4-10 Product Principle
3. TGC board implements the fix of TCG’s sliding rheostat.
4. Trackball sub-module communicates with the host via USB.
5. Sub-module of QWERTY keyboard adopts “thin film + silicon keys + structure keys” to
implement the standard keyboard.
6. Buzzer sub-unit adopts PWM waveforms that FPGA outputs to control the length and sound of
volume and frequency.
4.8 Main Display Unit
Test board
of
environment
brightness
Parameter
board
+12V+3.3V
LVDS
3.3V
I2C
Backlight
control
3.3V
I2C
Main board socket
15.6"
1920*1080
LCD Monitor
LTBC
LTBC
LTBC
LTBC
Fig 4-8 Principle diagram of monitor
The monitor unit consists of LCD screen, connecting wires, parameter board, environmental light
detecting board, etc.
Function description:
To make the display effect of LCD screen equal to that on the parameter board, parameter
board stores color temperature and gamma calibration data. It is necessary to update the
parameters in control panel for first time machine assembly or control panel/LCD screen
replacements.
Signal processing FPGA calibrates the video signal that CPU board outputs based on the
information from parameter board, and then drives LCD display screen. Brightness and power
supply of LCD display screen are also controlled by this FPGA.
Environmental light detecting board detects the brightness level of environment. To achieve
better display effect, main unit adjusts LCD brightness level according to the environment.