JPH02224583A - Screen display device - Google Patents

Abstract

PURPOSE:To apply on/off control to a composite video signal and an RGB signal separately by providing a display control circuit having an output control means and a display control register having an output control register controlling the output control means. CONSTITUTION:When a level 1 is inputted to a V flag area 61a of an output control register 61 via an input control circuit from an externally mounted controller, an output port of a video mixer 17 is set by an output control means 13a and a composite video signal is outputted. When a level 1 is inputted to a P flag area 61b, an RGB signal is outputted from a port output control circuit 19 by the means 13a. That is, the output of each signal is turned on or off depending on the operating state of a device outputting the composite video signal and the RGB signal. For example, after the composite video signal is outputted to a VTR, the RGB signal with other display content than that of the composite video signal is outputted to a finder screen of a camera of the VTR to attain different display to the VTR and the camera thereby extending the applications of the device.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a screen display device that displays characters and patterns such as channel numbers in broadcast images displayed on a display device such as a cathode ray tube. .

[Prior Art] FIG. 3 shows an example of the configuration of a conventional screen display device of this type. In FIG. 3, 1 is a display oscillation circuit to which the oscillation output of the π-type LC oscillation circuit 1a is supplied, and 2 is a timing generator that generates various timings using the signals oscillated by the display oscillation circuit 1.

3 inputs the output of this timing generator 2 and control data (commands and character codes for display on/off, etc.) inputted to each input terminal 38 to 3c from a microcomputer, etc. (not shown) for controlling this screen display device. 4 is a data control circuit, 5 is an address control circuit, 7 is a display data memory for storing control data;
Consists of AM. 8 is the 4th character pattern etc. to be displayed.
A display character memory that stores the font configuration shown in the figure.
Consists of ROM. 6 is a display control register that latches commands such as display control among the outputs of the input control circuit 3; 9 is a horizontal and vertical synchronizing signal of the image signal supplied to terminals 9a and 9b, or internally generated horizontal and vertical synchronizing signals; 11 is a display position detection circuit for detecting the display position of characters, patterns, etc. on the display device; 12 is the display data memory; A read address control circuit reads data of the character to be displayed from 7, and 13 is a display control circuit that controls the display of the output of the display character memory 8 in accordance with display commands from the display control register 6.
This screen display device is composed of the above circuits,
The output of the display control circuit 13 is supplied to the video mixer 17, and the output from the video mixer 17 is connected to the CVIDEO terminal 1.
A video signal is output via 7a. Further, from the display control circuit 13, R, G, B color signals, etc. are sent to terminals 13a to 1.
It is output via 3f. 10 is an H counter, 14 is a shift register, 15 is an oscillation circuit for generating a synchronizing signal to which the oscillation output of the oscillation element circuit 15a is supplied, 16 is a timing generator for generating a synchronizing signal, and 21 is a blinking circuit.

Next, the operation will be explained. The input control circuit 3 processes control data input from a microcomputer or the like through terminals 38 to 3c, causes a display control register 6 to latch commands such as display control, and displays character codes and the like as display contents. It is stored in the data memory 7. During display, the character code stored in the display data memory 7 accesses the display character memory 8 as output data, and the display character font output from the character memory 8 is input to the display control circuit 13. Here, one word of the display data memory 7 has (a+b) bits.

If the number of displayed characters is C, then the total number of characters is (a+b).C bits are used. On the other hand, display character memory 8
One font consists of (JIXm) bits,
It is assumed that the number of types exists for n characters.

Also, regarding the display timing, a synchronization signal from the image signal is input to the synchronization signal switching circuit 9, this synchronization signal is counted by the H counter 10, and the position of the displayed character is determined by the display position detection circuit 11 based on this count value. decide. The display control circuit 13 synchronizes the display character output with an external video signal, performs display control according to the contents of the display control register 6, generates a display signal, outputs this display signal, and supplies it to the video mixer 17. In addition to the above display signal, R,
RGB signals, which are G and B color signals, are generated based on the signals from the display control register 6, and the RGB signals are output from each port terminal 13a to 13c.

Note that the synchronizing signal generation oscillation circuit 15 has one oscillation element circuit 1.
5a, it is possible to generate a synchronization signal of the NTSC system or PAL system, and this switching is performed by the signal from the N/P terminal 15b, thereby outputting 4fsc or 2fsc oscillation, and the timing generator 16 for generating the synchronization signal outputs oscillation of 4fsc or 2fsc. Since a synchronizing signal is generated, display on the TV screen is possible even when there is no signal.

In addition, the video mixer 17 allows NTSC and P
It is possible to generate an AL type composite video signal and to superimpose it onto an external composite video signal. The composite video signal has character level (LECHA), external composite video input (CVIN), blanking level (LEBK),
Six signals, background carrier color signal input (R3IN), color burst input (CBIN), and sync tip level, are switched and outputted using an analog switch.

[Problem to be solved by the invention] The conventional screen display device is configured as described above, and the R
When a GB signal is output, a corresponding composite video signal is also output. For example, when controlling a VTR with a composite video signal and controlling the viewfinder screen of a VTR camera with an RGB signal, each output signal is output according to the content to be displayed. There are problems in that it is not possible to separately control devices for signals, and the uses of each of the signals are limited.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a screen display device that can separately control on and off the composite video signal and RGB signals.

