What do you guys know about AVRs?

[bic]

I've got a lot of bad circuit cards I've been scrapping for their aluminum backs, and each has an AtMega64L, among other fun components. I've been harvesting the parts with a hot air gun, and assuming I haven't cooked the poor things I'd like to do something with them. Nothing amazingly spectacular like DIY game systems or video players, just starting with things like text POV displays and stepper motors.

I've already read a few tutorials off electronics sites like ladyada.net and Evil Mad Scientist, but they're either missing the programming parts, or are written for people who already know what the Heck they're doing. "Just write your program plug this in there and then patch the semitransducer through the flux capacitor and when it hits 700 sell; see wasn't that easy?

" (Kind of like this.) All I know right now is they can be programmed while still in the circuit with a special 6 pin cable and programmer, and that they're mostly compatible with code written for lesser models. At this point I know far more about soldering them into place than actually making them do something.

The biggest missing piece is the programmer. From what I can tell, this $15 model from Sparkfun should do the job?

Anybody know of some decent tutorials for people starting from square one?

(Crossposted from BH)

 

[oinquer]

while i cant help you much with AVR's im glad to see another bud going into chip programming, i use microchip's PIC's and TIBBO products in my projects.

they dont guarantee that programmer works with other AtMega's other than the ATmega168 and the ATmega328, but it should as they say.

 

[XCVG]

You can actually ghetto together a programmer from a parallel cable, but I don't know how well that will work. It also requires an oldish computer that actually has a parallel port.

 

[Hermaphroditus]

You can buy PCI Parallel ports. My grandpa bought a few for his computers at his office because he plugs a testing machine for circuits he made into his computer.

 

[bic]

Thanks! That's a start anyway.

Whipping up a programmer for the cost of a 25 pin D-sub connector sounds like it will work well enough for now. (e: As it tuns out that price is $0 because another board has one! ) One benefit to working in IT is there's always a pile of junk computers to pick through. (So many Dell SX270s with bad caps... ) I'm sure there's something with a parallel port around here somewhere. The only problem will be soldering to the tiny chip packages, but I think 80 strand IDE cable wires are thin enough to not bridge.

Turns out some of the boards have Mega1281s. (The Mega64Ls greatly outnumber them though.) Not sure what the differences may be besides amount of onboard flash storage, but bigger numbers are usually better right?

From what I've read, higher-trim AVRs can generally run code written for lesser models; is there anything special about the Arduino platform besides the standardized connectors and bootloader? Would all that ATiny stuff port over fairly easily?

 

[XCVG]

Arduino is designed for ATMega328 and ATMega168. It would be possible to recompile code for different chips, fairly easily I think. I recommend you ask on the Arduino forums.

 

[robm]

AVRs are great, and what's better is that "commercial" programmers don't cost a whole lot, and operate by USB. I would go with this over a programming cable:

http://www.adafruit.com/index.php?main_ ... d6e61bbb1b

The DAPA cable (the cable you'd build) works but for $22, why not go with something that works with any computer.

As far as code migration between processors, it's fairly easy to go between one model to another with some minor changes (or no changes, in some cases.) The AVR SDK (WinAVR) supports either C or Assembly, which is nice.

 

[dsv101]

I love me some AVR's more specifically there atmega328. I like this because it can be purchased with the arduino boot loader on it, which makes coding a bit easier. All you would need to do is program the chip on an arduino board (i only use the board as a code loader and for prototyping) then you can just solder your circuit to a custom pcb, or just wire everything directly. Also the atmega328 has a good amount or usable ram, and is pretty powerful.