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Dma channel controllers – HP XU800 User Manual

Page 104

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104

5 HP BIOS

BIOS Addresses

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.

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 -

Default Values for

I/O Address Ports

Function

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