I'm trying to get my PC to communicate with an ATTiny45 using the USB cable that came with my Nerdkit. Basically what I want to do is to control a lava lamp from my PC. I found a nice relay that can do that. So what I want to do is to send a 1 over the USB cable to turn the lamp on and a 0 to turn it off.

This is pretty easy on the ATMega168 using the uart-library provided with the Nerdkit. However as I understand the ATTiny does not support UART, so I can't use that. I tried to understand something called USI, didn't really get it though.

Would be great if someone could explain to me how to do what I want to do.

Thanks.