Toshiba e-STUDIO281c Service Manual page 139

3) System diagram
Signals flowing between the control panel and the system board are indicated in the chart below.
When the panel processing CPU detects that the control panel is operated, the operational contents
are transmitted to the System board through the serial data. The state of the equipment and the
messages from the System board are received by the LCD controller and then displayed on the
LCD. The LED and buzzers are switched to ON/OFF with the signals output from the panel process-
ing CPU, based on serial data transmitted from the System control PC board.
System control PC board
4) Data Transmission
FRAME
240
LOAD
FRAME
LOAD
CP
D0-D3
June 2005 © TOSHIBA TEC
Control panel
Power ON/OFF
Reset signals
LCD
controller
Serial data
Fig.5-7
1/tF
1 2 240
CP x(640/4) pulses
Fig.5-8
5 - 13
Inverter for
backlight
Contrast adjustment
circuit
LCD display
640 x 240 dots
Analog
Touch panel
input
Decoder
Panel
processing
CPU
Hard-key matrix
LED driver
LED
Buzzer
1/tF
1 2 240
e-STUDIO281c/351c/451c CONTROL PANEL
1 2
5