Specifications

Jumper Configurations
Table A-1
Jumper Descriptions (continued).
JUMPER # DESCRIPTION
W38(A,B) Install jumper W38A to battery back the
RAM 3/EPROM 0 socket at 3D1. This is
possible only when a CMOS static RAM is
installed in the socket. Install jumper W38B
to tie pin 16 of that socket directly to ground.
Factory default installs W38B.
Note: Since the RAM in 3D1 is a possible loca-
tion for a RAM drive in a 640 Kbyte system,
jumper W38A allows independent battery backup
of a RAM drive. The drive can be up to
112 Kbytes for a 128 Kbyte battery-backed
RAM, allowing for software overhead.
W38A W38B Function
IN OUT Battery back the RAM in socket 3D1
OUT IN † No battery backup of RAM/EPROM
in 3D1
A-28