Patent ID: 6859150

Claim:
An apparatus for reading keyboard-commands of a portable computer, comprising: a shift register for outputting a plurality of scan-input signals and a reference signal according to an initial signal and a clock signal; a keyboard-matrix circuit coupled to the shift register for outputting a scan-output signal according to the scan-input signals, wherein said keyboard-matrix circuit includes a plurality of nodes and each of buttons of said keyboard is corresponded to one of said nodes; a filter coupled to the keyboard-matrix circuit for filtering noise of the scan output signal, outputting a filter signal according to the scan-output signal; a buffer coupled to the filter for further stabilizing said filter signal, outputting a buffer signal according to the filter signal; an address generator coupled to the shift register and said buffer respectively for receiving said reference signal and outputting an address signal according to the buffer signal; a mapping device coupled to the address generator for outputting a mapping signal according to the address signal; a comparator coupled to the mapping device for outputting a comparing signal according to the mapping signal and a plurality of status data, wherein said comparator includes a plurality of status storage registers for storing said corresponding status data respectively; and a outputting device coupled to the comparator for outputting a data clock signal and a data output signal according to the comparing signal.