Appendix c. system address maps, System memory map, I/o address map – IBM Partner Pavilion 6350 User Manual

Page 75

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Appendix C. System address maps

The following charts represent how the hard disk stores different types of
information. Address ranges and byte sizes are approximate.

System memory map

The first 640 KB of system board RAM is mapped starting at address hex 00000000.
A 256-byte area and a 1 KB area of this RAM are reserved for BIOS data. Memory
can be mapped differently if POST detects an error.

Table 1. System memory map

Address range
(decimal)

Address range (hex)

Size

Description

0 K – 512 KB

00000 – 7FFFF

512 KB

Conventional

512 K – 639 KB

80000 – 9FBFF

127 KB

Extended conventional

639 K – 640 KB

9FC00 – 9FFFF

1 KB

Extended BIOS data

640 K – 767 KB

A0000 – BFFFF

128 KB

Dynamic video memory display cache

768 K – 800 KB

C0000 – C7FFF

32 KB

Video ROM BIOS (shadowed)

800 K – 896 KB

C8000 – DFFFF

96 KB

PCI space, available to adapter ROMs

896 K – 1 MB

E0000 – FFFFF

128 KB

System ROM BIOS (main memory shadowed)

1 MB – 16 MB

1000000 – FFFFFF

15 MB

PCI space

16 MB – 4096 MB

10000000 – FFDFFFFF

4080 MB

PCI space (positive decode)

FFFE0000 – FFFFFFFF

128 KB

System ROM BIOS

I/O address map

The following table lists resource assignments for the I/O address map. Any
addresses that are not shown are reserved.

Table 2. I/O address map

Address range (hex)

Size (bytes)

Description

0000 – 000F

16

DMA 1

0010 – 001F

16

General I/O locations, available to PCI bus

0020 – 0021

2

Interrupt controller 1

0022 – 003F

30

General I/O locations, available to PCI bus

0040 – 0043

4

Counter/timer 1

0044 – 00FF

28

General I/O locations, available to PCI bus

0060

1

Keyboard controller byte, reset IRQ

0061

1

System port B

0064

1

Keyboard controller, CMD/ATAT byte

0070, bit 7

1 bit

Enable NMI

0070, bits 6:0

6 bits

Real-time clock, address

0071

1

Real-time clock, data

© Copyright IBM Corp. 2001

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