LG -A258 Service Manual page 54

3. TECHNICAL BRIEF
Figure 3.13.1 Block Diagram and System Integration of the KPD
Features of the Keypad Interface Controller
• Synchronous to bus
• 32 bit AHB bus interface
• 32.768 kHz sample clock
• Debouncing process (0 to 100 ms, 10 ms resolution) duration programmable by controller
• Module sends an interrupt, whenever a change occurs
• Up to 8 rows and 8 columns of a standard keypad matrix possible
• Up to 8 additional keys connected to ground possible
• Pressed key (or combination of pressed keys) and duration (0 to 1 s, 10 ms resolution) stored within keypad
registers
• Rescan (0 to 100 ms, 10 ms resolution) to determine that pressed key(s) still the same.
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