2-20
MS-9136 SSI Server Board
PCI Interrupt Request Routing
The IRQ, acronym of interrupt request line and pronounced I-R-Q, are hard-
ware lines over which devices can send interrupt signals to the microprocessor. The
PCI IRQ pins are typically connected to the PCI bus INT A# ~ INT D# pins as follows:
PCI33-32 Routing (From Hance Rapids)
PCI DEVICE
IDSEL
INT A
INT B
INT C
INT D
REQ
GNT
PCI Slot1
AD17
PIRQB#
PIRQC#
PIRQD#
PIRQA#
REQ0#
GNT0#
PCI66-32 Routing (From Hance Rapids)
PCI DEVICE
IDSEL
INT A
INT B
INT C
INT D
REQ
GNT
ATI VGA
AD17
PXIRQ0#
NA
NA
NA
PXREQ0#
PXGNT0#
GIGA LAN0
AD18
PXIRQ1#
NA
NA
NA
PXREQ1#
PXGNT1#
GIGA LAN1
AD19
PXIRQ2#
NA
NA
NA
PXREQ2#
PXGNT2#
PCIX-64 Routing (From PXH Channel A, 100MHz)
PCI DEVICE
IDSEL
INT A
INT B
INT C
INT D
REQ
GNT
PCI_2
AD18
PAIRQ_4#
PAIRQ_5#
SCSI_IRQA
SCSI_IRQB
PAREQ_1#
PAGNT_1#
PCI_3
AD17
PAIRQ_0#
PAIRQ_1#
PAIRQ_2#
PAIRQ_3#
PAREQ_0#
PAGNT_0#
SCSI_IRQA
PAIRQ_6#
SCSI_IRQB
PAIRQ_7#
AIC 7902
AD19
SCSI_IRQA
SCSI_IRQB
NA
NA
PAREQ_2#
PAGNT_2#
PCIX-64 Routing (From PXH Channel B, 266MHz)
PCI DEVICE
IDSEL
INT A
INT B
INT C
INT D
REQ
GNT
PCI_6
AD17
PBIRQ_0#
PBIRQ_1#
PBIRQ_2#
PBIRQ_3#
PBREQ_0#
PBGNT_0#
PCI Express Routing (From MCH)
PCI DEVICE
IDSEL
INT A
INT B
INT C
INT D
REQ
GNT
PCI_4
Group C x8
PCI_5
Group B x8
PXH
Group A x8
