Address Range (Hex) Size Description
------------------------------------------------------------------------
00000000-0007FFFF 512 KB DOS applications
640 KB Memory gap
768 KB Video buffer
1 MB Expansion and BIOS region
15 MB Cacheable
16 MB Optional memory space gap
512 MB Always cacheable
FEC00000-FEC01000 4 KB I/O APIC default
FEE00000-FE010000 4 KB APIC default
FFF80000-FFFDF000 384 KB Extended BIOS
FFFE0000-FFFFFFFF 128 KB BIOS memory shadowed
Input/Output Address Map Type 6589
The following list show the system board I/O address maps. Any addresses that are not shown are reserved.
I/O Address Map
Address (Hex) Device
------------------------------------------------------------------------
0000-000F DMA 1
0020-003F Interrupt controller 1
0040-0043 Timer 1
0048-004B Timer 2
0060 Keyboard controller data byte
0061 NMI, speaker control
0064 Keyboard controller command/status byte
0070, bit 7 Enable NMI
0070, bit 6, 0 Real-time clock, address
0071 Real-time clock, data
0078 Reserved (system board configuration)
007C Reserved (system board configuration)
0080-008F DMA page register
00A0-00A1 Interrupt controller 2
00C0-00DE DMA 2
00F0 Reset numeric error
0170-0177 Secondary IDE channel
01F0-01F7 Primary IDE channel
0278-027B Parallel port 2
02F8-02FF Onboard serial port 2
0376 Secondary IDE channel command port
0377 Secondary IDE channel status port
0378-037F Parallel port 1
03BC-03BF Parallel port x
03E8-03EF Serial port 3
03F0-03F5 Diskette channel 1
03F6 Primary IDE channel command port
03F7 (Write) Diskette channel 1 command
03F7, bit 7 Diskette change channel 1
03F7, bit 6, 0 Primary IDE channel status port
03F8-03FF Onboard serial port 1
LPT + 400h ECP port, LPT + 400h
0CF8-0CFB PCI configuration address register
0CFC-0CFF PCI configuration data register
FF00-FF07 IDE bus master register
DMA I/O Address Map Type 6589
DMA I/O Addresses for Memory Addresses, Word Counts and Command/Staus Registers
Address Description Bits Byte
(Hex) Pointer
------------------------------------------------------------------------
0000 Channel 0 Memory Address register 00-15 yes
0001 Channel 0 Transfer Count register 00-15 yes
0002 Channel 1 Memory Address register 00-15 yes
0003 Channel 1 Transfer Count register 00-15 yes
0004 Channel 2 Memory Address register 00-15 yes
0005 Channel 2 Transfer Count register 00-15 yes
0006 Channel 3 Memory Address register 00-15 yes
0007 Channel 3 Transfer Count register 00-15 yes
0008 Channels 0-3 Read Status/Write Command register 00-07
0009 Channels 0-3 Write Request register 00-02
000A Channels 0-3 Write Single Mask register bits 00-02
000B Channels 0-3 Mode register (write) 00-07
000C Channels 0-3 Clear byte pointer (write) N/A
000D Channels 0-3 Master clear (write)/temp (read) 00-07
000E Channels 0-3 Clear Mask register (write) 00-03
000F Channels 0-3 Write All Mask register bits 00-03
0081 Channel 2 Page Table Address register * 00-07
0082 Channel 3 Page Table Address register * 00-07
0083 Channel 1 Page Table Address register * 00-07
0087 Channel 0 Page Table Address register * 00-07
0089 Channel 6 Page Table Address register * 00-07
008A Channel 7 Page Table Address register * 00-07
008B Channel 5 Page Table Address register * 00-07
008F Channel 4 Page Table Address Refresh/reg. 00-07
00C0 Channel 4 Memory Address register 00-15 yes
00C2 Channel 4 Transfer Count register 00-15 yes
00C4 Channel 5 Memory Address register 00-15 yes
00C6 Channel 5 Transfer Count register 00-15 yes
00C8 Channel 6 Memory Address register 00-15 yes
00CA Channel 6 Transfer Count register 00-15 yes
00CC Channel 7 Memory Address register 00-15 yes
00CE Channel 7 Transfer Count register 00-15 yes
00D0 Channels 4-7 Read Status/Write Command register 00-07
00D2 Channels 4-7 Write Request register 00-02
00D4 Channels 4-7 Write Single Mask register bit 00-02
00D6 Channels 4-7 Mode register (write) 00-07
00D8 Channels 4-7 Clear byte pointer (write) N/A
00DA Channels 4-7 Master clear (write)/temp (read) 00-07
00DC Channels 4-7 Clear Mask register (write) 00-03
00DE Channels 4-7 Write All Mask register bits 00-03
00DF Channels 5-7 8-or-16 bit mode select 00-07
* Upper byte of Memory Address register
Please see the LEGAL - Trademark notice.
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for any BUG on this page found - Thank you.