Even though PCI is really common it usually doesn’t see experimentation by amateurs because of its high performance nature. ChaN decided to build a system to demonstrate that PCI is within the reach of hobbyists. He does this with just 1 GAL, 2 identity comparators, and 4 latches. To pull this off a couple design rules have to be violated. For example: There is no configuration register so the target address has to be set with DIP switches. Something you would never see in real life. ChaN has been posting electronics projects for quite a few years and his site is well worth further investigation.