JPS62235629A - Light pen control circuit - Google Patents

Abstract

PURPOSE:To improve operativity by holding the brightness of display information for light pen detection constant on a display picture regardless of the brightness of other video signals. CONSTITUTION:A light pen control circuit consists of a CRT control circuit 1, a multiplexing circuit 2, a memory circuit 3, a video composing circuit 11 including resistances 5-6, a transistor (TR) 7, and diodes 8-9, and a gate circuit 12 corresponding to a light pen and a display 10. When light pen attribute data 106 are inputted through a gate circuit 12, the data are inputted to the display 10 through the TR 7 and diode 8 in this video composing circuit 11. If the data 106 are effective and a video signal 108 is also effective, light pen detection display information can be displayed on the display 10 and its brightness is held high regardless of the video signal 108 so that it is easily detected.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to light pen control circuits.

[Conventional technology]

Conventionally, this type of light pen control circuit has no H.

The display of Atribi Island-F for light pen detection is generally performed by brightening the entire display screen when the light pen is pressed, or by keeping the display screen bright all the time. .

[Problem that the invention seeks to solve]

Regarding the conventional light pen control circuit described above.

The display of light pen attribute data for light pen detection is displayed on the entire screen 1 when the light pen is pressed:
Since the display screen is made brighter and the display screen is kept brighter all the time, there are disadvantages in that it gives a visual discomfort to the operator and also causes problems in operability.

〔problem? Means to solve]

The two-event system #11j circuit of the present invention has a predetermined C14T
A control circuit that generates a horizontal drive signal for the display device, a vertical drive signal, and a display address information sound, and the display address information and write address information sent from a higher-level device are inputted and sent from a higher-level device. related to the validity of the light select signal that is generated.

a multiplexer circuit that outputs one of the address information -f'', and when the write address information is valid, predetermined memory write data is written, and during the display period of 16 on the CRT display device, the memory write data is A memory circuit is read out and output as light pen attribute data, and a
FIG. 1 is a block diagram showing an embodiment of the present invention. One embodiment, as shown in FIG.
and corresponding to display 10.

A C-T control circuit 1 and a multiplex circuit 2.

Memo +7 circuit 3, resistor 5z and 6. transistor 7,
It includes a video synthesis circuit 11 including diodes 8 and 9'lt, and a gate circuit 12.

3 in FIG. 1, a horizontal drive signal 101 necessary for driving the display 1Oyr is output from the CRT control circuit 1.
jd and vertical drive signal 102 are output and sent to the display 10, respectively, and display address information 103 necessary for one display is output and sent to the multiplex circuit 2. Write address information 104s and a predetermined write select signal 109 given from the higher order are also input to the multiplex circuit 2 through terminals 51jd and 52, respectively.
Under the control, either the display address information 103g or the write address information 104 is switched and output and inputted to the memory circuit 3. In this case, one display address information 103 is input to the memory circuit 3 during one display period, and write address information 104 is input to the memory circuit 3 during a period in which the write select signal 109 is valid.

On the other hand, from the terminal 53, memory write data 1 from the higher order
05 is not sent to the memory circuit 3, and when writing this memory write data 1osv to the memory circuit 3, write select signal 109'! By enabling i and providing the write address information 104ya/, the memory write data 1o5 is written to the target location of the circuit 3 indicated by the write address 104. The memory write data 105 written in the memory circuit 3 is stored in S during the display period.
It is read out periodically according to the display address information 103 inputted from the C-T control circuit 1, and sent to the gate circuit 12 as light pen attribute data 106.

The light ben strobe signal 107 is output from the light ben 4 and input to the gate circuit 12.

This is a signal that is valid only while the light ben 4 is pressed down, and the input it+-^rai Eben attribute data 106 is input to the gate circuit 12 via the gate circuit 12' only while the light ben 4 is being pressed down. The signal is input to the video synthesis circuit 11. In the video synthesis circuit 11 2, when the light pen attribute data 106 is inputted via the gate circuit 12'Y, the transistor 7 is activated.

Light Venn attribute data is input to a display 10 through a diode 8. This light vent attribute data 106 is valid.

In addition, when the video signal 108 input to the terminal 54 is also valid, the voltage dividing points of the resistors 58 and 6 are selected so that the potential on the anode side of the diode 8 is higher than the potential on the anode side of the diode 9. By doing this, when the V% light pen attribute data 106 is valid, it becomes possible to display the display information for light pen detection on the display 10, regardless of the video signal lO8 inputted from the terminal 54. It becomes possible to fix the brightness to a constant level. 8. By appropriately selecting the voltage dividing voltage using the resistors 5s and 6 in accordance with the DC voltage supplied from the terminal 55, high brightness that can be easily detected by the light ben 4 can be easily obtained. Also.

The light pen attribute data 106 is displayed only when the light pen 4 is pressed, and in places where the light pen detection display information is not displayed.

Maintains normal brightness.

〔Effect of the invention〕

As explained above, the present invention improves the performance ability of a light pen by keeping the brightness on the display screen of display information for light pen detection at a constant high brightness regardless of the brightness of other video signals. This has the effect of eliminating discomfort for the operator and improving operability without degrading the performance.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the main parts of an embodiment of the present invention. In the figure, 1...CT control circuit, 2...
...Multiplex circuit, 3...Memory circuit, 4...Light pen, 5, 6...Resistor, 7...Transistor. 8.9...diode, 10...display. 11...Video synthesis circuit, 12...Gate circuit. 7.-One agent, patent attorney, Susumu Uchihara. Shizu 2. ,7'

Claims (1)

Claims: A horizontal drive signal for a given CRT display. CRT that generates vertical drive signals and display address information
a control circuit, and a multiplexer that inputs the display address information and write address information sent from the upper layer, and outputs either one of the address information in relation to the validity of the write select signal sent from the higher layer. circuit and
a memory circuit in which predetermined memory write data is written when the write address information is valid, and in which the memory write data is read out and output as light pen attribute data during a display period on the CRT display device; A light pen control circuit comprising: a video synthesis circuit that synthesizes the light pen attribute data inputted when a light pen strobe signal outputted from the light pen strobe signal is valid and a predetermined video signal.