Processor/Memory Subsystem; Figure 3-1. Processor /Memory - Compaq EN Series Technical Reference Manual

Chapter 3 Processor/Memory Subsystem
3.2

PROCESSOR/MEMORY SUBSYSTEM

This system features the Intel Pentium II processor, the North Bridge (82443BX), and either 32
or 64 megabytes of system memory (Figure 3-1). The 64-bit Host and memory buses operate at
either 66- or 100-MHZ depending on the speed of the processor. The 32-bit PCI bus operates at
33-MHz.
66-/100-MHz
64-Bit Host Bus
66-MHz
32-Bit
AGP Bus
Graphics
Subsystem
Optional module
Figure 3–1. Processor/Memory Subsystem Architecture
This system uses a slot 1-type connector that facilitates easy changing/upgrading of the processor.
Replacing the processor may require reconfiguring DIP switch SW1 to select the correct bus
frequency/core frequency combination. Frequency selection is described in detail later in this
section.
The North Bridge (82443BX) provides Host/memory/PCI bridge functions and controls data
transfers with system memory over the 64-bit memory data bus. The 82443BX supports SDRAM,
EDO, FPM, and ECC DIMM modules. Two DIMM sockets allow the system memory to be
expanded to 256 megabytes.
3-2 Compaq Deskpro EN Series of Personal Computers
Net PC and Small Form Factor Models
Pentium II
SEC Cartridge
(in Slot 1)
Cntl
66-/100-MHz
Mem. Data Bus
North
Bridge
(82443BX)
Mem. Addr.
33-MHz 32-Bit PCI Bus
First Edition - June 1998
System Memory
J2
J1
32-MB
DIMM DIMM