Keyboard scanning and interface method and circuit
First Claim
1. A method for communicating keyed input information comprising the steps of:
- scanning a keyboard to detect activated keys;
memorizing said activated keys;
generating from the memorized keys a binary word having a bit length defined by the number of activated keys detected during one scan of said keyboard, said word having an identifiable byte corresponding to each of said memorized keys; and
communicating said binary word.
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Accused Products
Abstract
A method and apparatus is disclosed for allowing simultaneous depression or chording of a multiple number of keys on a keyboard coupled through an interface circuit to a computer operating system. An arbitrary association can be made to the chord which is distinct from the association made with its component keys. A dedicated processor system in the keyboard peripheral scans and stores in a dedicated memory the identity of all keys detected in the depressed state during the scan of the keyboard. For transmission to the computer operating system, each key depression detected during the scan is represented as an 8-bit binary component and the most significant bit of each binary component is set to the same one of the two permissible binary values, except for the most significant bit of the binary component representing the last depressed key detected during the scan of the keyboard. The most significant bit of that component is set to other of the two permissible binary values.
30 Citations
14 Claims
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1. A method for communicating keyed input information comprising the steps of:
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scanning a keyboard to detect activated keys; memorizing said activated keys; generating from the memorized keys a binary word having a bit length defined by the number of activated keys detected during one scan of said keyboard, said word having an identifiable byte corresponding to each of said memorized keys; and communicating said binary word. - View Dependent Claims (2, 3, 4, 5)
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6. A method for communicating keyed input information from a keyboard to a data processing system comprising the steps of:
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cyclically scanning each row of keys of a plurality of rows forming the keyboard; detecting the activated keys within the scanned row; generating a memory address for each activated key; addressing a first memory with said memory address; storing a representation of each activated key at a portion of said first memory corresponding to said generated address translating each representation stored in said first memory into a second memory as a unique code including a series of binary bits; and
reading out said bits to create a binary word having a bit length defined by the number of activated keys detected during one scan cycle. - View Dependent Claims (7, 8)
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9. A keyboard communication circuit coupled to a plurality of keys of a keyboard, comprising:
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scanning means for addressing said plurality of keys and for detecting the activation status of each one of said keys; memory means coupled to said scanning means for storing a first representation of each activated key detected during the addressing of the plurality of keys; means, coupled to said memory means, for generating from said stored first representations a distinct further representation in the form of a binary word having a bit length determined by the number of activated keys detected during one addressing of said plurality of keys, said word having an identifiable byte corresponding to each of said memorized keys; and means for communicating said word. - View Dependent Claims (10, 11, 12, 13)
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14. An apparatus for communicating keying input data to a data processing system comprising:
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scanning means for interrogating the keys of the keyboard and for detecting activated keys; memory means coupled to said scanning means for storing codes associated with detected activated keys; means for generating a binary word comprising a number of stored codes, one such code corresponding to each activated key detected during one interrogation of the entire keyboard; and means for communicating said word.
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Specification