Sun Microsystems Sun Blade 100, Service Manual

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C-10 Sun Blade 100 Service Manual • October 2000
C.4 Clocking
C.4.1 Clock Generation
There are four clock domains in Sun Blade 100. The domains are CPU, SDRAM, PCI,
and miscellaneous clocks.
All the clocks in those four domains are generated from clock synthesizers or
dedicated crystals on the motherboard except SDRAM clocks, which are generated
by the CPU.
TABLE C-1
lists all the clocks present on the system. Each of the clocks listed is
generated by the clock generator or a dedicated crystal.
TABLE C-1
Clock Frequencies
Component Clock Frequency (MHz) Source Description
CPU CLKA 125 ~ 350 Clock Generator LVPECL
CPU CLKB 125 ~ 350 Clock Generator LVPECL
CPU PCI_REF_
CLK 66.66 Clock Generator Core PCI clock
CPU PCI_CLK 33.33 Clock Generator PCI clock
SouthBridge PCI_CLK 33.33 Clock Generator PCI clock
SouthBridge OSC32KI/ 32.768KHz Dedicated Crystal Real Time Clock
SouthBridge USB_CLK 48.00 Clock Generator USB Clock
SouthBridge OSC14M 14.3182 Clock Generator Reference clock
Graphics Chip Clk 29.499 Dedicated Crystal Video clock
Graphics chip PCICLK 33.33 Clock Generator PCI Clock
PCIO-2 PCICLK 33.33 Clock Generator PCI Clock
PCIO-2 USBCLK 48.00 Clock Generator USB Clock
IChip2 PCICLK 33.33 Clock Generator PCI clock
PCI Bridge PCICLK 33.33 Clock Generator PCI clock
AC97 XIN 24.576 Dedicated Crystal CS4297 Clock
1394 PHY XIN 24.576 Dedicated Crystal FW802 Clock