Monday, June 10, 2013

Little Wire

As usual, I've been all sorts of busy, with little time to blog about it.

I did recently score a cache of small, nay, tiny AVR chips recently, and my wife had an interest in making something with them (maybe I can get her to guest-blog about it). Anyways, I was at a local hacker meeting this evening and the subject of programming Attinys came up. As it happens, I just built a couple of Little Wire devices, but couldn't remember the name at the time. For some reason, the name makes me think of Jimi Hendrix. It's an Attiny85 based device that combines USBTiny with VUSB. The really cool think about it is that you can make an AVR programmer for roughly $3 USD worth of parts (and considerably more labor, but it's not work if you love it right?)

Here's one of my rat-nested Little Wire AVR-ISP devices:
Well she's walking through the clouds....

The Attiny 85 has a neat feature that I had overlooked until I built this in that it has a built in PLL that lets you run the system off the internal RC oscillator at around 16Mhz. Many other AVR's lack that PLL, and can only run at 8Mhz maximum without an external crystal.

I like saving my AVR Dragon for when I need to debug or do JTAG.

The easiest way to use Little Wire is with avrdude (I copied the avrdude executable and conf files from the arduino instalation into thier own folder). I then run:

avrdude -c usbtiny -p t84 -U flash:W:<path to my hex file>:i

To burn AVRStudio built hex files into (in the above case) an Attiny 84 chip.