Sun Microsystems 220R service manual PCI Bus

C.1.2 PCI Bus

The peripheral component interconnect (PCI) bus is a high-performance 32-bit or 64-bit bus with multiplexed address and data lines. The PCI bus provides electrical interconnection between highly integrated peripheral controller components, peripheral add-on devices, and the processor/memory system.

There are two PCI buses. The first bus is a one-slot, 3.3-VDC, 64-bit or 32-bit,

66-MHz or 33-MHz bus. The second bus is a three-slot, 5.0-VDC, 64-bit or 32-bit,

33-MHz bus. Each bus is controlled by the UPA-to-PCI bridge (U2P) ASIC. There are also two on-board controllers, the Symbios 53C876 SCSI controller and the PCI-to-Ebus/Ethernet controller (PCIO) ASIC, on the 33-MHz PCI bus.

Functional Description 253