Keypad Interface - LG -T315i Service Manual

3.11 Keypad Interface

VRTC
VRTC
3.11 Keypad Interface
R330
6.8K
END_KEY
C332
0.1u
KEY_ROW1
R321
KEY_COL2
R306
KEY_ROW2
R322
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
PWR/HOLD
CN302
1
2
3
VOLUME
CN301
1
680
2
680
3
680
D302 ZD304 ZD305
Figure 3-11-1 MAIN KEY STRUCTURE
3. TECHNICAL BRIEF
POWER ON
END_KEY
D301
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3. TECHNICAL BRIEF
R319
PWRON
1K
R305
100K
Only for training and service purposes