Backlight And Leds; Backlight; Top Leds; Radio Programming - Motorola MTH500 Service Manual

Backlight and LEDs

Radio Programming

Accessory Connector

68P02963C70-O

Backlight

The keypad backlight consists of 10 green LEDs. There are two more LEDs in the
LCD module that are connected in parallel to the keypad LEDs.

Top LEDs

There are one Green and one Red LEDs, both located on the LCD board. These
LEDs are used as indicators to the radio operation.
The radio is entered into programming mode by setting the MOD pin high level,
and applying a preamble sequence to the radio via the RS232 lines.
The MOD pin assertion is encountered at least 4 CKIH cycles before the negation
of the Reset pin.
The CE bus is intended to support connection to accessories, personal computers,
and test systems. The bus connector has a total of 17 pins, 9 of which have multi-
ple functions. The bus has six basic modes of operation: Normal (also No Acces-
sory Connected), USB Mode, Analog Audio Mode, Phone Powered USB Mode,
RS-232 Mode, and RS-232/SSI Mode (there is also two additional non-standard
modes, DSC and FLASH which are used only for development, factory program-
ming, and debugging). Eight of the 17 pins have different functions depending on
which mode is selected. The other 9 pins always have the same function regardless
of mode.
The mode is selected by applying appropriate logic levels to the Option Select
pins, named OPTION1 and OPTION2. Some of the modes listed above are select-
ed by the additional application of a level on the USB POWER and AUDIO-IN
pins as well.
Theory of Operation
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