1-10 Technical Information
Table Section 1-5 SIMM Memory Upgrade Path
Total Memory
SIMM 1
SIMM 2
SIMM 3
SIMM 4
80 MB
8 MB
8 MB
32 MB
32 MB
80 MB
32 MB
32 MB
8 MB
8 MB
96 MB
16 MB
16 MB
32 MB
32 MB
96 MB
32 MB
32 MB
16 MB
16 MB
128 MB
32 MB
32 MB
32 MB
32 MB
Interrupt Controller
The interrupt controller operates as an interrupt manager for the entire AT 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 Table Section 1-6. Interrupt-level assignments 0
through 15 are in order of decreasing priority. See Section 2, Setup and Operation, for
information on changing the interrupts using Setup.
Table Section 1-6 Interrupt Level Assignments
Interrupt Priority
Interrupt Device
IRQ00
System Timer
IRQ01
Keyboard
IRQ02
Audio (multimedia configurations only)
IRQ03
COM2
IRQ04
COM1
IRQ05
Audio (multimedia configurations only)
IRQ06
Diskette Drive Controller
IRQ07
Parallel Port LPT1
IRQ08
Clock/Calendar
IRQ09
Audio (multimedia configurations only)
IRQ10
Available
IRQ11
3C509B network adapter (NIC configurations only)
IRQ12
PS/2 mouse
