Distributor of Digi International: Excellent Integrated System Limited
Datasheet of 101-1274 - KIT DEV STANDARD RCM5700
Contact us: [email protected] Website: www.integrated-circuit.com
MiniCore RCM5700/RCM6700 User’s Manual
digi.com
106
The actual life in your application will depend on the current drawn by components not on the
RCM5700/RCM6700 and on the storage capacity of the battery. The RCM5700/RCM6700 does
not drain the battery while it is powered up normally.
Cycle the main power off/on on the MiniCore after you install a backup battery for the first time,
and whenever you replace the battery. This step will minimize the current drawn by the real-time
clock oscillator circuit from the backup battery should the MiniCore experience a loss of main
power.
NOTE:
Remember to cycle the main power off/on any time the MiniCore is removed from the
Interface Board or motherboard since that is where the backup battery would be located.
Rabbit’s Technical Note TN235,
External 32.768 kHz Oscillator Circuits
, provides additional
information about the current draw by the real-time clock oscillator circuit.
G.1.2 Battery-Backup Circuit
Figure G-2 shows the battery-backup circuit.
Figure G-2. MiniCore Backup Battery Circuit
The battery-backup circuit serves the following purposes:
•
It reduces the battery voltage to real-time clock, thereby limiting the current consumed by the
real-time clock and lengthening the battery life.
•
It ensures that current can flow only
out
of the battery to prevent charging the battery.
•
Switches to battery power only when the +3.3 V system power supply is off.
G.1.3 Reset Generator
The RCM5700/RCM6700 uses a reset generator to reset the Rabbit microprocessor when the
voltage drops below the voltage necessary for reliable operation. The reset occurs between 2.85 V
and 3.00 V, typically 2.93 V. The MiniCore has a reset output on the edge connector.
107 / 113
107 / 113
