Motorola GM-950

Theory of Operation 5C.3-i
Chapter 5C.3
Theory of Operation
Table of Contents
Table of Contents
Paragraph Page
1.0 Overview..................................................................................................... 1
2.0 Open Controller.......................................................................................... 1
2.1 General........................................................................................................ 1
2.2 Voltage Regulators ...................................................................................... 1
2.3 Electronic On/Off ......................................................................................... 2
2.4 Emergency................................................................................................... 3
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 Board 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