5HP BIOS BIOS Addresses

HP I/O Port Map (I/O Addresses Used by the System1)

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).

 

Default Values for

Function

 

I/O Address Ports

 

 

 

 

 

0000

- 0CF7

DMA controller 1

 

 

 

0020

- 0021

Master interrupt controller (8259)

 

 

002E - 002F

Super I/O

 

 

 

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

 

 

 

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

Free (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

Free (IDE secondary channel, secondary floppy disk drive)

 

 

 

0378

- 037F

LPT1

 

 

03B0 - 03DF

VGA

 

 

03E8 - 03EF

COM3

 

 

03F0 - 03F5

Floppy disk drive controller

 

 

 

03F6

 

IDE primary channel

 

 

 

03F7

 

Floppy disk drive controller

 

 

 

1.If configured.

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