Motorola GM1200E, Service Manual

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Introduction/Theory of Operation 3.1-i
Chapter 3.1
Introduction/Theory of Operation
Table of Contents
Table of Contents
Paragraph Page
1.0 Introduction ................................................................................................ 1
2.0 Open Controller .......................................................................................... 1
2.1 General ........................................................................................................ 1
2.2 Voltage Regulators ...................................................................................... 1
2.3 Electronic On/Off ......................................................................................... 2
2.4 Emergency................................................................................................... 2
2.5 Mechanical On/Off ....................................................................................... 3
2.6 Ignition ......................................................................................................... 3
2.7 Hook RSS .................................................................................................... 3
2.8 Microprocessor Clock Synthesizer .............................................................. 4
2.9 Serial Peripheral Interface (
SPI
) ................................................................... 4
2.10 SPEB Serial Interface .................................................................................. 5
2.11 General Purpose Input/Output..................................................................... 6
2.12 Normal Microprocessor Operation ............................................................... 6
2.13 FLASH Electronically Erasable Programmable Memory (
FLASH EEPROM
) .. 8
2.14 Electrically Erasable Programmable Memory (
EEPROM
) ............................. 8
2.15 Static Random Access Memory (
SRAM
)....................................................... 9
Controller Audio and Signalling Circuits
3.0 General ....................................................................................................... 9
3.1 Audio Signalling Filter IC (
ASFIC
) ................................................................. 9
3.2 Audio Ground............................................................................................... 9
4.0 Transmit Audio Circuits ........................................................................... 10
4.1 Mic Input Path............................................................................................ 10
4.2 External Mic Path....................................................................................... 11
4.3 PTT Sensing and TX Audio Processing .................................................... 11
4.4 TX Secure Audio (optional)........................................................................ 11