 Portable computer keyboard |
| OF THE INVENTION As depicted in FIG. 1, the portable computer keyboard 10 of the present invention ... |
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| Keyboard-type input apparatus |
| The unique points in the present invention are that fifteen keys in the three-line and five-column ... |
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| Method and apparatus for non-contacting information transmission |
| It is therefore the object of the present invention to provide an apparatus for non-contacting ... |
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| Capcitively coupled bi-directional data and power transmission system |
| Accordingly, a power and data transfer system is provided which includes a portable device with a ... |
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| Method of producing a tag device with IC capacitively coupled to antenna |
| It is therefore an object of the present invention to provide a tag device substantially free from ... |
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| Detachable case for an electronic organizer |
| The present invention comprises a personal information system unit detachable case. This case has a ... |
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| Method and apparatus for allowing a personal computer to control one or more devices |
| It is an object of the present invention to provide a wireless interface controller that enables a ... |
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| Burner assembly having a shielded porcelain burner bowl |
| In accordance with one aspect of the present invention, a burner assembly for a cooking appliance ... |
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| Tag responsive to high-frequecy for varying capacitance of tuning capacitor |
| This invention aims to provide a RF-TAG capable of obtaining an optimum supply voltage and an ... |
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Pin-reduced low power keyboard scanner
| Details |
Inventors: Niot, Francois;
Assignee: VLSI Technology, Inc. (San Jose, CA)
Primary Examiner: Horabik; Michael
Assistant Examiner: Edwards, Jr.; Timothy
Attorney, Agent or Firm: Merchant, Gould, Smith, Edell, Welter & Schmidt, P.A.
An arrangement for providing key switch actuation detection which reduces the number of key switch inputs required at a key switch controller. A key scanning system for detecting the activation of keys on a key-based input device is provided, having a plurality of logic level sensors to detect and temporarily store logic levels on corresponding connection nodes. A plurality of switches, each coupled to one of the keys, provides a pattern of logic levels on the connection nodes in response to the activation of a particular key. A logic monitor is coupled to the logic level sensors to detect the stored logic levels and recognize the activation of the particular key based on the pattern of the stored logic levels. A method for performing key switch actuation detection that reduces the number of required key switch inputs is also provided. |
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DETAILED DESCRIPTION The present invention is directed to a system and method for providing key switch actuation detection which reduces the number of key switch inputs required at a key switch controller.
In accordance with one embodiment of the invention, a key scanning system for detecting the activation of keys on a key-based input device is provided.
A plurality of logic level sensors detect and temporarily store logic levels on corresponding connection nodes.
A plurality of switches, each coupled to one of the keys, provides a pattern of logic levels on the connection nodes in response to the activation of a particular key.
A logic monitor is coupled to the logic level sensors to detect the stored logic levels and recognize the activation of the particular key based on the pattern of the stored logic levels.
In accordance with another embodiment of the invention, a method for detecting the actuation of switches in a key-based input device is provided.
The method includes imparting a unique pattern of logic levels onto a plurality of nodes upon actuation of one of the switches.
The unique pattern of logic levels on the plurality of nodes is temporarily stored, and the nodes are periodically monitored.
The stored logic levels are compared to a plurality of known binary patterns to determine which of the switches has been actuated by matching the patterns of stored logic levels to one of the known binary patterns.
In a more specific embodiment of the invention, an activated-key detecting arrangement is provided for use with a keyboard/keypad control circuit.
The arrangement includes Y send-return lines, where each of N keys is assigned to at least two send-return lines.
A set of Y level-maintaining circuits is also provided, where each of the level-maintaining circuits is assigned and coupled to a send-return line and arranged to maintain a logic level on the assigned send-return line.
N switches are coupled to at least two send-return lines.
A control circuit is coupled to the Y send-return lines, and is configured to drive a first logic level onto one of the Y send-return lines, drive a second logic level onto the remaining (Y-1) of the Y send-return lines, and detect a logic state imparted on the one of the Y send-return lines by driving the second logic level from one of the remaining (Y-1) send-return lines onto the Y send-return line, where any of the N keys corresponding to the remaining (Y-1) send-return lines had been activated
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