Motorola PM1200, Basic Service Manual

Page: 33 / 138

6880309U09-A October 26, 2007
Basic Theory of Operation : Control Head Assembly 3-3
3.4 Control Head Assembly
3.4.1 Controller
The controller consists of three main components, namely the OMAP Applications Processor, Flash
and SDRAM. The OMAP Applications Processor is the main controller of the control head. Its main
function is to receive inputs from the user and relays the command to the transceiver microprocessor
for processing via Serial Synchronous Interface (SSI) link. The Applications Processor will relay back
any information from the transceiver microprocessor to the user through the Liquid Crystal Display
(LCD). The control head is equipped with an 8MB SDRAM and a 8MB Flash memory for storing and
executing commands.
3.4.2 Power Management (Power Control Microcontroller and Voltage Regulators)
3.4.2.1 Voltage Regulators
The control head utilizes seven different voltage levels to operate correctly, namely 13.4V and 5V.
There are a total of three main regulator ICs to provide the needed voltages.
3.4.3 User Interface (Keypad, STN Display, Volume Selector Knob, Microphone and
Speaker) section
3.4.3.1 Display
The display includes an 8-character alpha-numeric section showing channel and group names, status
and identity information, and error messages, seven icons (OPT, Horn Alert, Public Address/Speaker,
Selectable Tone, Monitor and Scan).
3.4.3.2 Keypad and Volume Selector Knob
The control head assembly processes all menu button inputs and visual indicators through the
application processor. The buttons are programmable to allow different modes of operation through
the CPS.
The Volume Selector Knob allows a linear step of the volume and the Power Button integrates the
On/Off function.
3.4.3.3 Telco Connector
PM1200 currently supports programming through the Telco Connector as well as operation of the
basic palm microphone and keypad microphone.
3.4.3.4 Emergency Microphone
The applications processor operates the emergency microphone if the emergency feature is
activated.
3.4.3.5 Internal Speaker
The control head contains a speaker for the receiver audio. The power source supplying to speaker
is 8 ohms, 1.5 W. The control head speaker can continue functioning even if an external speaker is
connected via the accessory connector.