[Means for Solving the Problem] In the screen display device according to the present invention, one display control circuit includes a video mixer that outputs a composite video signal and an 'RG
a port output control circuit for outputting the B signal, and output control means for separately turning on and off the composite video signal and the RGB signal, and the display control register controls the output control means. It has an output control register.

[Operation] The screen display device according to the present invention controls the output control means by the output control register of the display control register, and turns on the composite video signal output from the video mixer and the RGB signal output from the port output control circuit, respectively. ,
The signal is turned off and the composite video signal and RGB signal are individually output to the corresponding devices.

[Example] An example of the present invention will be described below with reference to FIGS. 1 and 2. Components that are the same as those in FIGS. 3 and 4 are designated by the same reference numerals, and their explanation will be omitted.

18 is a video mixer 1 that generates various internal video signals;
A video signal generating circuit 7 outputs the video signal generating circuit, and a port output control circuit 19 outputs the ROB signal output from the display control circuit or the data output from the display control register 6 from port output terminals 19a to 19f. Display control circuit 13
are a video mixer 17 and R that output a composite video signal.
It has an output control means 13a that controls the port output control circuit 19 that outputs the OB signal and separately turns on and off the composite video signal and the RGB signal. Furthermore, the display control register 6 has an output control register 61 that controls the output control means 13a. This output control register 61 includes a V flag area 61a that controls the output of the video mixer 17, and the port output control circuit 1.
9, and a data area 61c for outputting data to the port output control circuit 19.

In the above configuration, when ``1'' is input from the external control device to the V flag area 61a of the output control register 61 via the input control circuit 3, the output port (not shown) of the video mixer 17 is controlled by the output control means 13a. Open, CV
A composite video signal is output via the IDEO terminal 17a. Next, when 1'' is input to the P flag area 61b, the output control means 13a opens the output port (not shown) of the port output control circuit 19, and the port terminals 19a to 19
RGB signals are output via c. That is, the output of each of the above signals is turned on depending on the usage status of the device that outputs the composite video signal and RGB signal.

Can be turned off. For example, by outputting a composite video signal to a VTR and then outputting an RGB signal with different display contents to the viewfinder screen of the VTR's camera, it is possible to display different displays on the VTR and camera. Its uses are expanded.

[Effects of the Invention] As described above, according to the present invention, the screen display device is configured to control the video mixer that outputs the composite video signal and the port output control circuit that outputs the RGB signal, so that the screen display device can output the composite video signal and the port output control circuit that outputs the RGB signal. A display control circuit having an output control means for turning on and off the RGB signals separately, and a display register having an output control register for controlling the output control means are provided, so that the composite video signal and the ROB signal can be controlled separately. It can be turned on and off, and signals with contents depending on the equipment being used can be output individually, expanding the usage of the equipment.

[Brief explanation of the drawing]

1 and 2 are block diagrams and partial block diagrams of a screen display device according to an embodiment of the present invention, FIG. 3 is a block diagram of a conventional screen display device, and FIG. 4 shows the structure of displayed characters. It is a diagram. DESCRIPTION OF SYMBOLS 1... Display oscillation circuit, 2... Timing generator, 3... Input control circuit, 4... Data control circuit, 5... Address control circuit, 6... Display control register, 7... ...Display data memory, 8...Display character memory, 9...Synchronization signal switching circuit, 10...H
Counter, 11... Display detection circuit, 13... Display control circuit, 13a... Output control means, 17... Video mixer. 18... Video signal generation circuit, 19... Port output control circuit, 61... Output control register.

Claims (1)

[Claims] In a screen display device that displays characters, patterns, etc. on a display device such as a cathode ray tube, there is provided an oscillation circuit that generates signals that serve as a reference for various timings, and a system that generates various signals based on the oscillation signals of the oscillation circuit. a timing generator that generates a timing signal; an input control circuit that receives and processes a control signal from an external control circuit such as a microcomputer; and a synchronization signal switching circuit that inputs a synchronization signal for a video signal to be displayed on the display device; A display position detection circuit that counts this synchronization signal to detect the display position of the display device, and control data such as characters, pattern codes, blinking information, etc. that are processed by the input control circuit and are to be displayed on the display device. a display data memory for storing the above display contents; a display character memory for storing the font of the characters displayed as the display contents;
A video signal generation circuit that generates each internal video signal for setting the color of the display signal, and a video signal generation circuit that generates each internal video signal to set the color of the display signal, and each mode circuit that displays the display content at a predetermined position of the display device using the position detection signal from the display position detection circuit. a display control circuit that outputs a predetermined display signal and an RGB signal that is R, G, and B color signals, and a video mixer that outputs a composite video signal obtained by mixing the display signal from this display control circuit and the video signal. a display control register that holds data input from the external control circuit to the input control circuit; and a port output that outputs data from the display control register or RGB signals from the display control circuit from each port terminal. a control circuit, the display control circuit having an output control means for controlling the video mixer and the port output control circuit, respectively, and turning on and off the composite video signal and the RGB signal separately; The display control register is
A screen display device comprising an output control register for controlling the output control means.