Interrupt Configuration
36 – Configuration
VL-486-4 Reference Manual
Table 14: Interrupt Request Inputs
Interrupt
Signal
Name
Interrupt
Number
Typical Source
of Interrupt on
an IBM AT
As Shipped
Configuration
Notes
IRQ8
70h
Real Time
Clock
Hardwired
Internal signal, not available to
the outside world. Can be used
for alarms or periodic interrupts.
IRQ9
71h
Unassigned
Hardwired
Hardwired to STD Bus INTRQ*.
IRQ10
72h
Unassigned
No Connection
Not available. Non-DOS users
should mask this interrupt.
IRQ11
73h
Unassigned
INTRQ2*
IRQ11 can receive interrupts
from STD Bus INTRQ2* or from
the Front-Plane connector J5
(FPI2).
IRQ12
74h
Unassigned
INTRQ3*
IRQ12 can receive interrupts
from STD Bus INTRQ3* or from
the Front-Plane connector J5
(FPI3).
IRQ13
75h
Math
Coprocessor
No Connection
Internal signal, not available to
the outside world. Non-DOS
users should mask this interrupt.
IRQ14
76h
Hard Disk
Drive
No Connection
Internal signal, not available to
the outside world.
IRQ15
77h
Unassigned
CIO Chip
IRQ15 can receive interrupts
from the on-board Counter/Timer
#2 or from the Digital I/O
circuitry.