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Only for training and service purposes
3. TECHNICAL BRIEF
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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 3-11-3 Block Diagram and System Integration of the KPD
3. TECHNICAL BRIEF