
Jumper Configurations
Table A-1
Jumper Descriptions (continued).
JUMPER #
DESCRIPTION
W53
Install W53 to enable the ZT 8809A to drive
the STD bus signal DCPWRDWN*, pin 6,
when DC power is failing. The ZT 8809A
can detect DC power failure and AC power
failure with the optional AC transformer.
The DCPWRDWN* is sent to allow other
boards in the system to protect their static
RAM at the same time as the processor.
Removing W53 prevents the ZT 8809A from
driving the DCPWRDWN* signal. Factory
default installs this jumper.
Note: Be sure to remove this jumper if another
board, such as the ZT 8882, is driving this
backplane signal.
W53
Function
IN †
AC power-fail detect logic drives
DCPWRDWN* on STD bus
OUT
DCPWRDWN* STD bus signal not
driven
A-39