JPS589449B2 - CRT display device with light pen - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a CRT display device equipped with a light pen, and particularly to a CRT display device with expanded functions of a light pen.

In the past, light pens were generally used for pointing to selectively indicate coordinates on a CRT screen and transmit them to a computer, but recently they have been used for drawing when creating a screen on a CRT. There is a tendency.

However, because the functions required for voicing and drawing are different, each requires a unique hardware configuration.

FIG. 1 shows a conventional example of pointing.

FIG. 2 shows a conventional example for use in drawing.

The configuration of FIG. 1 includes a computer 1, an interface circuit 11
, timing generation circuit 12, screen information memory (refresh memory) 13, pattern generator (character pixel generation circuit) 14, color bling control circuit 15, and gate 1
6, 17, 18, 22, 30, buffers 19, 20, OR gates 21, 29, position detection line generation circuit 23.
CTR 24, light pen 25, light pen switch control circuit 26, photodetection signal waveform shaping circuit 27, line display period storage flip-flop 28, interrupt signal storage flip-flop 31. It consists of a counter 32 for light pen indicated coordinates.

In FIG. 1, data written from a computer to a CRT display device is stored in a refresh memory 13 through an interface circuit 11.

The data stored in the memory 13 is sequentially read out by a continuously changing address signal from the timing generation circuit 12, and then passed through the character/pixel generation circuit 14 and the color pulling control circuit 15, and is then read out as red (R) and green (G). , blue (B), and sent to the CRT 24.

By operating the switch on the CRT screen, the light pen 25 is separated into a signal 26a when the switch is ON and a signal 26b when it is OFF by the light pen switch control circuit 26, and the flip-flop 28 is set by the signal when the switch is ON. do.

As a result, the AND condition of the gate 22 is established, and the output of the position detection line generation circuit 23 is passed through the OR gate 21.
It is sent to the viewer 24 as a green signal.

As a result, a blue line is scanned on the tube surface, superimposed on the previously shown image.

When the light pen detects light by scanning this evening line, it is sent to the waveform shaping circuit 27 as a position detection signal, and this output passes through the OR gate 29 to the flip-flop 2.
8 is reset, the AND of the gate 22 is not established, and the display of the position detection line is erased.

When the position detection line is displayed, the light pen 25
If the position cannot be detected, turn the light pen switch ON.
The F signal 26b resets the flip-flop 28 and erases the line display.

On the other hand, by ANDing the switch signal and the position detection signal, the interrupt flip-flop 31 is set and the computer is notified of the interrupt.

At the same time, the light pen counter 32 is stopped to prepare for reading the indicated coordinates from the computer.

Figure 2 shows a typical circuit configuration when using a light pen for drawing purposes. , is transmitted to the CRT 24.

The circuit 40 is a circuit that determines the display coordinate position of the marker based on the output of the light pen counter 32 and the output from the timing circuit 12.

Next, if the line generation circuit 23 for position detection always displays lines during drawing, control by the gate 22 as shown in FIG. 1 is not necessary.

Regarding interrupts to computers, in many cases, an interrupt signal is generated only when a defined specific area on the screen is specified. Interrupt flip-flop 31 is set.

In such a case, control data for displaying data such as color and shape, entry data for indicating a drawing location, interrupt instructions, and position detection lines are displayed on the CRT screen.

The difference in structure between the two cases of H-pointing and drawing arises from the difference in functional requirements between the two.

Putting these together, we get the following.

First of all, there are three basic functions of light pens in general:

(a) There is a position detection line necessary for Light Ben to operate.

(b) Be able to correctly indicate the planned coordinates on the screen.

(c) Generating an interrupt signal to a computer by operating a light pen.

However, there is a big difference in the specific requirements for each of the above functions when using a light pen for the purpose of pointing (indicating coordinates) and when using it for drawing.

When the purpose is to indicate coordinates, (a) If the position detection line appears on the screen when the screen is activated, the actual screen and life overlap, making the screen difficult to see.

Therefore, the position detection line scans the screen only at the moment when the operation switch of the light pen is operated.

(b) In the case of method (a) above, the position cannot be detected until the light pen switch is operated, so it is not possible to confirm the correctness of the indicated position in advance.

Therefore, it is often the case that adjacent position coordinates are erroneously designated, and it is necessary to create a space between the designated positions or to provide software to invalidate erroneous inputs.

(c) Since the purpose is to inform the computer of the specified position by specifying the coordinates, it is necessary to generate an interrupt signal to the computer at the same time as the light pen switch is operated.

In response to the above-mentioned requirements for the light pen function for coordinate indication applications, by writing the characters and pixels specified by the light pen at the cursor position, etc., and repeating such operations, the screen can be displayed on the CRT screen. When using a light pen for drawing.

(a) Coordinate display for position recognition is required on the screen for drawing, but the position detection line can be used as a substitute for this purpose.

Furthermore, since the light pen is frequently used during drawing, it is easier to use it for drawing when the position detection line is always displayed rather than appearing and disappearing.

(b) If the position detection line is always displayed as in (a) above, the position can be detected simply by bringing the light pen close to the CRT screen, so this position can be displayed as a marker. .

Therefore, the operator can confirm the correctness of the indicated position before operating the light pen switch.

