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Application filed by United Microelectronics CorpfiledCriticalUnited Microelectronics Corp
Priority to TW82109865ApriorityCriticalpatent/TW223195B/en
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Publication of TW223195BpublicationCriticalpatent/TW223195B/en
A method to detect additional functions of keypad by using the existingI/O ports to detect the states of resistors attached to the ports, wherethe state is connected to power, ground or floating, comprises thefollowing steps: 1. Whenever a keypad is depressed, the output of the keypad scanningcircuit is hold for a period of time; 2. During the period, proceeding detecting the attached resistors'statesfor column I/O ports or row I/O ports and sending the detected data toa memory device for deciding the attached resistors' states for columnI/O ports or row I/O ports; 3. Stopping detecting the attached resistors' states and releasing thekeypad scanning circuit to continue the scanning.
TW82109865A1993-11-231993-11-23Method and apparatus to detect additional functions of keypad
TW223195B
(en)