Digital pattern display system

• US 4,215,343 A
• Filed: 02/16/1979
• Issued: 07/29/1980
• Est. Priority Date: 02/16/1979
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Ueda, Hirotada, Ejiri, Masakazu
• Primary Examiner(s): Trafton, David L.
• Application Number:
  US06/012,800
• Time in Patent Office: 529 Days
• Field of Search: 340/711, 340/724, 340/727, 340/751, 340/747, 340/750, 84/DIG. 6
• US Class Current: 345/27
• CPC Class Codes: G09G 1/00 Control arrangements or circuits, of interest only in connection with cathode-ray tube indicators; General aspects or details, e.g. selection emphasis on particular characters, dashed line or dotted line generation; Preprocessing of datacathode-ray oscilloscopes G01R13/20; radar display arrangements G01S7/04; display of digital non-picture data in television systems H04N7/0255
• CPC Class Codes: G09G 5/42 characterised by the display of patterns using a display memory without fixed position correspondence between the display memory contents and the display position on the screen
• CPC Class Codes: Y10S 84/06 Cathode-ray tube

Abstract

A pattern display system is disclosed which includes a keyboard for the manual entry of data representative of the patterns to be displayed, a microcomputer for accepting the entry data and for controlling the display system, a random access memory for storage of the entered data, audio circuitry controlled by the microcomputer for accepting data to provide audio signals representative of stored data, coding/decoding circuitry for the transfer of stored digital data to or from a tape recorder, and video circuitry utilized under the control of the microcomputer for the visual display on a cathode ray tube (CRT) of the patterns represented by the stored data. Specifically, the video circuitry includes read-only memories which are controlled to provide video pattern information in response to the stored data which represented desired patterns and timing information for the CRT.

Claims

1. A pattern display system for use with a cathode ray tube, comprising:

a keyboard having selectively actuable key switches, each of said switches representing a predetermined symbol or function;

processing means responsive to said keyboard switches for storing information representative of symbols corresponding to the symbols represented by actuated symbol key switches, and for performing predetermined functions corresponding to functions represented by actuated function key switches, said processing means further providing as an output pattern display information representative of the individual patterns necessary for the display of said symbols; and

video circuitry responsive to said processing means for generating video signals indicative of the patterns represented by said pattern display information, said video circuitry including first and second read-only memories which are accessed as a function of said pattern display information and the vertical scan of the cathode ray tube, said second read-only memory containing display information for each horizontal line segment of all patterns utilized by the pattern display system and said first read-only memory controlling said second read-only memory.

2. The pattern display system of claim 1 wherein said video circuitry includes a first recirculating shift register for storing display pattern codes and a second recirculating shift register for storing display vertical position codes associated with said pattern codes, each pattern code having a corresponding vertical position code, and said shift registers providing respective individual pattern codes and position codes as outputs.

3. The pattern display system of claim 2 wherein said first read-only memory is addressed as a function of the output of said position code shift register and the vertical scan of the cathode ray tube, and wherein said second read-only memory is addressed as a function of the output of said pattern code shift register, the output of said first read-only memory, and the vertical scan of the cathode ray tube.

4. The pattern display system of claim 3 wherein said shift registers are simultaneously shifted as a function of the horizontal scan of the cathode ray tube.

5. The pattern display system of claim 4 further including an X-counter for controlling the horizontal scan of the cathode ray tube, and a Y-counter for controlling the vertical scan of the cathode ray tube.

6. The pattern display system of claim 5 wherein said first read-only memory is partially addressed by preselected bits of said Y-counter, and wherein said second read-only memory is partially addressed by different preselected bits of said Y-counter.

7. The pattern display system of claim 6 wherein said shift registers are shifted as a function of said X-counter.

8. The pattern display system of claim 2 wherein the correspondence between the pattern codes and the position codes in said respective recirculating shift registers is determined by position within said respective recirculating shift registers.

9. The pattern display system of claim 8 wherein respective display horizontal positions of patterns represented by said pattern codes is determined by the respective positions of said pattern codes within the first recirculating shift register.

10. A display system for use with a cathode ray tube for displaying a plurality of individual display patterns wherein each display pattern is defined by selectively illuminated binary display dots which are vertically arranged in horizontal line segments, the combination comprising:

means for storing pattern codes representative of each display pattern to be displayed and for providing as its output individual pattern codes indicative of the display patterns to be displayed, said pattern code storing means being accessed as a function of the cathode ray tube horizontal scan to provide said output pattern codes at the proper time for display, and each of said pattern codes having a reference pattern comprised of a matrix of binary display dots which is subdivided into subregions, each subregion having adjacent horizontal line segments of binary dots;

means for storing a vertical position code for each of said pattern codes and for providing as its output the position code associated with the pattern code output of said pattern code storing means, each of said position codes being indicative of the vertical display position of the display pattern represented by the associated pattern code, said vertical position code storing means being accessed as a function of the cathode ray tube horizontal scan to provide the proper position code output for the pattern code output of said pattern code storing means;

first memory means addressed as a function of said position code output and the cathode ray tube vertical scan position for providing as its outputs information indicative of whether a component of a display pattern is to be displayed at the present scan of the CRT and which subregion of the reference pattern corresponding to the output pattern code is presently to be displayed; and

second memory means addressed as a function of said pattern code output, said first memory means output, and the vertical scan position of the cathode ray tube, said second memory means providing an output representative of the present line segment of a display pattern to be displayed.

11. The display system of claim 10 further including an X-counter for controlling the horizontal scan of the cathode ray tube, and a Y-counter for controlling the vertical scan of the cathode ray tube.

12. The display system of claim 11 wherein said pattern code storing means comprises a recirculating shift register, and wherein said position code storing means comprises a recirculating shift register, said shift registers being shifted as a function of said X-counter.

13. The display system of claim 12 wherein said first memory means is addressed in part by a first portion of the contents of said Y-counter, and wherein said second memory means is addressed in part by a second portion of the contents of said Y-counter.

14. The display system of claim 13 wherein said first and second memory means each comprises a read-only memory.

15. The display system of claim 14 wherein said first read-only memory defines the sequence in which the subregions of the reference pattern corresponding to the pattern code output are to be displayed, thereby providing for the display of display patterns different from the reference patterns associated with said pattern codes.