101-0402 Rabbit Semiconductor, 101-0402 Datasheet - Page 67

• Manufacturer Part Number: 101-0402
• Description: KIT DEV TCP/IP 2000 INTL
• Manufacturer: Rabbit Semiconductor
• Series: RabbitCore 2000r
• Type: MPU Moduler

Specifications of 101-0402

• Contents: RabbitCore Module, Dev. Board, Cable and Dynamic C® CD-Rom
• For Use With/related Products: RCM2000, RCM2010, RCM2020
• Lead Free Status / RoHS Status: Vendor undefined / Vendor undefined

B.2.1 Battery-Backup Circuit
Figure B-3 shows the battery-backup circuitry on the TCP/IP Development Board.
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 U13, which keeps the 32.768 kHz oscillator working
VRAM and Vcc are nearly equal (<100 mV, typically 10 mV) when power is supplied to
the TCP/IP Development Board. VRAM is also available on pin 34 of header J2 to facili-
tate battery backup of the external circuit. Note that the recommended minimum resistive
load at VRAM is 100 k , and new battery life calculations should be done to take external
loading into account.
Getting Started
the current consumed by the real-time clock and lengthening the battery life.
when the voltage begins to drop.
Figure B-3. TCP/IP Development Board Battery Backup Circuit
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thermistor
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