C.1.2.1 U2P ASIC

The UPT-to-PCI bridge (U2P) ASIC controls the PCI buses. It forms the bridge from
the UPAbus to the PCI buses. For a brief description of the U2P ASIC, see Section
C.1.12 “ASICs” on page 271.

C.1.2.2 Symbios 53C876 SCSI Controller

The Symbios 53C876 SCSI controller provideselectrical connection between the main
logic board and the internal and external SCSI buses to the PCI bus. The Symbios
controller is two SCSI controllers on the same PCI slot. Controller “A” is used to
interface to internal devices. The second controller,controller “B,” is used to interface
to external devices.

C.1.2.3 PCIO ASIC

The PCI-to-EBus/Ethernet controller (PCIO) ASIC bridges the PCI bus to the EBus,
enabling communication between the PCI bus and all miscellaneous I/O functions,
as well as the connection to slower on-boardfunctions. The PCIO ASIC also embeds
the Ethernet controller.
C.1.3 UltraSPARC II Processor
The UltraSPARCII processor is a high-performance, highly-integrated superscalar
processor implementing the SPARC-V9 64-bit RISC architecture. The UltraSPARC II
processor is capable of sustaining the execution of up to fourinstructions per cycle
even in the presence of conditional branches and cache misses. This sustained
performance is supported by a decoupled prefetch and dispatch unit with instruction
buffer.
The UltraSPARCII processor supports both 2D and 3D graphics, as well as image
processing, video compression anddecompression, and video effects through the
sophisticated visual instruction set (VIS). VIS provides high levels of multimedia
performance, including real-time video compression/decompression and two streams
of MPEG-2 decompression at full broadcast quality with no additional hardware
support. The UltraSPARCII processor provides a 2-Mbyte ecache, with an 300-MHz
operating frequency.
UltraSPARCII processor characteristics and associated features include:
SPARC-V9architecture compliant
Binary compatible with all SPARCapplication code
Multimedia capable visual instruction set (VIS)
Multiprocessing support
254 Sun Enterprise 220R Server Service Manual ♦January 2000, Revision A