I have a handful of AVR chips that I'm using in various projects (including WOSP). You use the SPI interface to upload the software to the chip's flash memory. I wrote a custom program on the Arduino that would read in Intel S-records and push the program onto the chip. I hoped to simply send the programs a file at a time to the chip. Didn't work. There was no hardware handshaking between the USB Arduino and the computer, so it would fill the buffer and then hang. No fun. I tried adding xon-xoff control but couldn't get that working either. I could put the programs in using Hyperterminal, one line at a time. That got old before it was even new. I decided to clone the AVR910.

It wasn't hard to do, I just read through the published source from Atmel and converted it to C for the Arduino. Once I had it sending and receiving characters I got AVRDUDE and started debugging. I had some initial problems because I tried to tell avrdude I had an AVRISP. I didn't, I had AVR910. It took a few night's hacking but I got to where I could read and right EEPROM and Flash on the target chips. The last problem I fixed was a byte order thing with sending an address. Seems that avrdude sends the programs one byte at a time, preceeded by the address. So each time I would get the address but in the wrong byte order. I swapped it around and suddenly it worked.

My targets are ATtiny13, 15, and 2313. The tiny13 isn't officially supported by avr910, so I just assigned it an ID of 1 and it works. I haven't tried the tiny15 chip yet, but the programmer works for tiny13 and tiny2313.

So look for more AVR projects from me in the near future!