Assigning Irqs For Expansion Cards; Standard Interrupt Assignments; Interrupt Request Table For This Motherboard - Fujitsu D1271 Technical Manual

3. HARDWARE SETUP

3.7.2 Assigning IRQs for Expansion Cards

Some expansion cards need an IRQ to operate. Generally, an IRQ must be exclusively
assigned to one use. In a standard design, there are 16 IRQs available but most of
them are already in use, leaving 6 IRQs free for expansion cards.
IMPORTANT: If using PCI cards on shared slots, make sure that the drivers support
"Share IRQ" or that the cards do not need IRQ assignments. Conflicts arise between
the two PCI groups that will make the system unstable or cards inoperable.
The following table lists the default IRQ assignments for standard PC devices. Use
this table when configuring your system and for resolving IRQ conflicts.

Standard Interrupt Assignments

IRQ Priority
0
1
2 N/A
3*
4*
5*
6
7*
8
9*
10*
11*
12*
13
14*
15*
*These IRQs are usually available for ISA or PCI devices.

Interrupt Request Table for this Motherboard

PCI slot 1
PCI slot 2
PCI slot 3
PCI slot 4
Onboard AGP
Onboard LAN1
Onboard LAN2
Onboard SCSI CHA (optional)
Onboard SCSI CHB (optional)
Onboard USB Controller
28
Standard Function
1 System Timer
2 Keyboard Controller
Programmable Interrupt
11 Communications Port (COM2)
12 Communications Port (COM1)
13 Sound Card (sometimes LPT2)
14 Floppy Disk Controller
15 Printer Port (LPT1)
3 System CMOS/Real Time Clock
4 ACPI Mode when used
5 IRQ Holder for PCI Steering
6 IRQ Holder for PCI Steering
7 PS/2 Compatible Mouse Port
8 Numeric Data Processor
9 Primary IDE Channel
10 Secondary IDE Channel
INT-A
shared
—
—
—
shared
—
—
—
shared
—
D1271 / D1291 CUV-LSV / CUV-LV User's Manual
INT-B INT-C
— —
shared —
— shared
— —
— —
shared —
— shared
— —
— —
— —
INT-D
—
—
—
shared
—
—
—
shared
—
shared