Legacy ISA I/O Address Assignments

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	Programmable interrupt timer (PIT) #1, PIT #2
0050–0052	System
0060	Keyboard/mouse controller
0061	System control port B
0064	Keyboard/mouse status
0070–0071	Nonmaskable Interrupt (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	Frequency modulation (FM) synthesis
03B0–03BB	MDA, EGA/video graphics array (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	Peripheral Component Interconnect (PCI) ports