JPS54109324A - Generating circuit for key scanning signal - Google Patents
Generating circuit for key scanning signalInfo
- Publication number
- JPS54109324A JPS54109324A JP1623978A JP1623978A JPS54109324A JP S54109324 A JPS54109324 A JP S54109324A JP 1623978 A JP1623978 A JP 1623978A JP 1623978 A JP1623978 A JP 1623978A JP S54109324 A JPS54109324 A JP S54109324A
- Authority
- JP
- Japan
- Prior art keywords
- signal
- key scanning
- address
- ram
- word
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Input From Keyboards Or The Like (AREA)
- Calculators And Similar Devices (AREA)
Abstract
PURPOSE: To improve the manufacture yield of a LSI with the circuit constitution simplified by providing a method which generates a key scanning signal regarding the address selective signal of RAMs arrayed in several digits and several lines as a fundamental signal.
CONSTITUTION: Terminals A to D are output terminals of an address counter and when the address line of one of AND circuits A0 to A8 becomes "1" by a signal counted up at every one-word time, four cells of the RAM connected to the line is selected, so that memory contents of the RAM will be outputted via output lines Q1 to Q4. Output terminals of circuits A0 to A8 are connected to output buffers B0 to B8 respectively, which are connected to outputs K0 to K8 by way of two inverters. When a signal according to the word time is inputted to inputs A to D, key scanning signals which become "1" in the word-time order of (a) to (i) are outputted to outputs K0 to K8. RAM address assignment signals can therefore be assigned as key scanning signals not by providing a special digit-signal generating circuit and, consequently, the circuit constitution can be simplified.
COPYRIGHT: (C)1979,JPO&Japio
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP1623978A JPS54109324A (en) | 1978-02-15 | 1978-02-15 | Generating circuit for key scanning signal |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP1623978A JPS54109324A (en) | 1978-02-15 | 1978-02-15 | Generating circuit for key scanning signal |
Publications (1)
Publication Number | Publication Date |
---|---|
JPS54109324A true JPS54109324A (en) | 1979-08-27 |
Family
ID=11910998
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP1623978A Pending JPS54109324A (en) | 1978-02-15 | 1978-02-15 | Generating circuit for key scanning signal |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS54109324A (en) |
-
1978
- 1978-02-15 JP JP1623978A patent/JPS54109324A/en active Pending
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