
4 BIOS overview
BIOS addresses
Although the Setup program can be used to change some of the settings, the following address map is not completely BIOS dependent, but is determined partly by the operating system. Note that some of the I/O addresses are allocated dynamically.
| I/O Address Ports | Function |
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0000 | - 000F | DMA controller |
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Motherboard resources | ||
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0020 | - 0021, | Programmable Interupt Controller |
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0040 | - 0043 | System Timer |
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| |
0060, 0064 | PC/AT Enhanced Keyboard | |
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|
0061 |
| System Speaker |
|
|
|
0070 | - 0071 | RTC and CMOS data |
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|
|
0081 | - 0083, 008F, 0087, | DMA Controller |
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00F0 - 00FF | Numeric Data Processor | |
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0170 | - 0177 | Ultra ATA Controller, Secondary ATA Controller |
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| |
01F0 - 01F7 | Ultra ATA Controller, Primary ATA Controller | |
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|
|
0376 |
| Ultra ATA Controller, Secondary ATA Controller |
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|
|
0378 | - 037F, 0778 - 077F | LPT1 ECP |
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03F8 - 03FF | COM1 | |
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0CF8 - 0CFF | PCI bus | |
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Chipset Graphic Drivers | ||
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SMBus controller | ||
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PCI Bridge | ||
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NIC | ||
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03F6, FFA0 - FFA7, | Ultra ATA Controller, Primary ATA Controller | |
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USB Universal Host Controller | ||
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Audio | ||
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Primary ATA Controller | ||
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| |
Ultra ATA Controller | ||
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| |
Secondary ATA Controller | ||
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