Technical data

Figure 28: Recommended circuitry for a TX_ON implementation

4.20 Real Time Clock

The real-time clock (RTC) is driven by a 32.768 kHz clock from an internal crystal

oscillator. The clock is divided by 32,768 to generate a clock with a 1 second period

that increments a 29-bit seconds counter. In addition, it can generate interrupts at a

programmed time. The following are the features of RTC:

• 17-year time interval with 1 second resolution.

• Programmed time alarm interrupt

• Alarm output pin

An RTC alarm can be set by loading an appropriate value into the seconds alarm

The RTC relies on an uninterrupted 1.5 V (nominal) power supply (VRTC), whether the

Wireless CPU® is powered off or on. The RTC-alarm operates from the VRTC supply,

and therefore utilizes a 1.5 V logic level. Users have the responsibility to provide a

backup battery to provide uninterrupted VRTC function when the Wireless CPU® is

powered down.

Parameter Condition Min Typ Max Unit

RTC accuracy Ambient (+25±2°C) operation 52.6 Secs/month

RTC accuracy Extreme temperatures 65.2 Secs/month

VRTC

RTC Operational supply voltage

range

1.10 1.50 1.65 V

This document is the sole and exclusive property of WAVECOM. Not to be distributed or divulged without prior written agreement.

Ce document est la propriété exclusive de WAVECOM. Il ne peut être communiqué ou divulgué à des tiers sans son autorisation préalable

GR64 Integrators’ Manual

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