
Jumper Configurations
Table A-1
Jumper Descriptions (continued).
JUMPER #
DESCRIPTION
W50(A,B)
Install jumper W50A to bring the interrupt
output (INT) from the on-board 8259A to the
CPU interrupt input (INT). Install W50B to
bring
the
STD
bus
interrupt
request
(INTRQ*), inverted once, directly to the
CPU INT input. This disconnects the on-
board 8259A INT. Do this when using an
off-board master 8259A with or without
slaves. Factory default installs W50A.
W50A
W50B
Function
IN †
OUT
8259A drives CPU interrupt input
OUT
IN
INTRQ* STD bus signal drives CPU
interrupt input, bypassing the 8259A
A-36