APPENDIX A: Resource Allocation

A.1. System Interrupts

Default IRQ

PIR

Function

Alternative Mappings

Device

IRQ0

  Timer N/A

South Bridge

IRQ1

  Keyboard N/A

South Bridge

IRQ2

  Internal 8259 Cascade N/A

South Bridge

IRQ3

X

Modem Model Specific

Modem

IRQ4

X

COM1 Serial Port 3, Disabled

Super I/O

IRQ5

X

Audio 7, 9, 10, 11, Disabled

Audio Controller

IRQ6

X

Floppy Disk Controller Disabled

Super I/O

IRQ7

X

LPT1 Parallel Port 3, 4, 5, 9, 10, Disabled

Super I/O

IRQ8

  Real Time Clock N/A

South Bridge

IRQ9

X

USB, NIC PIR

USB Controller

IRQ10

X

     

IRQ11

X

     

IRQ12

X

PS/2 Mouse Disabled

South Bridge

IRQ13

  Numeric Coprocessor Disabled

South Bridge

IRQ14

X

Primary IDE PIR, Disabled

IDE Controller

IRQ15

X

Secondary IDE PIR, Disabled

IDE Controller

A.2. System DMA Channels

Default DMA

Function

Alternative Mapping

Device

DMA0

Audio Record

1, 3, Disabled

Audio Controller

DMA1

Audio Playback

0, 3, Disabled

Audio Controller

DMA2

Floppy Controller

N/A

Super I/O

DMA3

ECP Printer Port

0, 1, 2, Disabled

Super I/O

DMA4

Internal Cascade

N/A

South Bridge

DMA5

Available

 

South Bridge

DMA6

Available

 

South Bridge

DMA7

Available

 

South Bridge

 

A.3. System I/O Map

Low I/O

Address

High I/O

Address

Function

Alternative

Mappings

Device

0000

000F

DMA Controller #1  

South Bridge

0010

001F

DMA Controller Aliases  

South Bridge

0020

  Interrupt Controller #1 Control Register  

South Bridge

0021

  Interrupt Controller #1 Mask Register  

South Bridge

0022

003D

Interrupt Controller Aliases  

South Bridge

0040

0043

Counter/Timer  

South Bridge

0044

004F

   

Not used

0050

0053

Counter/Timer Aliases  

South Bridge

0053

005F

   

Not used

0060

  Keyboard Controller Data Register  

South Bridge

0061

  Port B: SERR/IOCHK NMI, Speaker, Refresh  

South Bridge

0062

0063

   

Not used

0064

  Keyboard Controller Command/Status Register  

South Bridge

0065

006F

   

Not Used

0070

  NMI Mask Register (Bit 7)  

South Bridge

0070

  RTC/Configuration Memory Index Port (Bit 6:0)  

South Bridge

0071

  RTC/Configuration Memory Data Port  

South Bridge

0072

  RTC Extended Index  

South Bridge

0073

  RTC Extended Data  

South Bridge

0074

007F

   

Not Used

0080

008F

DMA Page Registers  

South Bridge

0090

0091

Alias of DMA page registers if SOUTH BRIDGE.4C.7=0  

South Bridge

Not Used

0092

  Port 92 (fast reset and A20 gate)  

South Bridge

0093

009F

Alias of DMA page registers if SOUTH BRIDGE.4C.7=0  

South Bridge

Not used

00A0

  Interrupt Controller #2 Control Register  

South Bridge

00A1

  Interrupt Controller #2 Mask Register  

South Bridge

00A2

00B1

   

Not Used

00B2

  APM Control  

South Bridge

00B3

  APM Status  

South Bridge

00B4

00BF

   

Not Used

00C0

00DF

DMA Controller #2  

South Bridge

00E0

  ESS Index Register  

Audio

00E1

  ESS Data Register  

Audio

00E2

00E3

DDC2 Registers    

00E4

00E9

   

Not used

00EA

  Ultra I/O Index Register  

Super I/O

00EB

  Ultra I/O Data Register  

Super I/O

00EC

00EF

Modem configuration  

Modem

00F0

00F1

Coprocessor Busy Clear/Reset  

South Bridge

00F2

00F8

   

Not Used

00F9

  Lock Configuration Register (Dummy Write)  

Audio, Modem, Super I/O

00FA

     

Not used

00FB

  Unlock Configuration Register (Dummy Write)  

