Tait TM8235, Руководство по обслуживанию

Страница: 92 / 578

92 Circuit Descriptions TM8100/TM8200 Service Manual
© Tait Electronics Limited June 2006
3.9 Control-Head Board with Graphical Display
Introduction
This section describes the control-head board for the control head with
graphical display.
For a block diagram of the digital circuitry, refer to Figure 3.14 .
Most signals (except power on/off, speaker and microphone) to and from
the radio body are processed by a RISC processor, which is implemented on
an FPGA on the control-head board. For more information on the RISC
processor and the FPGA, refer to
“Software Architecture” on page 47 .
User Interface
The control-head board includes the circuitry for the following control
elements:
■
ON
/
OFF
key
■
volume potentiometer
■
main keypad (with four functions keys, two scroll keys and
two selection keys)
■
LCD module (with backlighting and optional heating element)
■
three status LEDs
■
two function key LEDs (for function keys
F1
and
F4
)
■
keypad backlighting LEDs
■
speaker.
Connectors
The control-head board includes the circuitry for the following connectors:
■
microphone connector (RJ45 socket)
■
control-head connector (18-way MicroMaTch socket)
■
LCD connector (for internal connection of LCD module)
■
speaker connector (2 leads)
■
soldering pads (2 leads) for an optional concealed microphone
■
control-head options connector (for optional circuit board).
Protection circuitry is provided for the microphone connector. For pinouts
of the control-head connector and the microphone connector, refer to
“Connectors” on page 36 . For more information on the control-head
options connector, please contact Tait Electronics Limited.
ON
/
OFF
Key
When battery power (13.8V) is applied to the radio, a press of the
ON
/
OFF
key
will create an active low signal (
CH ON OFF
) back to the radio body to initiate
the power-on or power-off sequence. This key-press will also be detected
by the FPGA of the control head through Q611 as an active high signal.
For more information on the start-up process, refer to
“Software
Architecture” on page 47 .