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MS-6580 ATX Mainboard
PCI Interrupt Request Routing
The IRQ, abbreviation of interrupt request line and pronounced I-R-Q,
are hardware lines over which devices can send interrupt signals to the
microprocessor. The “AGP/PCI/USB/LAN” IRQ pins are typically connected
to the PCI bus INT A# ~ INT H# pins as follows:
Order 1 Order 2 Order 3 Order 4
AGP
INT A#
INT B#
PCI Slot 1
INT A#
INT B#
INT C# INT D#
PCI Slot 2
INT B#
INT C# INT D# INT A#
PCI Slot 3
INT C# INT D# INT A#
INT B#
PCI Slot 4
INT D# INT A#
INT B#
INT C#
PCI Slot 5
INT B#
INT C# INT D# INT A#
PCI Slot 6
INT A#
INT B#
INT C# INT D#
USB1.1 Controller 1 INT A#
USB1.1 Controller 2 INT D#
USB1.1 Controller 3 INT C#
USB2.0 Controller
INT H#
LAN Controller
INT E#
AGP & PCI Slot 1 & PCI Slot 6 & USB1.1 Controller 1 shared INT A#.
PCI Slot 2 & PCI Slot 5 shared INT B#.
PCI Slot 3 & USB1.1 Controller 3 shared INT C#.
PCI Slot 4 & USB1.1 Controller 2 shared INT D#.
