Abit AB-NV7-133R, User Manual

Page: 54 / 96

Chapter 3
NV7-133R
3-26
PCI Latency Timer:
The DEC (decimal) numbers from 0 to 255 are available, with the default setting at 32 . This item can let
you set the PCI latency clock delay time. Which means, you can set how many clocks you want it delay.
PIRQ_0 Use IRQ No. ~ PIRQ_3 Use IRQ No.:
Eleven options are available: Auto, 3, 4, 5, 7, 9, 10, 11, 12, 14, 15. Default setting is Auto. This item
allows the system to automatically specify the IRQ number for the device installed on PCI slots. This
means that the system can specify the fixed IRQ number for the device installed on the PCI slots (PCI slot
1 to PCI slot 6). This is a useful function for when you want to fix the IRQ for a specific device.
For example, if you want to move your hard disk to another computer and don’t want to re-install
Windows
®
NT or Windows
®
2000, you can simply specify the IRQ for the device installed on the new
computer to fit the original computer settings.
This feature is for the operating system that will record and fix the PCI configuration status if you want to
change it.
For the relations between the hardware layout of PIRQ (the signals from the VIA VT8233 chipset), INT#
(means PCI slot IRQ signals) and devices, please refer to the table below:
SIGNALS
PCI
Slot 1
PCI
Slot 2
PCI
Slot 3
PCI
Slot 4
PCI
Slot 5
PIRQ_0 Assignment INT A INT D INT C INT B INT A
PIRQ_1 Assignment
INT B INT A INT D INT C INT B
PIRQ_2 Assignment INT C INT B INT A INT D INT C
PIRQ_3 Assignment
INT D INT C INT B INT A INT D
!
USB 2.0 used PIRQ_0, PIRQ_1 and PIRQ_3.
Note
!
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.
!
PCI slot 3 shares IRQ signals with the HPT 372 IDE controller (supports Ultra DMA 133). The
driver for HPT 372 IDE controller supports IRQ sharing with other PCI devices. But if you install
a PCI card that doesn’t allow IRQ sharing with other devices into PCI slot 3, you may encounter
problems. Furthermore, if your Operating System doesn’t allow peripheral devices to share IRQ
signals with each other, such as Windows
®
NT for example, you can’t install a PCI card into PCI
slot 3.
!
HPT 372 IDE controller is designed to support high-speed and high performance mass storage
devices. Thus, we suggest that you don’t connect non-disk devices that use ATA/ATAPI
interfaces, such as a CD-ROM, to HPT 372 IDE connector (IDE3 & IDE4).