Compaq EN Series 3.2 PROCESSOR/MEMORY SUBSYSTEM

Chapter 3 Processor/Memory Subsystem
Compaq Deskpro EN Series of Personal Computers
Desktop and Minitower Form Factors
Third Edition - September 1998
3-2
66-/100-MHz
Mem. Data Bus
Mem. Addr.
Graphics
Subsystem
3.2 PROCESSOR/MEMORY SUBSYSTEM
The subsystem features an Intel Pentium II or Celeron processor with 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.
Figure 3–1. Processor/Memory Subsystem Architecture
The processor is mounted in a slot 1-type connector that facilitates easy changing/upgrading.
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 443BX supports SDRAM,
EDO, FPM, and ECC DIMM modules. Thr ee DIMM sockets allow the system memory to be
expanded to 384 megabytes.
Processor
(in Slot 1)
33-MHz 32-Bit PCI Bus
Optional module
32-MB
DIMM DIMM
J1 J2
System Memory
66-/100-MHz
64-Bit Host Bus
North
Bridge
(82443BX)
Cntl
DIMM
J3
66-MHz
32-Bit
AGP Bus