Developer Documentation
PATHHardware Documentation > Original Power Mac G3 Computers Developer Note


PCI Expansion Slots

The Power Macintosh G3 logic board uses the industry-standard peripheral component interconnect (PCI) bus for an I/O expansion bus. The PCI bus is a 32-bit multiplexed address and data bus. The PCI expansion slots have a 33.33 MHz clock frequency.

PCI I/O expansion cards are mounted vertically in PCI expansion slots on the main logic board.

A total of 15 watts of power is provided for each of the PCI expansion slots. Both 5 volts and 3.3 volts are supplied; the total power consumed by both voltages must not exceed the 15-watt maximum.

The Power Macintosh G3 logic board requires that PCI cards use the 5-volts signaling standard described in the PCI Local Bus Specification , Revision 2.1.

The logic board accepts standard 6.88-inch and 12.283-inch PCI cards as defined by the PCI Local Bus Specification , Revision 2.1. The cards are required to use the standard ISA fence described in the specification.

The PCI slots support all the required PCI signals and certain optional PCI signals. The PCI slots on the logic board do not support the optional 64-bit bus extension signals or cache support signals.

For more information about the PCI expansion slot, refer to Designing PCI Cards and Drivers for Power Macintosh Computers.


© 1998 Apple Computer, Inc. - Revised 8/13/98