I/O Address USE 0000-000f Slave DMA controller (8237 chip) 0010-001F System 0020-0021 First Interrupt controller (8259 chip) 0030-0031 Second interrupt controller 0040-0043 Programable Interval Timer 1 (8254 chip) 0048-004B Programable Interval Timer 2 0050-006F System devices 0070-0071 NMI Enable / Real Time Clock 0080-008B DMA Page registers 0090-009F System devices 00A0-00A1 Slave interrupt controller 00C0-00DE Master DMA controller 00F0-00FF System devices 0100-0167 System devices 0168-016F IDE Interface - Quaternary channel 0170-0177 IDE interface - Secondary channel 01E8-01EF IDE Interface - Tertiary channel 01F0-01F7 IDE interface - Primary channel 0200-0207 Games Port (joystick port) 0220-022F Usually used by sound cards, also used by NOVEL NETWARE KEY CARD 0270-0273 Plug and Play hardware 0278-027A Parallel Port * 0280-028F Sometimes used for LCD Display I/O 02B0-02DF Alternate VGA Video Display Adaptor assignment (secondary address) 02E0-02E7 GPIB 0, data aquisition card 0 (02E1 to 02E3 only) 02E8-02EF Serial Port - COM 4 02F8-02FF Serial Port - COM 2 0300-031F Often used as a default for Network Interface cards (was prototype card) 0320-023F ST506 and ESDI Hard Disk Drive Interface (mostly used in PX/XT and early PC/AT) 0330-0331 MPU-401 (midi) interface, on Sound Cards 0360-036F Sometimes used for Network Interface cards 0376-0377 Another address used by the Secondary IDE Controller (see 0170-0177) 0378-037A Parallel Port * 0388-038B FM (sound) synthesis port on sound cards 03B0-03BB MDA, EGA and VGA Video Display Adaptor (only 03B0 to 03BB used) 03BC-03BF Parallel Port (originally only fitted to IBM mono display adaptors) * 03C0-03DF EGA / VGA Video Display Adaptor, (Primary address) 03E0-03E7 PCIC PCMCIA Port Controller 03E8-03EF Serial Port - COM 3 03F0-03F6 Floppy Disk Drive Interface 03F7-03f7 Another address used by the Primary IDE Controller (see 01F0-01F7) 03F8-03FF Serial Port - COM 1 0533-0537 Windows sound system (used by many sound cards) These next assignments are recent additions, and are used by some modern chip-sets used in System Boards. 0678-067F Used by the Extended Parallel Port at 0278 (more about EPP soon) 0778-077F Used by the Extended Parallel Port at 0378 (more about EPP soon) 07BC-07C5 Used by the Extended Parallel Port at 03BC (more about EPP soon) 0CF8-0CFB PCI data registers FF00-FF07 IDE Bus Mastering Registers FFA0-FFA7 Primary IDE Bus Mastering Registers FFA8-FFAF Secondary IDE Bus Mastering Registers
* The three Parallel Port assignments listed in this table are assigned as LPT1 to LPT3 in the following order : 3BC, 378, 278. Usually a PC has only one Parallel Port and the BIOS setup routines assignes the first Parallel Port hardware it finds in the above order, to LPT1. If a second Parallel Port is found it will be assigned LPT2, in the order above.
|Back to the PC and its I/O Ports||Back to the opening index||Book two index|
|The PCs Parallel ports||The PCs Serial (Comms) ports||The Games (Joystick) port|