- 35 -
3. TECHNICAL BRIEF
LGE Internal Use Only
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
3.7 Keypad Switches and Scanning
The key switches are metal domes, which make contact between two concentric pads on the keypad
layer of the PCB when pressed. There are 27 switches (Normal Key 23EA, Volume up down and
camera side key, PWR down side key), connected in a matrix of 6 rows by 5 columns, as shown in
Figure 3-7, except for the power switch (END), which is connected independently. Functions, the row
and column lines of the keypad are connected to ports of AD6721. The columns are outputs, while the
rows are inputs and have pull-up resistors built in. When a key is pressed, the corresponding row and
column are connected together, causing the row input to go low and generate an interrupt. The
columns/rows are then scanned by AD6721 to identify the pressed key.
Figure 3.7 Keypad Switches and Scanning
CAM
7
9
5
CLR
LEFT
MENU
6
DOWN
PWR
#
0
T
SEND
CONF
SEL
UP
8
4
2
*
RIGHT
3
FAV
1
R237
680
SW206
SW203
SW200
SW204
680
R203
SEND
SW210
END
T
CLR
CONF
R240
680
680
R238
SW207
MENU
UP
680
680
R204
R229
varistor
VA200
SHARP
SW208
LEFT
680
R221
R205
680
SW201
680
R226
VA206
varistor
SW209
R200
680
SW205
R232
680
SW202
680
R233
DOWN
SEL
RIGHT
R225
680
680
R223
FAV
VA207
varistor
1
2
3
4
CN200
KEY_COL4
KEY_COL3
KEY_COL2
KEY_COL1
KEY_COL0
KEY_ROW5
KEY_ROW0
KEY_ROW1
KEY_ROW2
KEY_ROW3
KEY_ROW4
POWERKEY
Содержание KP210
Страница 1: ...Date February 2008 Issue 1 0 Service Manual Model KP210 KP215 Service Manual KP210 KP215 ...
Страница 101: ...LGE Internal Use Only Copyright 2008 LG Electronics Inc All right reserved Only for training and service purposes 102 ...
Страница 107: ... 108 LGE Internal Use Only Copyright 2008 LG Electronics Inc All right reserved Only for training and service purposes ...
Страница 121: ...LGE Internal Use Only Copyright 2008 LG Electronics Inc All right reserved Only for training and service purposes 122 ...
Страница 138: ...Note ...
Страница 139: ...Note ...