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HP Vectra VL 5/xxx Series 5 User Manual

Page 80

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80

4 Summary of the HP/Phoenix BIOS

BIOS Addresses

HP I/O Port Map (I/O Addresses Used by the System

1

)

Peripheral devices, accessory devices and system controllers are accessed
via the system I/O space, which is not located in system memory space. The
64 KB of addressable I/O space comprises 8-bit and 16-bit registers (called
I/O ports) located in the various system components. When installing an
accessory board, ensure that the I/O address space selected is in the free
area of the space reserved for accessory boards (100h to 3FFh).

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

1.

If configured (legacy resources only).

I/O Address Ports

Function

0000h - 000Fh

DMA controller 1

0020h - 0021h

Interrupt controller 1

0040h - 0043h

Interval timer 1

0060h, 0064h

Keyboard controller

0061h

System speaker, or NMI status and control

0070h

NMI mask register, RTC and CMOS address

0071h

RTC and CMOS data

0081h - 0083h, 008Fh

DMA low page register

0092h

Alternate reset and A20 Function

00A0h - 00A1h

Interrupt controller 2

00C0h - 00DFh

DMA controller 2

00EAh - 00EBh

Internal port

00F0h - 00FFh

Co-processor error

0102h

Graphics controller (Matrox MGA)

0170h - 0177h

IDE hard disk drive controller secondary channel

01F0h - 01F7h

IDE hard disk drive controller primary channel

0200h - 0207h

Joystick port (Soundblaster)