101-0522 Rabbit Semiconductor, 101-0522 Datasheet - Page 162

• Manufacturer Part Number: 101-0522
• Description: MODULE RABBITCORE RCM3220
• Manufacturer: Rabbit Semiconductor

Specifications of 101-0522

• Module/board Type: MPU Core Module
• For Use With/related Products: RCM3220
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: 101-522; 101-522

D.1.2 Battery-Backup Circuit
Figure D-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 U5, which keeps the 32.768 kHz oscillator working
D.1.3 Reset Generator
The RCM3700 uses a reset generator to reset the Rabbit 3000 microprocessor when the volt-
age drops below the voltage necessary for reliable operation. The reset occurs between
2.85 V and 3.00 V, typically 2.93 V.
The RCM3700 has a reset pin, pin 36 on header J1. This pin provides access to the reset
output from the reset generator, and is also connected to the reset input of the Rabbit 3000
to allow you to reset the microprocessor externally. A resistor divider consisting of R22
and R23 attenuates the signal associated with an externally applied reset to prevent it from
affecting the reset generator.
RabbitCore RCM3700 User’s Manual
the current consumed by the real-time clock and lengthening the battery life.
when the voltage begins to drop.
Figure D-2. RCM3700 Backup Battery Circuit
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