| 摘要 |
An input key apparatus comprises a keyboard including a plurality of keys and generating key signals when keys are pressed and a key input decoder receiving the key signals from the keyboard for generating decoded key signals. The key input decoder also generates a single key depression signal when a key of the keyboard is pressed one time, and a multi-key depression signal when two or more keys of the keyboard are simultaneously pressed. A chattering prevention circuit receives the single key depression signal and the multi-key depression signal for determining on the basis of the received signals whether or not the key signal received by the decoder is valid, for the purpose of generating a key input valid signal. An output circuit receives the decoded key signals for latching the decoded key signal in response to the key input valid signal.
|
