JPS61151692A - Cursor display system for display unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cursor display method in a display device such as a cathode ray tube (CRT) display device.

BACKGROUND TECHNOLOGY] As is well known, in a CRT display device, when displaying characters on a display screen, one
Write the character code of the displayed character to the address corresponding to its display position in the refresh memory that has the address corresponding to pair l, and use the address signal that specifies the character position in the row direction (vertical direction) and column direction (horizontal direction) to Reads the character code written in the refresh memory, inputs this character code to the character generator, reads the font data of the character stored in advance in this character generator, and converts this font data into a serial video signal. The brightness modulation signal is input as a brightness modulation signal to the display section.

In this case, character codes for the refresh memory are written in sequentially by a processor such as a computer using a microphone that controls the operation of the entire display device. The cursor symbol is configured to be displayed together with characters to indicate the current position or the next display position.

Incidentally, in a display device that displays such a cursor symbol together with characters, there are many cases where a series of data processing results or data transferred from the outside are continuously displayed at high speed as characters on the display section.

[Problems to be Solved by the Invention] However, in the past, even when characters are displayed continuously at high speed as described above, the cursor symbol is displayed while moving in synchronization with the character display. There was a problem in that the display was distracting and the display screen became difficult to see.

In particular, there is a problem with block cursor symbols in which the cursor symbol is displayed in such a way that the background color of the displayed character and the color of the character pattern are different from the other parts, which makes the screen very difficult to see. means to solve
Effect 1 The present invention aims to solve the above problems, and includes a monitoring means for monitoring the writing cycle of character codes to a memory that stores character codes, and when the writing cycle of character codes is shorter than a predetermined cycle, is designed to prohibit the display of cursor symbols.

〔Example〕

Hereinafter, the present invention will be explained in detail based on examples.

FIG. 1 is a block diagram showing an embodiment of the present invention, in which a refresh memory 1 has a memory address that corresponds one-to-one with the characters displayed on the display section 15 during one display frame period and is equal to the maximum number of display characters. Display section 1
When displaying characters at the display position yi in the row direction (vertical direction) and the display position Xi in the column direction (horizontal direction), this Yi
The character code of the address number display character indicated by +Xi is written. In this case, the refresh memory 1 is within the memory address space of the entire display device, where yi =
-p (k<p), xH=j-t (j<, t) is assigned the address range.

The refresh counter 3 counts clock signals synchronized with the rask scan and outputs address signals representing display positions of display characters in the display section 15 in the row and column directions. The address range that can be specified by this address signal output from the refresh counter 3 is the above address range yi=k-p, x
i=j%I-, and this address range is decoded by the decoder 3. Then, the signal resulting from the decoding is selected by the multiplexer 4 and input as a chip select signal to the refresh memory 1 in an effective display period excluding the horizontal scanning period and the vertical scanning period. As a result, the refresh memory 1 has the address range 3' i = k - p, X i
= j~? Each address is sequentially specified by the address signal from the refresh counter 2 inputted via the second multiplexer 5, and the character code is read or written at this address. .

The character code read from refresh memory 1 is input to the address input of character generator 6.

The character generator 6 is composed of a memory element such as a read-only memory or a random access memory, in which font data of displayable characters is stored in advance, and when a character code is input from the refresh memory 1, a character generator corresponding to this character code is Output font data. The font data output from the character generator 6 is converted into serial pixel data in a parallel/serial converter (P/5-C) 7 in data units for each horizontal scanning line, and then converted into serial pixel data by an OR gate 8. After calculating the logical sum with the display signal, the display unit 15
It is input as a brightness modulation signal.

Thereby, the character code previously stored in the refresh memory 1 is displayed at the display position of the display unit 15 corresponding to the storage address. At this time, the last display character or the next display character is displayed with a cursor symbol added to it.

On the other hand, when writing the character code, the processor 9, which serves as a means for writing character codes into the refresh memory 1, writes the character code to the address y1==k-p+x1=j-tp.
An address signal corresponding to the display position of the character is output within the range of , and is supplied to the address input of the refresh memory 1 via the multiplexer 5. The address signal at this time is decoded by the decoder 10 to become a chip select signal C8, which is supplied to the chip select input of the refresh memory 1 via the first multiplexer 4. The processor 9 outputs a character code write command signal MW in synchronization with the sending of the address signal, supplies it to the read/write control input of the refresh memory 1 via the third multiplexer 11, and also outputs the character code to be written. Supplied to the data input/output terminal of the refresh memory 1.

In FIG. 2(a), the address signal outputted by the processor 9,
The chip select signal output by the decoder 10 is shown in (b) of the same figure, the write command signal MW is shown in (c) of the same figure, and the output timing of the character code to be written is shown in (d) of the same figure.

Note that the multiplexers 4, 5, and 11 are switched to the processor 9 side during the horizontal retrace period and the vertical retrace period.

As a result, the character code output from the processor 9 is designated by the write address signal or written to the address of the fresh memory 1.

Then, it is read out by the address signal output from the refresh counter 2 within a new display frame period,
It is displayed as characters on the display section 15.

By the way, while the processor 9 is writing a character code, the chip select C8 signal output from the decoder 10 and the write command signal WW output from the processor 9 are ANDed by the AND gate 12. There is. Then, by the AND signal, IJ)
The IJ gable type multivibrator 13 is triggered.

The multi-bye break 13 has an unstable time Tm set to be slightly longer than the time corresponding to the maximum writing speed of the character code, and when triggered by the output signal of the AND gate 12, it maintains the "L" level for the time Tm. The output signal is supplied to AND gate 14. A serial signal C3L for displaying a cursor symbol is input to the AND gate 14, and when the output signal of the multivibrator 13 is at "H" level, this serial signal C8L is output as is.
The logical sum gate 8 calculates the logical sum of the display character and the serial signal, and outputs the result to the display section 15.

However, the output signal of the multivibrator 13 is "'L"
In the case of the level, the AND gate 14 does not output the serial signal C8L for displaying the cursor symbol.

Therefore, when the character code is written at a speed shorter than the unstable time Tm of the multivibrator 13, the output signal of the multivibrator 13 becomes "L" level continuously, and the serial signal C3L for displaying the cursor symbol is logic The output signal of the multi-by-break 13 is shown in Fig. 2 (e), the serial signal for displaying the cursor symbol is shown in Fig. The output signal of gate 14 is shown.

〔Effect of the invention〕

As described above, in the present invention, if the writing cycle of the character code becomes shorter than a predetermined value, the signal for displaying the cursor symbol is prohibited from being input to the logical sum circuit that calculates the logical sum with the signal for displaying characters. Therefore, the cursor symbol will not be displayed. As a result, it is possible to eliminate the difficulty in viewing the display screen.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a time chart of various signals in FIG. 1. 1. Refresh memory, 2. Refresh counter, 8. OR gate, 9. Processor, 13. Multivibrator, 14. AND gate. Applicant's agent Takahisa Kimura:'Tsr''-

Claims (1)

[Claims] It has a memory that stores the character code of the character to be displayed,
The character codes stored in this memory are sequentially read from the character code writing means, and font data corresponding to this character code is generated from the character generator, and this font data and the current position or the next display position of the displayed character are A logical sum with a cursor symbol display signal representing the character code is determined by a logical sum circuit, and the logical sum signal is inputted to a display section, and in a display device that displays a cursor symbol along with characters, the writing cycle of the character code by the writing means is monitored. 1. A cursor display method for a display device, characterized in that the cursor symbol is not displayed by providing a monitoring means for inhibiting the input of the cursor symbol display signal to the OR circuit if the writing cycle is within a predetermined value.