Memory map
| Address Range (hex) | Amount | Function | |
0 to 07FFFFh | 640 KB | DOS region, base system memory | |
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0A0000h to 0BFFFFh | 128 KB | Video or SMM memory | |
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0C0000h and 0DFFFFh | 128 KB | Expansion card BIOS and buffer | |
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| area |
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0F0000h to 0FFFFFh | 128 KB | System BIOS | |
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0E0000h to 0EFFFFh | 64 | KB | Extended system BIOS |
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FC000000h to FFFFFFFFh | 64 | MB | PCI memory space |
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Interrupts
The following table suggests a logical interrupt mapping of interrupt sources. It reflects a typical configuration, but you can change these interrupts. Use the information to determine how to program each interrupt. The actual interrupt map is defined using configuration registers in the I/O controller. I/O Redirection Registers in the I/O APIC are provided for each interrupt signal. The signals define hardware interrupt signal characteristics for APIC messages sent to local APIC(s).
Important | If you disable either IDE controller to free the interrupt for |
| that controller, you must physically unplug the IDE cable |
| from the system board. Simply disabling the drive by |
| configuring the SSU option does not make the interrupt |
| available. |
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| Interrupt | I/O APIC | Description |
| Level |
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INTR | INT0 | Processor interrupt |
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NMI | N/A | NMI from PIC to processor |
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IRQ1 | INT1 | Keyboard interrupt |
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Cascade | INT2 | Interrupt signal from second 8259 |
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IRQ3 | INT3 | Serial port A or B interrupt from SIO device (you can configure either) |
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IRQ4 | INT4 | Serial port A or B interrupt from SIO device (you can configure either) |
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IRQ5 | INT5 | Parallel port II |
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System Specifications | 119 |