The Apple IIgs has a split personality. Most of the machine runs at a ~1MHz clock rate, keeping compatibility with earlier Apple IIs. Some components, however, can be decoupled and run at a faster rate. The FPI, or Fast Processor Interface, is the chip responsible for coordinating the interactions between these personalities. In this session, Daniel “Krüe” Kruszyna includes a high level overview of the FPI’s responsibilities, along with a detailed look at some particular cases, using signal measurements obtained from a real Apple IIgs.

Recorded July 22, 2011, by Ken Gagne and made available by KansasFest, Inc., under an Attribution-ShareAlike 3.0 Unported (CC BY-SA 3.0) Creative Commons license.