101-1272 Rabbit Semiconductor, 101-1272 Datasheet - Page 104

• Manufacturer Part Number: 101-1272
• Description: KIT MESH NETWORK ADD-ON RCM4510W
• Manufacturer: Rabbit Semiconductor
• Type: Microprocessorr

Specifications of 101-1272

• Product: Modules
• Data Bus Width: 12 bit
• Processor Type: Rabbit 4000
• Sram: 512 KB
• Number Of I/os: 20
• Description/function: Computer Module
• Interface Type: Ethernet
• For Use With/related Products: RCM4510W
• Lead Free Status / RoHS Status: Not applicable / Not applicable
• Other names: 316-1158

The drain on the battery by the RCM4510W is typically 7.5 µA when no other power is
supplied. If a 165 mA·h battery is used, the battery can last about 2.5 years:
The actual battery life in your application will depend on the current drawn by components
not on the RCM4510W and on the storage capacity of the battery. The RCM4510W does not
drain the battery while it is powered up normally.
Cycle the main power off/on after you install a backup battery for the first time, and when-
ever you replace the battery. This step will minimize the current drawn by the real-time
clock oscillator circuit from the backup battery should the RCM4510W experience a loss
of main power.
Rabbit’s Technical Note TN235, External 32.768 kHz Oscillator Circuits, provides addi-
tional information about the current draw by the real-time clock oscillator circuit.
C.1.2 Battery-Backup Circuit
Figure C-2 shows the battery-backup circuit.
The battery-backup circuit serves three purposes:
• It reduces the battery voltage to the SRAM and to the real-time clock, thereby limiting
• It ensures that current can flow only out of the battery to prevent charging the battery.
• A voltage, VOSC, is supplied to U11, which keeps the 32.768 kHz oscillator working
C.1.3 Reset Generator
The RCM4510W uses a reset generator to reset the Rabbit 4000 microprocessor when the
voltage drops below the voltage necessary for reliable operation. The reset occurs between
98
the current consumed by the real-time clock and lengthening the battery life.
when the voltage begins to drop.
NOTE: Remember to cycle the main power off/on any time the RCM4510W is removed
165 mA·h
----------------------- -
7.5 µA
from the Prototyping Board or motherboard since that is where the backup battery
would be located.
=
Figure C-2. RCM4510W Backup Battery Circuit
2.5 years.
W
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RabbitCore RCM4500W