Intel Desktop Board D850MD/D850MV Technical Product Specification
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The ICH2 has eight programmable interrupt request (PIRQ) input signals. All PCI interrupt
sources either onboard or from a PCI add-in card connect to one of these PIRQ signals. Some PCI
interrupt sources are electrically tied together on the D850MD and D850MV boards and therefore
share the same interrupt. Table 18 shows an example of how the PIRQ signals are routed on the
D850MD and D850MV boards.
For example, using Table 18 as a reference, assume an add-in card using INTB is plugged into PCI
bus connector 3. In PCI bus connector 3, INTB is connected to PIRQB, which is already
connected to the SMBus controller, ICH2 audio/modem, and the AGP connector. The add-in card
in PCI bus connector 3 now shares interrupts with these onboard interrupt sources.
Table 18. PCI Interrupt Routing Map
ICH2 PIRQ Signal Name
PCI Interrupt Source
PIRQF PIRQG PIRQH PIRQB Other
AGP connector INTB INTA to PIRQA
ICH2 USB controller INTD to PIRQD
SMBus controller INTB
ICH2 USB controller INTC to PIRQC
ICH2 Audio / Modem INTB
ICH2 LAN INTA to PIRQE
OHCI controller 1
(Note 1)
INTD to PIRQA
OHCI controller 2
(Note 1)
INTC to PIRQB
EHCI controller
(Note 1)
INTH to PIRQC
PCI Bus Connector 1 INTA INTB INTC INTD
PCI Bus Connector 2 INTD INTA INTB INTC
PCI Bus Connector 3 INTC INTD INTA INTB
PCI Bus Connector 4
(Note 2)
INTB INTC INTD INTA
PCI Bus Connector 5
(Note 2)
INTA INTB INTC INTD
Notes:
1. USB 2.0 option only
2. D850MV board only
✏
NOTE
The ICH2 can connect each PIRQ line internally to one of the IRQ signals (3, 4, 5, 6, 7, 9, 10, 11,
12, 14, and 15). Typically, a device that does not share a PIRQ line will have a unique interrupt.
However, in certain interrupt-constrained situations, it is possible for two or more of the PIRQ
lines to be connected to the same IRQ signal.
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