JPH02296293A - Screen display device - Google Patents

Abstract

PURPOSE:To make the trimming of basic data equal to that of reversal data and to reduce a number of select circuits for a selective circuit by providing the selective circuit, which existed between a character storage circuit and a shift register, after a trimming generation circuit. CONSTITUTION:The selective circuit 3 which existed between the character storage circuit 1 and the shift register 4 is provided after the trimming generation circuit 5. Therefore, after the trimming data is generated, pattern data is reversed or not reversed. Thus, the trimming of the basic data is made to be equal to that of the reversal data, and also the number of the select circuits is reduced because serial pattern data is input to the selective circuit 3 instead of the parallel pattern data being input to the selective circuit 3.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to an improvement in a screen display device for displaying characters on a screen such as a TV, and particularly relates to the inverted output of a character and the border of the inverted output of a character. be.

[Conventional technology]

FIG. 3 is a block diagram showing a conventional screen display device. In the figure, 1 is a character memory circuit that stores character pattern data, and 2 is a character memory circuit that stores data specifying arbitrary pattern data of the character memory circuit 1. a display memory circuit; 3 is a character memory circuit; a selection circuit that inverts or non-inverts the output data from the display memory circuit; 4 is a shift register that converts the parallel output output from the selection circuit 3 into a serial output; 5 Reference numeral denotes an edge generation circuit that generates edge data, 6 a display output circuit that outputs to a display, and 10 a display.

FIG. 4 is a circuit diagram showing the configuration of the selection circuit 3 of FIG. 3. In the figure, 7a to 7f are first inverter circuits, 8 is a second inverter circuit, and 9a to 9f are select circuits. FIG. 5 is a circuit diagram showing the configuration of the border generation circuit 5 shown in FIG. 3, and FIG.
) Figure shows the basic data, (Figure b1 shows the basic data with a border added, Figure (c) shows the inverted display, and (D1 figure shows the case where the inverted data has a border added.

Next, the operation will be explained. The data stored in the display memory circuit 2 is output to the character memory circuit in order. At this time, the stored data specifies pattern data stored in the character storage circuit 1. The designated pattern data is output to the selection circuit 3 and output to the shift register 4 after being inverted or non-inverted depending on the data separately output from the 1-display storage circuit 2. To explain the operation at this time with reference to FIG. 4, if the pattern data output from the character storage circuit l is N bits, the pattern data N bits input from the N select circuits 98 to 9fIζ are transferred to the first inverter circuit. The remaining output of the display storage circuit 2 is used to select whether to output through or without passing through the signal. The shift register 4 converts the received parallel pattern data into serial pattern data and outputs it to the edge generation circuit 5. The border generation circuit 5 outputs the border data and serial pattern data to the display output circuit 6, and the display output circuit 6 synthesizes the pattern data and border data and outputs the synthesized data to the display device 10i. Here, generation of border data will be explained using the border generation circuit 5 shown in FIG. 5. It is input to the serial pattern data connected to three stages of D-FF and shifted using the CK clock. The border data is ORed through an OR circuit before and after the pattern data is output, and when the pattern data is output, it is output through the melon circuit in order not to generate border data.

However, if the pattern data is inverted by the selection circuit 3,
Fig. 6 (b) Framing with basic data shown as a>
and the 6th border with inverted data shown in Figure 6 (eHζ)
This results in a different border from that shown in Figure (d).

[Problem to be solved by the invention]

Since the conventional screen display device had the IC configuration as described above, different edge data would be generated depending on the border of the basic data and the border of the inverted data, and the selection circuit would not be able to handle the data entering the shift register. There were problems such as the need for select circuits equal to the number of select circuits.

This invention was made in order to solve the above-mentioned problems, and provides a screen display device in which the borders of basic data and inverted data can be made the same, and the number of select circuits can be reduced. The purpose is to

[Means to solve the problem]

In the screen display device according to the present invention, the selection circuit that was between the character storage circuit and the shift register is provided after the border generation circuit, thereby significantly reducing the number of selection circuits.

