Bootbus - Sun Microsystems Sun Blade 1000 Service Manual

Reset
CPU
Request
Gnt
System Clock
Synthesizer
UPA Clock
Synthesizer
FIGURE C-9
C.1.6.1 BootBus Controller (BBC) ASIC
The BootBus controller provides access to the boot PROM by bridging the Sun
CrossBar Interconnect BootGroup signals (the BootBus) and the EBus. The boot
PROM connects directly to the EBus.
The PCIO-2 is also a master on EBus. Full arbitration between the PCIO-2 and the
BBC controls access to the EBus. The EBus is accessed from the BBC only during the
boot sequence that is, during the execution of POST and OpenBoot PROM.
Note – When the system is running Solaris software, the kernel has no knowledge
of the BootBus space.
C-24 Sun Blade 1000 and Sun Blade 2000 Service Manual • January 2002

BootBus

BootBus
Controller
ASIC
EBus
Energy
®
Star
Boot
PROM
(Flash
Memory)
Sun Blade 1000 and Sun Blade 2000
Reset
CPU
Request
Gnt
8
6
Serial
SuperI/O
Lines
Controller
Floppy
Boot Structure
TDO
TDI
JTAG
TMS
SCL
I2C
SDA
USB
PCIO-2
ports
Parallel Port