Real Time Clock - Motorola GP Series Detailed Service Manual

Professional portable radio uhf 800mhz dsm

Hide thumbs Also See for GP Series:

Table of Contents

Controller Circuits

Conventional MDC

Conventional 5 Tone

Privacy Plus

Real Time Clock

(Refer to Figure 1-3 and the Microprocessor schematic diagram)

Radios with displays support a Real Time Clock (RTC) module for purposes of message time

stamping and time keeping. The RTC module resides in the microcontroller.The clock uses a back-

up Lithium Ion battery for operating power when the primary battery is removed.

Circuit Description

The RTC module circuit, shown in Figure 1-3, is powered by the ModB/Vstby pin and PI6/PI7 from

the crystal oscillator circuit. A clock frequency of 38.4kHz from a crystal oscillator provides the

reference signal which is divided down to 1 Hz in the processor.

Table 1-1 Radio Memory Requirements

GP320, GP330,

GP360, GP380

GP240, GP280

GP540, GP580

GP640, GP680

Figure 1-3 RTC Circuit

Show Quick Links

Table of Contents