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3.11 Keypad Interface
KEY_IN[1]
R411
680
KEY_IN[3]
R414
680
KEY_OUT[2]
R415
680
KEY_OUT[3]
R416
680
The Keypad Interface is a peripheral controller, which can be used for scanning external keypad matrices with
up to 8 rows and 8 columns (that is 64 standard keys). By adding an additional row of keys connected to
ground the number of keys can be extended by up to 8 keys. This results in a maximum number of 72 keys to
by identified by the Keypad Interface Controller.
The Keypad Scan Module reduces the number of interrupts and polling through the processor and therefore
reduces the power consumption. The module is able to debounce and scan the external keypad matrix
automatically without any software intervention. After debouncing it generates an interrupt. The interface
controller contains information about the key (or key combination) that was pressed and how long it was
pressed.
LGE Internal Use Only
OK
SEND
KB402
KB401
CLR
KB403
D403
D401
D402
Figure 3-11-1 MAIN KEY STRUCTURE
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3. TECHNICAL BRIEF
VA402
VA401
CN403
1
2
3
Copyright © 011 LG Electronics. Inc. All right reserved.
Only for training and service purposes
CN404
1
2
3
4
VBACKUP_BAT
R410
6.8K
PWR_HOLD
ZD401
C413
0.1u
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