tashtari
PIC Whisperer
I'd take a look at Appendix C of the ADB I/O manual, it details the ADB protocol used by the ADB I/O and should help you write a function for controlling port B.
You can find the manual here: https://web.archive.org/web/1998050...80/BeeHive/ADB_IO/Downloads/ADB_IO_manual.pdf
You can find the manual here: https://web.archive.org/web/1998050...80/BeeHive/ADB_IO/Downloads/ADB_IO_manual.pdf