Technical Information 1-3
PCI Local Bus
The 32-bit industry-standard PCI bus is a highly-integrated input/output (I/O) interface that
offers the highest performance local bus available for the Pentium II processor. The PCI bus
supports burst modes that send large chunks of data across the bus, allowing fast displays of
high-resolution images.
The high-bandwidth PCI local bus eliminates data bottlenecks found in traditional systems,
maintains maximum performance at high clock speeds, and provides a clear upgrade path to
future technologies.
The PCI bus contains two embedded PCI devices: the PCI local bus IDE interface and the
PCI video/graphics controller. The PCI bus also contains a connector for attaching the bus
expansion board.
Expansion Bus
The expansion bus contains one ISA slot, three PCI slots, one PCI/ISA slot, and one AGP
video slot. The PCI ISA IDE Xccelerator chip (PIIX4E) provides the logic that enables the
ISA bus functions. With 24-bit memory addressing, a 16-bit data path, and an eight MHz
clock, the ISA bus is designed to support all peripherals compatible with the IBM
AT
standard. For PCI functions, the Xcelerator chip provides 32-bit memory addressing, 32-bit
data path, and a 33-MHz clock speed.
BIOS
The BIOS (Basic Input Output System) is stored in the Intel 28F002 Flash EPROM. The
Flash EPROM is reprogrammable and allows fast, economical BIOS upgrades.
The system memory map in shown in Table 1-2.
Table 1-2 System Memory Map
Memory Address
Size
Function
100000-18000000
383 MB
Extended Memory
E8000-FFFFF
96 KB
System BIOS
E0000-E7FFF
32 KB
System BIOS (Available as UMB)
C8000-DFFFF
96 KB
Available high DOS memory (open to ISA and
PCI bus)
A0000-C7FFF
160 KB
Video memory and BIOS
00000-9FFFF
640 KB
Conventional memory
