User`s manual

118 MiniCore RCM5600W
F.1.1 Battery Backup
The RCM5600W does not have a battery, but there is provision for a customer-supplied
battery to keep the Rabbit 5000 real-time clock running.
The edge connector, shown in Figure F-1, allows access to the external battery. This
makes it possible to connect an external 3 V power supply. This allows the internal Rabbit
5000 real-time clock to retain data with the RCM5600W powered down.
Figure F-1. External Battery Connections
A lithium battery with a nominal voltage of 3 V and a minimum capacity of 165 mA·h is
recommended. A lithium battery is strongly recommended because of its nearly constant
nominal voltage over most of its life.
The drain on the battery by the RCM5600W is typically 5 µA when no other power is
supplied. If a 165 mA·h battery is used, the battery can last about 3.75 years:
GND
n.c.
n.c.
LNK
PE0
PE2
PE5
PE7
PD0
PD2
PC0
PC2
PC4/TxB
PB0/SCLK
PB2
PB4
PB6
PA0
PA2
PA4
PA6
/IORD
/IOWR
STATUS
SMODE
GND
1
51
2
52
+3.3 V
n.c.
n.c.
ACT
PE1
PE3
PE6
/RESET_IN
PD1
PD3
PC1
PC3
PC5/RxB
/RESET
PB3
PB5
PB7
PA1
PA3
PA5
PA7
VBAT_EXT
PB1/CLKA
PC6/TxA
PC7/RxA
+3.3 V
Bottom
Top
External
Battery
n.c. = not connected
165 mA·h
5 µA
------------------------3.75 years.=