Chapter 3 |
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Table |
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| IRQ# | Available | Typical Interrupt Source | Connected to Pin |
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| 0 | No | Counter 0 | NA |
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| 1 | No | Keyboard | NA |
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| 2 | No | Cascade Interrupt from Slave PIC | NA |
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| 3 | Note 1 | Serial Port 2 (COM2) / Generic | IRQ3 via SERIRQ |
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| 4 | Note 1 | Serial Port 1 (COM1) / Generic | IRQ4 via SERIRQ |
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| 5 | Note 2 | Parallel Port 2 (LPT2) / Generic | IRQ5 via SERIRQ |
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| 6 | Note 1 | Floppy Drive Controller / Generic | IRQ6 via SERIRQ |
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| 7 | Note 1 | Parallel Port 1 (LPT1) / Generic | IRQ7 via SERIRQ |
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| 8 | No | NA |
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| 9 | Note 4 | SCI / Generic | IRQ9 via SERIRQ |
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| 10 | Note 2, 1 | Serial Port 3 (COM3) / Generic | IRQ10 via SERIRQ |
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| 11 | Note 2, 1 | Serial Port 4 (COM4) / Generic | IRQ11 via SERIRQ |
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| 12 | Note 1 | PS/2 Mouse / Generic | IRQ12 via SERIRQ |
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| 13 | No | Math processor | NA |
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| 14 | Note 1, 3 | IDE Controller 0 (IDE0) / Generic | IRQ14 |
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| 15 | Note 1, 3 | IDE Controller 1 (IDE1) / Generic | IRQ15 |
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Notes: In PIC mode, the PCI bus interrupt lines can be routed to any free IRQ.
1.Default, but can be changed to another interrupt. If disabled in BIOS Setup, the interrupt can be used for another purpose.
2.Function described is available if the baseboard is equipped with the Super I/O controller Winbond (W83627HG). This I/O controller is supported by the XTX 820 Embedded BIOS.
3.If the ATA/IDE configuration is set to enhanced mode in BIOS setup (serial ATA and parallel ATA native mode operation), IRQ14 and 15 are free for PCI/LPC bus.
4.In ACPI mode, IRQ9 is used for the SCI (System Control Interrupt). The SCI can be shared with a PCI interrupt line.
Memory Map
The following table provides the common PC/AT memory allocations. Memory below 000500h is used by the BIOS.
Table
Address Range | Address Range |
(decimal) | (hex) |
NA | |
NA | |
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1024 k to (TOM- 8MB | 100000 - N.A |
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869 k - 1024 k | E0000 - FFFFF |
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800 k - 869 k | CC000 - DFFFF |
640 k - 800 k | A0000 - CBFFF |
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Size
192 kB
1 or 8 MB
NA
128kB
96kB
160kB
Description
ACPI reclaim, MPS and NVS area **
VGA frame buffer *
Extended memory
Runtime BIOS
Upper memory
Video memory and Video BIOS
XTX 820 | Reference Manual | 17 |