Specifications

2.7 Installing and Replacing the Battery
The on-board Real-Time Clock, CMOS memory and Non-volatile SRAM are powered by a 3.3V
Lithium battery when the board is powered off. It is advisable, though not essential, for the
battery to be fitted prior to using the board. Figure 2-8 shows how to do this. One battery is
supplied with the board, but it is not normally fitted.
The battery should be replaced when the voltage falls below 2.6V. If data retention is important
during this process the board must have at least the VME 5V Standby supply available during
the change. In order to reset the battery monitoring circuitry the battery must be removed for at
least 7 seconds and replaced.
Depending on the way in which the board is operated and stored, battery life should be in excess
of 2 years. The life expectancy will fall if the battery is subjected to long periods at temperatures
of 45
o
C or above. It will also fall if the battery is fitted to a board that is stored in it’s conductive
bag even at room temperature.
2-10 VP 110/01x
Hardware Installation
+
BR2032
Top is marked positive
Bottom is ne
g
ative
snap in /
lever out
LK5 CMOS Clear
Normal
Operation
Clear
RAM
Figure 2-8 Battery Fitting and CMOS Clear Jumper