as needed.
Neither the Pixaxe08, 08M, 18, 18A, or 18X require a resonator. They have built in oscillators. The 28's and 40's do.
I started out with the Stamp, but was turned off by the high price for small projects. The Picaxe, especially the 08 and 08M, are great to replace circuits that required several logic chips to impliment.
The exchange rates, $USD vs. GBP, don't make me happy, but they are still relatively cheap. And the delivery time has been surprisingly quick.
For the micro, I would strongly suggest that AVR family of Atmel.
A wide variety of on-board options (i.e. RTC, A to D converters, PWM, SPI, etc.) and and 'expensive' chip is less than $10 US. Fast and powerful.
As to the programmer, look at BASCOM.
This is a BASIC compiler designed for the AVR family of micros. You can download the demo software for free or buy the registered version for about $80 US. The difference between the demo and the registered version is the size of programs you can generate. TONS of support, too.
To show how simple the software is, here is a program that will read all 8 ADC channels on the AT90S8535 and display the results on your computer screen.
$regfile = "8535def.dat" Config Adc = Single , Prescaler = Auto Start Adc Dim W As Word , Channel As Byte Channel = 0 Do W = Getadc(channel) Print "Channel " ; Channel ; " value " ; W Incr Channel If Channel > 7 Then Channel = 0 Loop End