JPS5926425Y2 - light pen control circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a light pen control circuit that corrects and outputs an address detected by a light pen according to horizontal or vertical writing of the display format of a display device.

As shown in FIG. 1, the display format of a conventional Japanese character display device is such that the character area 11 on the display screen 10 has a size of, for example, 32 x 32 bits, and 32 characters per line are written horizontally in the X direction. 21 vertical lines are displayed in the Y direction via the line spacing section 12.

The addresses on the display screen of each character area are horizontal direction XAD addresses 20 to 31, vertical direction YAD=
They are indicated by addresses O-20, and the count values of the address counters of the pattern memory are assigned O-31 and 0-20, respectively.

When using a light pen on such a display screen, the detected image 13 is applied to the desired character and the corresponding digit is displayed.
Evening is read out.

However, when using a cathode ray tube (CRT), there is usually a delay in the light emission of this phosphor screen, so the detection is equivalent to, for example, if a character in the diagram is selected but the light is emitted at a position three addresses later than that. I get a signal.

This situation is shown in Figure 3a. On the other hand, recently, Japanese character display devices are sometimes required to have a vertical display format.

In this display format, as shown in FIG. 2, 32 character areas 11 are consecutively arranged in the Y direction, and 21 lines are displayed from right to left with interline margins 12 interposed in the X direction.

In other words, the addresses on the display screen in this case are vertical direction Y'AD=0~31, horizontal direction X'AD=0~
It will be number 20.

On the other hand, the display speed is constant regardless of whether it is written horizontally or vertically, and therefore the delay time when detecting the detected image 13 is the same.

The number of bits that constitute one character is 32 x 32 bits regardless of whether it is written horizontally or vertically.

On the other hand, in the case of horizontal writing, the characters are continuous in the X direction, and the margins 12 between the lines are in the Y direction, and in the case of vertical writing, the characters are continuous in the Y direction, and the margins 12 between the lines are in the Y direction. 12 is X
direction.

Therefore, since the position of the margin 12 between the lines is different between horizontal writing and vertical writing, it is not possible to use one format, for example, an address for horizontal writing as an address for vertical writing.

An object of the present invention is to provide a light pen control circuit that corrects and outputs an address detected by a light pen according to horizontal or vertical writing of the display format of a display device.

In order to achieve the above object, the light pen control circuit of the present invention includes means for switching the display format of the indicating device between horizontal writing and vertical writing, a light pen for detecting desired display data on the display screen, and a light pen for detecting desired display data on the display screen. Depending on whether the address detected by the light pen is written vertically or horizontally, the number of bits in one character,
The present invention is characterized in that it includes a circuit that outputs an address corrected by a correction value determined by the number of bits in the space between lines and the delay of the light pen detection signal.

The present invention will be described in detail below with reference to examples.

As mentioned above, horizontal writing and vertical writing differ in the direction in which the margins 12 between the lines exist, as can be seen by comparing FIGS. 1 and 2.

In other words, in the case of horizontal writing, there is a margin 12 between lines in the Y direction.
exists, and in the case of vertical writing, there is a margin 12 between lines in the X direction.
exists.

Therefore, when the detected image 13 of the light pen is given, in the case of horizontal writing, as shown in FIG.
Assuming that the position of "N" is detected due to the time delay when "N" is displayed, the memory address "5°" corresponding to "N" is detected.
The corrected address is "2" which is subtracted from "2" by 3.

On the other hand, in the case of vertical writing, as shown in the same figure,
For example, the “display screen” corresponding to memory address “3”
Since the time delay when the detected image 13 is displayed is the same as horizontal writing, the position of the "kanji printer" is detected.

Therefore, the corrected memory address is "1" plus 2, or 3, which corresponds to "Kanji Printer".

Therefore, in order to enable both horizontal writing and vertical writing, a means for switching between the two is provided, and in the case of horizontal writing, for example, a predetermined number is added or subtracted from the detection address of the detected image.
In the case of vertical writing, correct memory addresses can be obtained by providing a circuit that adds and subtracts a predetermined number different from that in the case of horizontal writing.

FIG. 4 is an explanatory diagram showing the configuration of an embodiment of the present invention based on the above-mentioned principle.

In the figure, the horizontal and vertical coordinates of the scanning signal for the character area on the display screen are XAD when written horizontally.

It is assumed that X'AD and Y'AD are respectively input to registers 24 and 25, and when vertical writing is performed, the switch is made such that X'AD and Y'AD are respectively input to registers 25 and 24.

Sampling is performed by inverting and applying the light pen detection signal to the registers 24 and 25 in parallel by the inverter 21.

However, if the coordinate data is output as it is, the data will be incorrect due to the delay in the light pen detection signal mentioned above, and this must be corrected.

Therefore, when writing horizontally, for example -
A 3rd address subtraction signal is applied by the 3rd generation circuit 22 to perform correction.

When writing vertically, a 2nd address addition signal is applied to the register 25 from, for example, the +22 generation path 23 to perform correction.

By sending the thus corrected sampling signal to the pattern memory and detecting a match, it is possible to obtain a correct plugging pattern.

In this manner, in horizontal writing and vertical writing, the registers 24 and 25 for inputting horizontal and vertical scanning signals are switched, and address correction is performed for the register on the horizontal side.

The sign of this correction value is generated by right-to-left writing and left-to-right writing, and the value differs depending on whether there is a blank space between lines in the scanning direction.

In this way, in the example, we assumed -3 for horizontal writing and +2 for vertical writing, but this value is the number of bits of one character,
It is set to various values depending on the number of bits in the space between lines and the delay of the light pen detection signal.

As explained above, according to the present invention, horizontal writing and vertical writing are switched, and only the address corresponding to vertical writing or horizontal writing is added or subtracted from the address detected by the light pen, and the result is output as a memory address. Therefore, it is possible to apply a light pen to this in the same way by sharing horizontal writing and vertical writing, and based on the same idea, the present invention can be applied to switching between various formats. It becomes possible.

[Brief explanation of drawings]

Figures 1 and 2 are general illustrations of horizontal and vertical writing, Figure 3a and 1) are illustrations of the principle of the invention, and Figure 4 shows the configuration of the main parts of the embodiment of the invention. It is an explanatory diagram, and in the diagram, 1
0 is the display screen, 11 is the character area, 12 is the line spacing, 1
3 is an image to be detected, 21 is an inverter, 22 is a -3 generation circuit, 23 is a +22 generation path, and 24.25 is a register.

Claims (1)

[Scope of utility model registration request] A means for switching the display format of a display device between horizontal writing and vertical writing, a light pen for detecting desired display data on a display screen, and an address detected by the light pen depending on whether it is written vertically or horizontally. A light pen control circuit comprising: a circuit for outputting an address corrected by a correction value determined by the number of bits of one character, the number of bits of a line spacing, and a delay of a light pen detection signal.