Chapter 3 BIOS Setup
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NET-1821VD2N
IO Port Address
Only 16 IO address lines are designed for X86, from 0 ~ 0FFFFh; there is 64K for the
system I/O address space. In traditional ISA connector, only the foregoing 1024 (0000
~ 03FFh) are adopted while the ports above 0400h are adopted by PCI and EISA
connectors. Each peripheral will occupy portion of the space. The table below shows
parts of the I/O connectors used in X86 platform.
Address
Device Description
000h - 00Fh
DMA Controller #1
010h - 01Fh
Motherboard Resource
020h - 021h
Programmable Interrupt Controller #1
022h - 03Fh
Motherboard Resource
040h - 043h
System Timer
044h - 05Fh
Motherboard Resource
060h
Standard 101/102 Key or Microsoft Natural PS/2 Keyboard
061h System
speaker
062h – 063h
Motherboard Resource
064h
Standard 101/102 Key or Microsoft Natural PS/2 Keyboard
065h - 06Fh
Motherboard Resource
070h - 071h
Real Time Clock, NMI
072h – 07Fh
Motherboard Resource
080h Motherboard
Resource
081h - 083h
DMA Controller #2
084h - 086h
Motherboard Resource
087h
DMA Controller #3
088h Motherboard
Resource
089h - 08Bh
DMA Controller #4