[Operation] The selection circuit in this invention is provided after the edge generation circuit, and after generating edge data, inverts or non-inverts the pattern data, so that the edge in the basic data and the edge in the inverted data are made the same. In addition to inputting parallel pattern data into the selection circuit, serial pattern data is input into the selection circuit, so the number of selection circuits can be reduced.
When using C, the chip area can be reduced.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a screen display device according to an embodiment of the present invention. In the figure, 1 is a character storage circuit that stores character pattern data, and 2 designates arbitrary pattern data in the character storage circuit 1. 3 is a selection circuit that inverts or non-inverts the character pattern data from the border generation circuit with the data from the display storage circuit; A shift register converts the output into a serial output, 5 is an edge generation circuit that generates edge data, 6 is a display output circuit that outputs to a display, and 10 is a display. Figure 2 shows the selection circuit 3 in Figure 1.
This is a circuit diagram showing the configuration of the circuit. In the figure, 7 is a first inverter circuit, 8 is a second inverter circuit, and 9 is a select circuit.

Next, the operation will be explained. The stored data stored in the display storage circuit 2 is sequentially outputted to the tC character storage circuit 1. At this time, the stored data specifies pattern data stored in the character storage circuit 1.

The specified parallel pattern data is output to the shift register 4.

Shift register 4 frames serial data and generates circuit 5
The border generation circuit generates border data, and outputs the pattern data to the selection circuit 3 and the border data to the display output circuit 6 through serial pattern data.

The selection circuit 3 that has received the pattern data inverts or non-inverts the data separately output from the display storage circuit 2 and outputs it to the display output circuit 6. The operation at this time will be explained with reference to FIG. The pattern data output from the border generation circuit 5 is selected by the select circuit 9 as to whether the input pattern data is output through the first inverter circuit 7 or not through the first inverter circuit 7 using the remaining data in the display storage circuit 2. do. The display output circuit 6 synthesizes inverted or non-inverted border data and pattern data and outputs the result to the display 10. The edge generating circuit 5 is the same as that of the conventional circuit.

Therefore, since border data is generated before the selection circuit 3,
The edges of the inverted pattern data and the edges of the non-inverted pattern data can be made the same.

Therefore, whereas conventionally N select circuits 9a to 9f were required to invert or non-invert parallel pattern data, in this embodiment, N select circuits 9a to 9f are required to invert or non-invert serial pattern data. In addition, the select circuit 9 can be configured with one piece.

In the above embodiment, the border generation circuit is constructed as shown in FIG. 5, but any circuit may be used as long as it can generate a border. Further, any type of device may be used as long as a plurality of shift registers 4 are used for edging, or the output of the shift register 4 can be outputted by an edging generation circuit as edging data and pattern data.

〔Effect of the invention〕

As described above, according to the present invention, since the selection circuit that was between the character storage circuit and the shift register is provided after the border generation circuit, the border in the basic data and the border in the inverted data can be made the same. At the same time, the number of selection circuits can be reduced, and when integrated into an IC, the chip area can be reduced.

[Brief explanation of drawings]

1 is a block diagram of a screen display device according to an embodiment of the present invention, FIG. 2 is a circuit diagram of the selection circuit shown in FIG. 1, FIG. 3 is a block diagram showing a conventional screen display device, and FIG. FIG. 3 is a circuit diagram of the selection circuit, FIG. 5 is a block diagram showing an embodiment of the edge generation circuit in FIGS. 1 and 3, and FIG.
a) - (dl is an explanatory diagram showing the display of a character whose basic data is bordered using the border generation circuit shown in FIG. 5;
FIG. 7 is a diagram in which data obtained by inverting the basic data shown in FIG. 6 is bordered using the border generation circuit shown in FIG. In the figure, 1 is a character storage circuit, 2 is a display storage circuit, 3 is a selection circuit, 4 is a shift register, 5 is an edge generation circuit, 6 is a display output circuit, 7 is a second inverter circuit, and 8 is a second inverter circuit. The inverter circuit and 9 indicate a select circuit. In the drawings, the same reference numerals E indicate the same or equivalent parts.

Claims (1)

[Claims] A character storage circuit that stores pattern data of a plurality of characters in a screen display device that displays one or more characters by using a plurality of pixels as one dot and composing one character with the plurality of dots. ,
a display storage circuit for specifying arbitrary pattern data of the character storage circuit; a shift register for converting the parallel output of the pattern data, which is the output of the character storage circuit, into a serial output; A border generation circuit which has the output of the register as an input, pattern data as one output, and border data forming a border around a dot indicated by the pattern data as the other output; and a border generation circuit using information from the display storage circuit. A selection circuit that selects inverted or non-inverted pattern data as an output; border data that is the other output of the border generation circuit; and a display that outputs the output data of the selection circuit to a display. A screen display device characterized by comprising an output circuit.