System I/O |
Low and High I/O Addresses (Hex) |
System Function (Shipping Configuration) |
0000 - 000F |
DMA Controller # 1 |
0010 - 001F |
DMA controller aliases |
0020 |
Interrupt Controller # 1
Control Register |
0021 |
Interrupt Controller #1
Mask Register |
0022 - 003D |
Interrupt Controller
Aliases |
040 - 0043 |
Counter/Timer |
0044 - 004F |
Unused |
0050-0053 |
Counter/Timer Aliases |
0053-005F |
Unused |
0060 |
Keyboard Controller Data
Register |
0061 |
Port B: SERR/IOCHK NMI,
Speaker, Refresh |
0062 - 0063 |
Unused |
0064 |
Keyboard Controller
Command/Status Register |
0065 - 006F |
Unused |
0070 |
NMI mask register (bit
7) |
0070 |
RTC/Configuration Memory
Index Port (bit 6:0) |
0071 |
RTC/Configuration Memory
Data Port |
0072 |
RTC Extended Index |
0073 |
RTC Extended Data |
0074-007F |
Unused |
0080 - 008F |
DMA Page Registers |
0090 - 0091 |
Unused (alias of DMA
page registers if PIIX4.4C.7=0) |
0092 |
Port 92 (fast reset and
A20 gate) |
0093 - 009F |
Unused (alias of DMA
page registers if PIIX4.4C.7=0) |
00A0 |
Interrupt Controller # 2
Control Register |
00A1 |
Interrupt Controller # 2
Mask Register |
00A2 - 00B1 |
Unused |
00B2 |
APM Control |
00B3 |
APM Status |
00B4-00BF |
Unused |
00C0 - 00DF |
DMA Controller # 2 |
00E0 |
ESS Index Register |
00E1 |
ESS Data Register |
00E2 - 00E3 |
DDC2 Registers |
00E4 - 00E5 |
Master I2C Interface |
00E6 |
TV/MPEG Configuration
Register |
00E7 - 00E9 |
Unused |
00EA |
Ultra I/O Index Register |
00EB |
Ultra I/O Data Register |
00EC- 00EF |
Modem Configuration |
00F0 - 00F1 |
Coprocessor Busy
Clear/Reset |
00F2 - 00F8 |
Unused |
00F9 |
Lock Configuration
Register (Dummy Write) |
00FA |
Unused |
00FB |
Unlock Configuration
Register (Dummy Write) |
00FC |
TV/MPEG Configuration
Register to remap base I/O address and interrupt resource |
00FD-00FF |
Unused |
0100 - 0101 |
Unused |
0102 |
Video: POS. 102 Register |
0103-012F |
Unused |
0130-0131 |
BGl Index/Data for
second line modem See 260 for controllerless modems. |
0132 - 016F |
Unused |
0170 - 0177 |
Secondary IDE Controller
(CD Drive) |
0178 - 01EF |
Unused |
01F0 - 01F7 |
Primary IDE Controller
(Hard Drive) |
01F8 - 0200 |
Unused |
0201 |
Joystick Port |
0202 - 021F |
Unused |
0220 - 022F |
Audio Controller |
0230 - 025F |
Unused |
0260 - 0263 |
Reserved - Modem use
during POST |
0264 - 0277 |
Unused |
0278 - 027F |
Reserved - Parallel Port
(LPT 2) |
0280 - 02E7 |
Unused |
02E8 - 02EF |
Reserved - Serial Port
(COM 4) |
02F0 - 02F7 |
Unused |
02F8 - 02FF |
Fax/Modem (COM 2) |
0330 - 0331 |
MPU-401 |
0332 - 036F |
Unused |
0370 - 0377 |
Reserved - Diskette
Drive Controller 2 |
0378 - 037F |
Parallel Port |
0380 - 0387 |
Unused |
0388 - 038B |
Audio FM Synthesizer |
038C - 03B3 |
Unused |
03B4 - 03B5 |
Video: Monochrome |
03B6 - 03B9 |
Unused |
03BA |
Video: Monochrome |
03BB |
Unused |
03BC -03BF |
Reserved - Parallel Port |
03C0 -03CF |
Video: VGA Registers |
03D0 - 03D3 |
Unused |
03D4 - 03D5 |
Video: Color |
03D6 - 03D9 |
Unused |
03DA |
Video: Color |
03DB - 03E7 |
Unused |
03E8 - 03EF |
Reserved - Serial Port
(COM 3) |
03F0 - 03F7 |
Diskette Controller
(Primary) |
03F6 - 03F7 |
IDE Interface (Fixed
disk and CD or DVD Drive) |
03F8 - 03FF |
Serial Port (COM 1) |
0400 - 04EF |
Unused |
04D0 |
Interrupt Controller #1
Edge/Level Control |
04D1 |
Interrupt Controller #2
Edge/Level Control |
04D2 - 0677 |
Unused |
0678 - 067A |
Parallel Port ECP Mode |
0778 - 077A |
Parallel Port ECP Mode |
0CF8 |
PCI Configuration Index
(32-bit I/O only) |
0CFC |
PCI Configuration Data |
46E8 |
Video:
Adapter Sleep |