Interrupt Configuration
VL-486-4 Reference Manual
Configuration – 35
CPU I
NTERRUPT
R
EQUEST
I
NPUTS
The seventeen standard IBM compatible interrupt inputs (IRQs) are shown below.
Table 14: Interrupt Request Inputs
Interrupt
Signal
Name
Interrupt
Number
Typical Source
of Interrupt on
an IBM AT
As Shipped
Configuration
Notes
NMI
—
Parity Check
and IOCHCK
from ISA Bus.
Hardwired
STD Bus NMIRQ* routed to CPU
NMI input, but can be
disconnected by removing a
jumper.
IRQ0
08h
Timer 0
Hardwired
Internal signal, not available to
the outside world.
IRQ1
09h
Keyboard
INTRQ1*
DOS/BIOS expects keyboard
interrupts on this input. Comes
from STD Bus via INTRQ* or
INTRQ1*. The interrupt jumper
on the VL-SVGA-1 must match.
IRQ2
0Ah
Slave Interrupt
Controller
Hardwired
Internal signal, not available to
the outside world.
IRQ3
0Bh
COM2
COM2
DOS/BIOS usually expects
COM2 interrupts on this input.
Comes from the on-board COM2
circuitry or via Front-Plane
connector J5 (FPI1).
IRQ4
0Ch
COM1
COM1
Internal signal, not available to
the outside world.
IRQ5
0Dh
LPT 2
Hardwired
IPC Interrupts.
IRQ6
0Eh
Floppy Disk
No Connection
Internal signal, not available to
the outside world. Non-DOS
users should mask this interrupt.
IRQ7
0Fh
LPT1
Hardwired
Internal signal, not available to
the outside world.