The following table lists I/O addresses used by legacy ISA devices and therefore considered fixed.
Legacy ISA System I/O
I/O Address | Default system function |
0000 � 000F | Slave DMA |
0010 � 0018 | System |
0001F | System |
0020 � 0021 | Master 8259 |
0040 � 0043, 0048 � 004B | PIT #1, PIT #2 |
0050 � 0052 | System |
0060 | Keyboard / mouse controller |
0061 | System control port B |
0064 | Keyboard / mouse status |
0070 � 0071 | NMI Enable / real-time clock |
0081 � 008B | DMA page registers |
0090 � 0091 | System |
0092 | System control port A |
0093 � 009F | System |
00A0 � 00A1 | Slave interrupt controller |
00C0 � 00DE | Master DMA controller |
00F0 � 00F1 | Coprocessor busy clear/reset |
0170 � 0177 | Secondary IDE controller |
01F0 � 01F7 | Primary IDE controller |
0201 | Joystick interface |
0220 � 022F | Sound Blaster |
0278 � 027A | LPT 2 (XT parallel port 3) |
02E8 � 02EF | Alternate COM (4) |
02F8 � 02FF | COM 2 |
0330 � 0331 | MPU-401 |
0376 | IDE Controller |
0378 � 037A | LPT 1 (XT parallel port 2) |
0388 � 038B | FM synthesis |
03B0 � 03BB | MDA, EGA / VGA |
03BC � 03BE | LPT 3 (XT parallel port 1) |
03C0 � 03DF | EGA / VGA |
03E0 � 03E7 | PCIC PCMCIA controllers |
03E8 � 03EF | Alternate COM (3) |
03F0 � 03F7 | FDC |
03F8 � 03FF | COM 1 |
0534 � 0537 | Windows Sound System-compatible |
0CF8 � 0CFB | PCI ports |