Keypad Interface - LG GX300 Service Manual

3. TECHNICAL BRIEF

3.12 Keypad Interface

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
Not Mount
Figure 3.12.1 MAIN KEY STRUCTURE
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3. TECHNICAL BRIEF
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