Started work on this but didn’t have much time to finish it.
It’s a Teensyduino port of the multiboot serial converter for use on the Gameboy Advance.
Edit 1/11/10: Resumed work on this. Figured it didn’t work because I used the delayMicroseconds function rather than a hardware timer which didn’t give enough resolution. I also fixed the passthrough problem. Once I finish learning how to use hardware timers, I shall get back to you.