Understanding System Features 3-5
8-MB by 32- or 36-bit SIMM (32-MB stick)
16-MB by 32- or 36-bit SIMM (64-MB stick).
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 Chapter 4, NEC Drivers and
Utilities, for information on changing the interrupts using
Setup.
Interrupt Level Assignments
INTERRUPT PRIORITY INTERRUPT DEVICE
NMI
I/O channel check
IRQ00
Reserved, Interval Timer
IRQ01
Reserved, Keyboard buffer full
IRQ02
Reserved, Cascade interrupt from slave
IRQ03
Serial Port 2 (COM2)
IRQ04
Serial Port 1 (COM1)
IRQ05
Audio/LPT2 plug and play option/user available
IRQ06
Diskette Drive Controller
IRQ07
Parallel Port 1 (LPT1)
