Jumper Configurations
Table A-1
Jumper Descriptions (continued).
JUMPER #
DESCRIPTION
W67
Installing jumper W67 connects the parallel
port signal SLIN* to the memory decoder.
This allows 256K EPROMs to be used in
socket 5D1 in conjunction with 640K of
system RAM. Writing a "1" to bit 3 of the
Line Printer Control Register allows access
to the lower 128K of a 256K EPROM placed
in socket 5D1. Jumpers W55 and W56 must
also be selected correctly for a 256K device.
Refer to the "Memory Addressing" table for
jumpers W55-59 on pages A-42 to A-44.
Factory default installs W67. The location of
W67 is shown in Figure A-11 on page A-34.
W67
Function
IN †
Enables software control/access to the lower half
of 256K EPROMs in socket 5D1 when the board
is configured with 640K of system RAM
OUT
Disables access to the lower half of 256K
EPROMs in socket 5D1 when the board is
configured with 640K of system RAM
A-52
