LG -A100 Service Manual page 43

3. TECHNICAL BRIEF
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.
Figure 3.10.2 Block Diagram and System Integration of the KPD
LGE Internal Use Only - 43 - Copyright © 011 LG Electronics. Inc. All right reserved.
Only for training and service purposes