Citizen CL-S400DT - Operation Panel Circuit

Chapter 2 Operating Principles
2-2. Operation of Control Parts
2-25 CL-S400DT
(4) Operation panel circuit
The following is the simplified operation panel circuit. The circuit consists of 1 LED
(Green/Red), 4 switches and 1 LCD.
The LCD is controlled by the signals send from the FPGA (U11). The backlight of LCD is
controlled by BKL-W (White) and BKL-O (Orange) signals sent from the CPU (U1A).
The signals output from the switches are sent to the CPU (U1A).
Green color (POWER indication) and red color (Error indication) of the LED are controlled by
the signal sent from the CPU (U1A).
When PWRSAVE (power saving) signal sent from the CPU (U1A) is “Low”, Q27 and Q28 turn
OFF and +3.3V supply to the LCD is shut off. (Power saving mode is effective if the “Standby
Mode” submenu under the “System Setup” main menu is set to “On”. However, the “Standby
Mode” is set to “Off” at factory default.)
15
14
17
4
13
16
J3
12
11
10
+5V
9
8
7
6
From
U11 (FPGA)
[SA Main PCB]
SW301
SW303
SW304
SW302
D301
5
4
3
2
1
LCDSI
LCDSCK
LCDCD
LCDRST
nLCDCS
BKL-W
BKL-O
[SA LCD PCB]
SW0
SW1
SW2
SW3
LED-G
LED-R
Q27
DTC115EM
Q26
MCH3333
+3.3V
R151
PWRSAVE
R126
From
U1A
CPU
Power Saving Mode
L: Power saving mode ON (+3.3V OFF)
H: Normal mode (+3.3V ON)
3
4
1
4
5
2
J301
6
7
8
9
10
11
12
+3.3V
13
14
15
16
17
Q302
DTC114EM
Q303
DTC114EM
Power LED
Red (Error)
Q301
DTC114EM
Q304
DTC114EM
J302
LCD
+5V
+5V
+5V
PAD301
PAD302
PAD303
LCD
Backlight
BKL-WHITE
BKL-ORANGE
From/to
U1A (CPU)
+3.3V
Anode
Cathode
(White)
Cathode
(Orange)
Green (Power)
PAUSE
FEED
STOP
MENU