Reviewing System Features 3-5
Interrupt Controller
The interrupt controller operates as an interrupt manager
for the entire system environment. The controller accepts
requests from peripherals, issues interrupt requests to the
processor, resolves interrupt priorities, and provides vectors
for the processor to determine which interrupt routine to
execute. The interrupt controller has priority assignment
modes that can be reconfigured at any time during system
operations.
The interrupt levels are described in the following table.
Interrupt-level assignments 0 through 15 are in order of
decreasing priority. See “The Setup Utility” in Chapter 2
for information on changing the interrupts using the Setup
utility.
Interrupt Level Assignments
INTERRUPT PRIORITY
INTERRUPT DEVICE
IRQ00
Counter/Timer
IRQ01
Keyboard
IRQ02
Cascade (INT output from slave)
IRQ03
COM2 and COM4
IRQ04
COM1 and COM3
IRQ05
Audio (if present)
IRQ06
Diskette Drive Controller
IRQ07
Parallel Port 1
IRQ08
Real-time clock
IRQ09
S3 Video and USB
IRQ10
Available
IRQ11
Available
IRQ12
PS/2 mouse