1st MB Memory Address Map

 

Memory address

 

Description

 

 

 

00000-9FFFF

 

System memory

 

 

 

A0000-BFFFF

 

 

VGA buffer

 

 

 

F0000-FFFFF

 

System BIOS

 

 

 

1000000-

 

Extend BIOS

 

 

IRQ Mapping Table

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

IRQ0

 

System Timer

 

IRQ8

 

RTC clock

 

IRQ1

 

Keyboard

 

IRQ9

 

USB2.0

 

IRQ2

 

Available

 

IRQ10

 

LAN

 

IRQ3

 

COM2

 

IRQ11

 

AUDIO/SMBus Cntrlr

 

IRQ4

 

COM1

 

IRQ12

 

PS/2 mouse

 

IRQ5

 

Available

 

IRQ13

 

FPU

 

IRQ6

 

FDC

 

IRQ14

 

Primary IDE

 

IRQ7

 

Available

 

IRQ15

 

Secondary IDE

 

DMA Channel Assignments

 

 

 

 

 

 

 

 

 

 

 

 

 

Channel

 

Function

 

 

 

 

 

0

 

 

Available

 

 

 

 

 

 

 

1

 

 

Available

 

 

 

 

 

 

 

2

 

 

Floppy disk (8-bit transfer )

 

 

3

 

 

Available

 

 

 

 

 

 

 

4

 

 

Cascade for DMA controller 1

 

 

5

 

 

Available

 

 

 

 

 

 

 

6

 

 

Available

 

 

 

 

 

 

 

7

 

 

Available

 

 

 

 

 

 

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IBM SAGP-845EV 1st MB Memory Address Map Memory address Description, IRQ Mapping Table, DMA Channel Assignments Function