Motorola CM340 Сервісна інформація - Сторінка 7

Переглянути онлайн або завантажити pdf Сервісна інформація для Двостороннє радіо Motorola CM340. Motorola CM340 26 сторінок. Commercial series controlhead
Також для Motorola CM340: Посібник користувача (24 сторінок), Посібник користувача (5 сторінок), Посібник користувача (12 сторінок)

1.0

This Chapter provides a detailed theory of operation for the Controlhead circuits. For details of the

trouble shooting refer to the related chapter in this section.

2.0

The controlhead contains the internal speaker, the on/off/volume knob, the microphone connector,

several buttons to operate the radio and three indicator Light Emitting Diodes (LED) to inform the

user about the radio status and a 7-segment display for numeric information.

7-segment

display

DTMF

Resistors

Keypads

2.1

The power supply to the control head is taken from the host radio's 9.3V via connector J803-9, The

9.3V is used for the LEDs and back light, the 5V is used for the LCD driver and level shifter. The

stabilized 3V is used for the other parts.

2.2

The host radio (master) communicates with the control head through its SPI bus. Three lines are

connected to the shift register (U801):SPI clock (J803-17), SPI MOSI (J803-16) and shift register

chip select (J803-15).

BCD To

7-segment

Control line

Boot_res / SCI

Mux.

Control

DTMF

Row/Column

9.3V

Keypad

Backlight

THEORY OF OPERATION

9.3V

Shift

PTT

circuit

Boot_res (DTMF-

Column)/ SCI

(DTMF-Row)

Chapter 2

2 pin speaker

connector