Just wondering if it's feasible to "easily" make ATtiny85's into AVR programmers?
I'm making a little AVR programming box for our learning centre. I'd much rather use our centre's extreme excess of ATtiny85's for a buck each rather than use an actual Arduino.
Decent ISP programmers go for about $8 on eBay. There's some cheaper ones, too, but I never tried them.
With a few cheap programmers you could put your pile of Tiny85s to use as little programmable chips. Teach people to build stuff with them.http://arduino.cc/forum/index.php/topic,148155.0.html
I've also read that ATtiny's do not actually have native SPI
The have "USI" which is hardware support for a number of serial interfaces like SPI, I2C, etc. You have to add a tiny bit of software to make it work as SPI.