(c) In the case of drawing, the drawing is done in units of characters or in groups by operating the light pen switch, so there is no need to interrupt the computer each time, and the computer is sent to the computer after completing the specified drawing. An interrupt will be issued and the drawing data will be read.

Therefore, it is inconvenient to generate an interrupt signal every time a switch is operated, as in the case of coordinate indication use.

As mentioned above, the fundamental requirements for the light ben function are contradictory in cases where the purpose is to indicate coordinates and when it is used for the purpose of drawing, so if one function is emphasized, it will be very difficult to use the other purpose. The user is forced to use a light pen function that is difficult to use.

Furthermore, depending on the user's purpose, it may be necessary to change the light pen function each time.

An object of the present invention is to eliminate the drawbacks of the above-mentioned conventional examples, and to provide an extremely flexible C with a light pen.
The present invention provides an R'T display device.

The gist of the present invention is to use a computer to set control data for instructing whether to point or draw, thereby distinguishing between pointing and drawing and allowing them to be performed efficiently.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 3 shows an embodiment according to the invention.

In this embodiment, in order to control the display of the light pen marker, the display of the position detection line, the interrupt signal to the computer, etc., flip-flops 50, 51, which can arbitrarily set control data according to instructions from the computer, are used. 52.

When the flip-flop 50 is in the set state, the light pen marker output of the circuit 40 passes through the AND gate 53 and is displayed on the CRT24 via the OR gate 43, but when the flip-flop 50 is in the reset state, , gate 53 inhibits the output signal from circuit 40.

In the case of position detection line display, the output of the position detection line generation circuit 23 is sent to AND gates 54 and 55.

When the flip-flop 51 is in the set state, the detection line passes through the gate 54, passes through the OR gates 56 and 21, and is displayed on the CRT 24.

In this case, the presence or absence of the output from the gate 55 has no relation to the output from the gate 56 because the output from the gate 54 is always output.

When the output of flip-flop 51 is in the reset state, the output of line generation circuit 23 cannot pass through AND gate 54.

Therefore, the output of the line generation circuit 23 is controlled by the output of the circuit block 33, and passes through the AND gate 55 only while the output of the circuit block 33 is valid.
6, 21 and displayed on the CRT 24.

The operation of the circuit 33 is the same as that described in FIG. 1, and only the instant of light pen operation is displayed.

By controlling the state of the flip-flop 51 from the computer in this way, it becomes possible to control the position detection line in a way that suits the application.

Next, the light detection signal from the light pen 25 is directly sent to the light pen coordinate counter 32 via the waveform shaping circuit 27, as in FIG. 2, and the counter is stopped at the coordinate detection position.

In other words, when the detection line is always displayed and the light pen can be detected, the contents of the counter 32 change regardless of the switch operation of the light pen (the counter 32 receives the vertical synchronization signal from the timing circuit 12). Automatically starts Kawanta, and stops when a light detection signal is received.

That is, when the light pen is moved, the contents of the counter change to new coordinates every time one frame of the CRT screen is scanned.

) Therefore, the output of this counter 32 is sent to the light pen marker generation circuit 40, making it possible to display a marker at the position indicated by the light pen.

Regarding the interrupt signal to the computer, the signal when the light penno switch is operated is sent to the AND gate 57 through the switch signal control circuit 26, controlled by the output of the flip-flop 52, and sent to the interrupt flip-flop 31. Set.

That is, by recognizing the purpose of use of the light pen on the computer side and controlling the flip-flops 50, 51, and 52,
It is possible to use the light pen in a way that is most suitable for the purpose.

In the above embodiment, three types of control data are shown, and one of them can be displayed by the CRT display device.
Alternatively, three or more pieces of data may be required.

In such a case, flip-flops will be provided depending on the amount of data.

The control data may be set using computer software or may be set manually through a console.

According to the present invention described above, it is no longer necessary to divide functions based on unique hardware between pointing and drawing, or to consider special usage during use.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration during conventional pointing, FIG. 2 is a diagram showing the configuration during conventional drawing, and FIG. 3 is a diagram showing an embodiment of the present invention. 1... Computer, 24... CRT, 50, 51, 52...
Flip flop.

Claims (1)

[Claims] I CRT and a second IAND gate connected in parallel to the line scanning signal for position detection displayed on the CRT screen.
a position detection line generation circuit that outputs an output via an AND gate; a light pen that indicates a position on a CRT screen, detects the position detection line scanned to the position, and outputs a position detection signal; a light pen counter that stops a count that is started in synchronization with the position detection line scan in response to the position detection signal and detects the indicated coordinate position based on the count value; and a light pen counter that detects the indicated coordinate position based on the count value; The display coordinate position signal of the marker is sent to the 3rd AN.
a light pen marker generation circuit that outputs to the CRT via a D gate, an operation switch provided on the light pen, and a computer that selectively outputs each control data for drawing, pointing, and interrupt; The first and third AND gates are opened by the drawing control data and closed by the pointing control data, and the second AND gate is opened when the operation switch is turned on and is opened by the position detection signal. A CRT display device comprising a light pen configured to be closed and to issue an interrupt command to the computer when the interrupt control data and the operation switch are turned on.