Download Abit IS-10 Intel Pentium 4 System Board Socket 478 User`s manual

3-22
Chapter 3
Allocate IRQ To Video:
This item assigns an IRQ for the VGA card installed.
[Enabled]: Automatically assign an IRQ for the VGA card installed.
[Disabled]: The IRQ that was previously occupied by the VGA card will be available for new device.
Allocate IRQ To USB:
This item assigns an IRQ for the USB device connected.
[Enabled]: Automatically assign an IRQ for the USB device connected.
[Disabled]: The IRQ that was previously occupied by the USB device connected will be available for
new device.
PCI Latency Timer(CLK):
This item controls how long each PCI device can hold the bus before another takes over. When set to
higher values, every PCI device can conduct transactions for a longer time and thus improve the effective
PCI bandwidth. For better PCI performance, you should set the item to higher values.
PIRQ_0 Use IRQ No. ~ PIRQ_3 Use IRQ No.:
This item specifies the IRQ number manually or automatically for the devices installed on PCI slots.
For the relations between the hardware layout of PIRQ (the signals from the VIA VT8237 chipset), INT#
(means PCI slot IRQ signals) and devices, please refer to the table below:
Signals
PIRQ_0 Assignment
PIRQ_1 Assignment
PIRQ_2 Assignment
PIRQ_3 Assignment
PIRQ_4 Assignment
PIRQ_5 Assignment
PIRQ_6 Assignment
PIRQ_7 Assignment
LAN PCI-1
AGP
INT A INT A INT A
INT B
INT B
INT C
INT D
PCI-2
INT D
INT A
INT B
INT C
PCI-3
INT C
INT D
INT A
INT B
PCI-4
INT B
INT C
INT D
INT A
PCI-5 SATA
INT A
INT B INT A
INT C
INT D
NOTE:
•
PCI slot 1 shares IRQ signals with PCI slot 5, AGP slot, and LAN.
•
If you want to install two PCI cards into those PCI slots that share IRQ with one another at the same
time, you must make sure that your OS and PCI devices’ driver supports the IRQ sharing function.
VT7