System Clock Distribution - Compaq EN Series Technical Reference Manual

4.5

SYSTEM CLOCK DISTRIBUTION

The system uses a Cypress CY2280 or compatible part for generation of most clock signals.
Table 4-16 lists the system board clock signals and how they are distributed.
Table 4–16. Clock Generation and Distribution
Clock Generation and Distribution
Frequncy/Signal
66, 100 MHz
(CPUCLK) [1]
66 MHz
48 MHz
33 MHz (PCICLK)
14.31818 MHz
14.31818 MHz
8.33 MHz (BCLK)
32.77 KHz
NOTE:
[1] Depending on processor speed (refer to
Chapter 3, "Processor/Memory Subsystem").
Table 4-16.
Source Destination
CY2280 Processor, 82443 N. Bridge
North Bridge ATI Rage Pro Controller
CY2280 82371 S. Bridge, 87307 I/O Cntlr.
CY2280 PCI Slots, 82371 S. Bridge
Crystal CY2280
CY2280 South Bridge, ISA slots
South Bridge ISA slots
Crystal 82371South Bridge,
87307I/O Cntlr.
Compaq Deskpro EN Series o Personal Computers
Net PC and Small Form Factor Models
First Edition - June 1998
Technical Reference Guide
4-27