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HP Vectra VL400 User Manual

Page 47

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47

4 BIOS Overview

BIOS Addresses

Although the Setup program can be used to change some of the settings, the
following address map is not completely BIOS dependent, but is determined
partly by the operating system. Note that some of the I/O addresses are
allocated dynamically.

I/O Address Ports

Function

0000 - 000F

DMA controller 1

0020 - 0021

Master interrupt controller (8259)

002E - 002F

NS364 Configuration registers

0040 - 0043

Timer 1

0060, 0064

Keyboard controller (reset, slow A20)

0061

Port B (speaker, NMI status and control)

0070

Bit 7: NMI mask register

0070 - 0071

RTC and CMOS data

0080

Manufacturing port (POST card)

0081 - 0083, 008F

DMA low page register

0092

PS/2 reset and Fast A20

00A0 - 00A1

Slave interrupt controller

00C0 - 00DF

DMA controller 2

00F0 - 00FF

Co-processor error

0170 - 0177

IDE secondary channel

01F0 - 01F7

IDE primary channel

0278 - 027F

LPT 2

02E8 - 02EF

Serial port 4 (COM4)

02F8 - 02FF

Serial port 2 (COM2)

0372 - 0377

IDE secondary channel, secondary floppy disk drive

0378 - 037A

LPT1

03B0 - 03DF

VGA

03E8 - 03EF

COM3

03F0h- 03F5

Floppy disk drive controller

03F6

IDE primary channel

03F7

Floppy disk drive controller

03F8 - 03FF

COM1

04D0 - 04D1

Interrupt edge/level control

0678 - 067B

LPT2 ECP

0778 - 077B

LPT1 ECP

0CF8 - 0CFF

PCI configuration space