5 HP BIOS

BIOS Addresses

 

Default Values for

Function

 

I/O Address Ports

 

 

 

 

 

0388

- 038B

 

 

 

03B0 - 03DF

VGA

 

 

03E8 - 03EF

 

 

 

 

03F0

- 03F5

 

 

 

 

03F6

 

IDE primary channel

 

 

 

03F7

 

Flexible disk drive controller

 

 

 

03F8

- 03FF

COM1

 

 

04D0 - 04D1

System board resources under Windows 95

 

 

 

0678

- 067B

 

 

 

 

0778

- 077B

LPT1 ECP

 

 

0CF8 - 0CFF

PCI configuration space

 

 

 

8000

-

 

 

 

 

8400

-

 

 

 

 

8800

-

 

 

 

 

DMA Channel Controllers

Only “I/O-to-memory” and “memory-to-I/O” transfers are allowed. “I/O-to-I/O” and “memory-to-memory” transfers are disallowed by the hardware configuration. The system controller supports seven DMA channels, each with a page register used to extend the addressing range of the channel to 16 MB. The following table summarizes how the DMA channels are allocated.

 

DMA controller

 

 

 

Channel

 

Function

 

 

 

DMA 0

 

Free

DMA 1

 

Free

DMA 2

 

Flexible disk drive controller

DMA 3

 

LPT ECP

DMA 4

 

DMA controller

DMA 5

 

Free

DMA 6

 

Free

DMA 7

 

Free

 

 

 

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