MSI MS-6378 - PCI Interrupt Request Routing

Chapter 2
2-24
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 “PCI/USB/AC97/AN983B” IRQ pins are typically con-
nected to the PCI bus INT A# ~ INT D# pins as follows:
Order 1 Order 2 Order 3 Order 4
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#
USB-1 INT D# INT A# INT B# INT C#
USB-2 INT D# INT A# INT B# INT C#
AC97 INT C# INT D# INT A# INT B#
AN983B INT D#
PCI Slot 3 & AC97 shared.
USB & AN983B shared.
PCI Slot 1~3: Bus Master