Asics - Sun Microsystems Sun Ultra 60 Service Manual

C.1.12.5 SCSI ID Selection
The motherboard host adapter is assigned the SCSI identification of 7 for both ports.
The two internal drives attached to the SCA-2 connectors have a SCSI identification
of 0 and 1, while the CD-ROM has an identification of 6.
C.1.13

ASICs

The system unit achieves a high level of integration through application-specific
intergrated circuits (ASICs). All ASICs are 1149.1 (JTAG) compliant. The following
ASICs are highlighted and are described in the following subsections:
4 XB9+
4 QSC
4 PCI-to-EBus/Ethernet controller (PCIO)
4 UPA-to-PCI bridge (U2P)
4 Frame buffer controller (FBC)
4 Reset, interrupt, scan, and clock (RISC)
Also included in this section are brief discussions of the SuperIO component.
C.1.13.1 XB9+
The XB9+ ASIC is a buffered memory crossbar device that acts as the bridge between
the six system unit buses. The six system unit buses include two processor buses, a
memory data bus, a graphics bus, and two I/O buses. The XB9+ ASIC provides the
following:
Note -
word is 32 bits, and a doubleword is 64 bits.
4 Six-port crossbar
4 Decoupled memory port; loading and unloading of memory data can take place in
parallel with other operations
4 Burst transfers operate on a doubleword of data per slice
4 A total of eight two-entry first-in-first-out (FIFO) devices for read data storage
4 Power-up safe buses (tristated)
Sun Ultra 60 Service Manual ♦ March 1999, Revision A
C-30
Referred data formats are as follows: a byte is 8 bits, a halfword is 16 bits, a