Key And Display Unit - Motorola Cleartone CM5000 Basic Service Manual

OVERVIEW

Key and display Unit

Panel CPU and Peripheral Circuit
Panel CPU (IC001) is communicating with Main CPU in the main unit. It transfer key operation to the
Main CPU and control the LCD based on the command from Main CPU.
CPU contains FLSH ROM, SD RAM interface, ADC, DAC, LCD controller and serial communication.
The Flash ROM (IC003) stores the source code, font data and portrayal bit map data. SDRAM
(IC002) is working area.
The panel CPU communicates with the main unit CPU via buffer IC (IC008). The serial communica-
tion is baud rate 115.2kbps, 8 bits, non parity and 0 V / 3.3 V level.
Temperature sensor IC (IC004) is used for the temperature compensation of the LCD contrast. The
CPU reads the temperature data of temperature sensor by ADC.
White color LED driver IC (IC106) controls the intensity of the LCD back light LED.
The intensity is controlled by the output voltage of the DAC in the CPU.
CPU oscillates clock frequency with crystal (X001) and multiplies 8 times internally.
The core of the CPU operates at 115.2 MHz, Bus clock operates at 57.6 MHz and peripheral block
operate at 28.8 MHz.
Interface
The Connector (J006) connects the Key/Display unit and main unit.
Microphone signal, received signal for handset, hook signal, control signal and power source of
key/display unit are connected to the J006.
Key
Key is switched ON and OFF by metal dome contacts (SW101 to SW124).
SW101 to SW114 and SW116 to SW124 are scanned by key matrix. The emergency key SW115 is
independent input contact.
Keys are back lighted by the blue LEDs. The back light intensity is controlled as 3 levels (OFF - Low
- High) by controlling the transistor (TR107 and TR108) by the control signal of the CPU.
Switch
The power switch and volume control are adjusted by the rotary knob (SW001).
Pushing the rotary knob turns the radio on. Turning the encoder controls the audio volume and
selects the screen menu.
Other than pushing the rotary knob, pressing the emergency button will turn the radio on. In this
case an emergency call will be originated as soon as power on the radio.
CM5000 Mobile Repeater/Gateway - Basic Service Manual 23