Audio, Modem, Super I/O

00FC

  TV/MPEG Configuration Register to remap base I/O address and interrupt resource    

00FD

00FF

   

Not Used

0100

0101

   

Not Used

0102

  Video: POS. 102 register  

Video

0103

012F

   

Not Used

0130

0131

BGL Index/Data for second line modem

See 260 for controllerless modems

 

Modem

0132

016F

   

Not Used

0170

0177

Secondary IDE Controller  

South Bridge

0178

01EF

   

Not Used

01F0

01F7

Primary IDE Controller  

South Bridge

01F8

0200

   

Not Used

0201

  Joystick Port

200,202,203

Audio

0202

021F

   

Not Used

0220

022F

Audio Controller

0230-023F,

0240-024F,

0250-025F

Audio

0230

025F

   

Not Used

0260

0263

Reserved-Modem use during POST    

0264

0277

   

Not Used

0278

027F

Reserved-Parallel Port

0378

Super I/O

0280

02E7

   

Not Used

02E8

02EF

Reserved-Serial Port (COM4)

03F8

Super I/O

02F0

02F7

   

Not Used

02F8

02FF

FAX/Modem (COM2)

02E8-02EF,

03E8-03EF,

03F8-03FF

Modem

0330

0331

MPU-401

0300-0301

0310-0321

0320-0321

disabled

Audio

0332

036F

   

Not Used

0370

0377

Reserved-Floppy Drive Controller 2  

Super I/O

0378

037F

Parallel Port

0278-27F

03BC-3BF

Super I/O

0380

0387

   

Not Used

0388

038B

Audio FM Synthesizer  

Audio

038C

03B3

   

Not Used

03B4

03B5

Video: Monochrome  

Video

03B6

03B9

   

Not Used

03BA

  Video: Monochrome  

Video

03BB

     

Not Used

03BC

03BF

Reserved-Parallel Port  

Super I/O

03C0

03CF

Video: VGA Registers  

Video

03D0

03D3

   

Not Used

03D4

03D5

Video: Color  

Video

03D6

03D9

   

Not Used

03DA

  Video: Color  

Video

03DB

03E7

   

Not Used

03E8

03EF

Reserved-Serial Port (COM3)  

Super I/O

03F0

03F7

Floppy Disk Controller (Primary)  

Super I/O

03F6

03F7

IDE Interface (Fixed Disk and CDROM)  

South Bridge

03F8

03FF

Serial Port (COM1)  

Super I/O

0400

04EF

   

Not Used

04D0

  Interrupt Controller #1 Edge/Level Control  

South Bridge

04D1

  Interrupt Controller #2 Edge/Level Control  

South Bridge

04D2

0677

   

Not Used

0678

067A

Parallel Port ECP Mode  

Super I/O

0778

077A

Parallel Port ECP Mode  

Super I/O

0CF8

  PCI Configuration Index (32-bit I/O only)  

North Bridge

0CF9

  Reset Control  

South Bridge

0CFC

  PCI Configuration Data  

North Bridge

46E8

  Video: Adapter Sleep  

Video

Table A.3. System I/O Map

 

A.4. System Memory Map

Size Low Address High Address System Function
640 KB 00000000 0009FFFF Base Memory
128 KB 000A0000 000BFFFF Video RAM
48 KB 000C0000 000CBFFF Video ROM
16 KB 000CC000 000CFFFF Unused
48 KB 000D0000 000DBFFF Unused
16 KB 000DC000 000DFFFF Used
64 KB 000E0000 000EBFFF Used
64 KB 000F0000 000FFFFF System BIOS ROM shadow image
15 MB 00100000 00FFFFFF Standard Extended Memory
64 MB 01000000 04FFFFFF Rest of Extended Memory
60 MB 05000000 07FFFFFF Unused
512 KB 08000000 0807FFFF Standard Direct Video Memory
512 KB 08080000 080FFFFF Optional Direct Video Memory
1919 MB 08100000 7FFFFFFF Unused
16 MB 80000000 80FFFFFF Memory mapped I/O devices
~2000 MB 81000000 FDFDFFFF Unused/System ROM aliases
128 KB FDFE0000 FDFFFFFF System ROM (alias)
~32 MB FE000000 FFFDFFFF Unused
128 KB FFFE0000 FFFFFFFF System BIOS ROM

Table A.4. System Memory Map