Patent US3279804A successfully refreshed from Google Patents.
Patent US2344467A successfully refreshed from Google Patents.
US5235331A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Key scanning apparatus
Assignee: Toshiba Corp
•
Filing: 1991-05-28
•
Granted: 1993-08-10
•
Expires: 2011-05-28
Abstract
Abstract A key scanning apparatus includes display control circuit for receiving display data and for generating a display control signal which includes display timing periods for driving a display and key scan timing periods for scanning a key matrix. The display timing periods and the key scan timing periods appear in the display control signal in a time sharing manner. The key scanning apparatus also includes a key scan control circuit for outputting a key scan signal to scan the key matrix on the basis of the display control signal and selector for selectively applying either one of the display control signal and the key scan signal to data transfer lines. When the selector outputs the display control signal to the data transfer lines, transfer display data is transferred, and when the selector outputs the key scan signal to the transfer lines, key scan data is transferred. An interrupt control circuit is also provided which generates and outputs a key scan interrupt request signal to the CPU and a key data hold circuit is also provided which receives and holds key data from the key matrix in synchronism with the key scan signal, applies the held data to the CPU, and generates a key scan inhibit signal to inhibit the succeeding key scan operation until the held key data is read by the CPU.
Inventors
- 👤 Kazuya Sato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 10:28
CPC Classifications
H; H03; H03M; H03M11/00; H03M11/20
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
237 words
A key scanning apparatus for a computer system having a CPU, a key matrix and display, said apparatus comprising: display control means for receiving display data and for generating a display control signal which is comprised of display timing periods to drive said display and key scan timing periods to scan said key matrix, said display timing periods and said key scan timing periods appearing in a time sharing manner; key scan control means for outputting a key scan signal to scan said key matrix on the basis of said display control signal; selecting means for selectively applying either one of said display control signal and said key scan signal to data transfer lines which operate as display data transfer lines when said selecting means outputs said display control signal and as key scan data transfer lines when said selecting means outputs said key scan signal; interrupt control means for generating and outputting a key scan interrupt request signal to the CPU in such a way as to be readable by the CPU; and key data hold means for receiving and holding key data output from the key matrix in synchronism with the key scan signal, for applying the held data to the CPU so as to be readable by the CPU, and for generating a key scan inhibit signal to inhibit a succeeding key scan operation until the held key data is read by the CPU.
Claim 2
Dependent Claim
237 words
A key scanning apparatus for a computer system having a CPU, a key matrix and display, said apparatus comprising: display control means for receiving display data and for generating a display control signal which is comprised of display timing periods to drive said display and key scan timing periods to scan said key matrix, said display timing periods and said key scan timing periods appearing in a time sharing manner; key scan control means for outputting a key scan signal to scan said key matrix on the basis of said display control signal; selecting means for selectively applying either one of said display control signal and said key scan signal to data transfer lines which operate as display data transfer lines when said selecting means outputs said display control signal and as key scan data transfer lines when said selecting means outputs said key scan signal; interrupt control means for generating and outputting a key scan interrupt request signal to the CPU in such a way as to be readable by the CPU; and key data hold means for receiving and holding key data output from the key matrix in synchronism with the key scan signal, for applying the held data to the CPU so as to be readable by the CPU, and for generating a key scan inhibit signal to inhibit a succeeding key scan operation until the held key data is read by the CPU.
Claim 3
Dependent Claim
22 words
The key scanning apparatus of claim 1, further comprising key scan position holding means for holding a key scan position decode signal.
Claim 4
Dependent Claim
308 words
A key scanning apparatus for a computer system having a CPU, a key matrix and display, said apparatus comprising: display control means for receiving display data for generating a display control signal which is comprised of display timing periods to drive said display and key scan timing periods to scan said key matrix and for generating a display data signal, said display timing periods and said key scan timing periods appearing in a time sharing manner; key scan control means for receiving said display control signal and for outputting a key scan signal to scan said key matrix on the basis of said display control signal; selecting means for receiving and for selectively applying either one of said display data signal and said key scan signal to data transfer lines which operate as display data transfer lines when said selecting means outputs said display data signal and as key scan data transfer lines when said selecting means outputs said key scan signal, said display data transfer lines transferring display data to said display so that a character corresponding to said display data is displayed by said display and said key scan data transfer lines transferring key scan data to said key matrix such that operation of said display is interrupted; interrupt control means for generating and outputting a key scan interrupt request signal to the CPU in such a way as to be readable by the CPU; and key data hold means for receiving and holding key data output from the key matrix in synchronism with the key scan signal, for applying the held data to the CPU so as to be readable by the CPU, and for generating and sending a key scan inhibit signal to said display control means to inhibit a succeeding key scan operation until the held key data is read by the CPU.
Claim 5
Dependent Claim
308 words
A key scanning apparatus for a computer system having a CPU, a key matrix and display, said apparatus comprising: display control means for receiving display data for generating a display control signal which is comprised of display timing periods to drive said display and key scan timing periods to scan said key matrix and for generating a display data signal, said display timing periods and said key scan timing periods appearing in a time sharing manner; key scan control means for receiving said display control signal and for outputting a key scan signal to scan said key matrix on the basis of said display control signal; selecting means for receiving and for selectively applying either one of said display data signal and said key scan signal to data transfer lines which operate as display data transfer lines when said selecting means outputs said display data signal and as key scan data transfer lines when said selecting means outputs said key scan signal, said display data transfer lines transferring display data to said display so that a character corresponding to said display data is displayed by said display and said key scan data transfer lines transferring key scan data to said key matrix such that operation of said display is interrupted; interrupt control means for generating and outputting a key scan interrupt request signal to the CPU in such a way as to be readable by the CPU; and key data hold means for receiving and holding key data output from the key matrix in synchronism with the key scan signal, for applying the held data to the CPU so as to be readable by the CPU, and for generating and sending a key scan inhibit signal to said display control means to inhibit a succeeding key scan operation until the held key data is read by the CPU.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-08-09 | 1997-02-08 | 1997-08-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-08-09 | 2001-02-08 | 2001-08-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-08-09 | 2005-02-08 | 2005-08-10 | $7700.00 | Window Closed / Lapsed |