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3. TECHNICAL BRIEF
LGE Internal Use Only
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
3.9 Keypad Switching & Scanning
The keypad is controlled by a Key coder IC (PP2106M2). It can be used for scanning keypads up to 8
rows and 8 columns (max 64 keys). PMB8888 control PP2106M2 by KEY_I2C_SCL, KEY_I2C_SDA
and KEY_INT.
Figure 11-1. Keypad Configuration Circuit
(1%)
QWERTY KEY
4.7K
R415
R418 470
R410 470
470R404
2V62_VIO
R403 470
470R412R411 0
C41727p
27pC402
C423 27p
C404 27p
27p C415
C401 0.1uF
C416
C41427p
27p
C41827p
470R409
R414 470
TEST
23
VDD
26
XI
XO
25
R406 470
18
17
P44
P45
16
P46
15
14
P47
13
P50
12
P51
11
P52
P53
10
9
P54
P55
5
P56
4
3
P57
PGND
29
RESETB
27
2
SEL_28P
1
PP2106M2
CLK_SEL
24
GND1
8
GND2
28
P10
22
7
P15
P17
6
21
P40
P41
20
P42
19
P43
U400
R401 0
2V62_VIO
120K
R400
0.1uF
C400
470R416
R417 470
470R419
27pC422
C403 27p
470R405
R402
4.7K
2V62_VIO
C41927p
R407 470
C420 27p
27pC421
2V62_VIO
0R413
27pC424
C41327p
470R420
470R408
KEY_ROW4
KEY_COL4
KEY_COL2
KEY_COL0
KEY_COL7
KEY_COL5
KEY_ROW1
KEY_ROW3
KEY_I2C_SDA
KEY_I2C_SCL
KEY_INT KEY_ROW5
KEY_COL3
KEY_COL1
KEY_COL6
KEY_ROW6
KEY_ROW0
KEY_ROW2