Motorola GM328

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Table of Contents
Section 1 Theory of Operation
1.0 Controller Circuits ................................................................................................1-1
1.1 Overview.........................................................................................................1-1
1.2 General...........................................................................................................1-1
1.3 Radio Power Distribution................................................................................1-2
1.4 Electronic ON/OFF.........................................................................................1-4
1.5 Emergency .....................................................................................................1-4
1.6 Mechanical ON/OFF.......................................................................................1-5
1.7 Ignition............................................................................................................1-5
1.8 Microprocessor Clock Synthesizer .................................................................1-5
1.9 Serial Peripheral Interface (SPI).....................................................................1-6
1.10 SBEP Serial Interface.....................................................................................1-7
1.11 General Purpose Input/Output........................................................................1-7
1.12 Normal Microprocessor Operation..................................................................1-8
1.13 FLASH Electronically Erasable Programmable Memory(FLASH EEPROM)1-10
1.14 Electrically Erasable Programmable Memory (EEPROM)............................1-10
1.15 Static Random Access Memory (SRAM)......................................................1-10
2.0 Controller Board Audio and Signalling Circuits..................................................1-11
2.1 General - Audio Signalling Filter IC with Compander (ASFIC CMP)............1-11
2.2 Transmit Audio Circuits ................................................................................1-11
2.3 Transmit Signalling Circuits..........................................................................1-14
2.4 Receive Audio Circuits .................................................................................1-16
2.5 Receive Signalling Circuits...........................................................................1-19
2.6 Voice Storage (optional)...............................................................................1-20
Section 2 Troubleshooting Charts
1.0 Controller Troubleshooting Chart.........................................................................2-1