KR900010343Y1 - Double hight cursor - Google Patents

Abstract

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Description

DOUBLE-HEIGHT CURSOR CIRCUIT

1 is a detailed circuit diagram of a double height cursor circuit of the present invention.

2 is a double height cursor circuit operation state of the present invention.

3 is an exemplary view showing a state displayed by the present invention double height cursor circuit.

* Explanation of symbols for main parts of the drawings

CPU: Central Processing Unit D ₀ -D ₇ : Line Data

line counter: Line counter O ₀ -O ₇ : Output data

Comp ₁ : Comparator EXoR ₁ -EXoR ₈ : Exclusive Oagate

AND ₉ -AND ₁₆ : AND gate D / H: Double height

/ B: series signal

The present invention relates to a cursor circuit applied to a CRT terminal of a personal computer, and more particularly, to a cursor circuit in which the double height function (double space function) of the cursor circuit is solved by hardware.

The cursor circuit is a circuit having a function of editing a document such as a life writer or a printer. Up to now, it has been known that the operation is performed by the cursor control of the complete software according to the system programming of the central processing unit. In other words, the cursor circuit performs a write function on the screen under the control of the central processing unit. The cursor circuit is a system using a RAM memory, direct memory access, and a write function during a vertical period, which is called a programmable peripheral interface. As this peripheral has a service routine associated with it, it is programmed by the I / O service routine and has an extension of the system operating software. Therefore, the control words of these interfaces must be newly developed to operate the programmable peripheral interface for application to the application.

Accordingly, the technical disadvantages of the conventional conventional apparatus, that is, the data value of the line designating the position of the cursor from the central processing unit are directly input to the comparator, for example, of the interface circuit, and the input value is inputted to the line counter. The vertical cursor enable signal is output for the same period compared to the current output value of.

Therefore, because the vertical cursor enable signal outputs only one line signal, the interface outputs only one line when the line property signal is a double-high signal. The state of the attribute signal of the cursor line is displayed on the display device. It was necessary to check the display status as the key was operated again while checking.

Accordingly, an object of the present invention is to provide a cursor circuit with a new double-height function that allows character line determination of a cursor by hardware to enable character graphics at the convenience of the operator regardless of the software of the interface. In order to realize the present invention, the present invention provides the A port of the comparator driven according to the control programming through the AND gate and the exclusive OA gate for the line data value that designates the cursor position from the central processing unit, the attribute signal and the serial output data of the double height. The cursor position specifying line data is the most significant line when the double height attribute signal and the serial output data are set by inputting the output data of the line counter indicating the current line position to the B port of the equivalent comparator. If is the value of the specified line and the line car In the case of the lowest line that outputs the vertical cursor enable signal and specifies the cursor position compared to the output data of the data, increase the value 1 to the value input to the A port of the equivalent comparator to the line designated by the CPU and the next line. The vertical cursor enable signal is output so that the double height cursor is configured to be displayed.

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

Line data (D _0- D ₇ ) designating the cursor position from the CPU, and output data (O _0- O ₇ ) indicating the current line position from the line counter (A ₀ -O ₇ ). _0- A ₇ ) and a cursor circuit having a comparator Comp ₁ for outputting a vertical cursor enable signal by comparing them through the B port (B _0- B ₇ ), the CPU unit from the CPU. The line data ((D _0- D ₇ ) that specifies the cursor position is the one-side input terminal of the exclusive oragate (EXoR ₁ -EXoR ₈ ) whose output is connected to the A port (A ₀ -A ₇ ) of the comparator (Comp). in addition to the connection box and an output terminal connected to one of input terminals of the aND gate (aND ₁₀ -AND _16), and the other input terminal of the aND gate (aND ₁₀ -AND ₁₆₎ of the XOR gate Iowa (EXoR ₁ -EXoR ₈₎ The output terminal of the (AND ₉ -AND ₁₆ ) connected to the other input terminal of the AND gate (AND ₁₀ -AND ₁₆ ); Both input terminals of the AND gate (AND ₉ ) have a double height terminal (D / H) and a series signal terminal ( / B) to connect.

Referring to the effect of the present invention configured as described above are as follows.

First, power is supplied to the personal computer, and various character data is input using the cursor circuit, and then the double height (D / H) and the serial output ( / B) are all "0" input when the AND gate (AND ₉₎ of the output is "0", so the central processing unit (port (A ₀ -A of the comparator (Comp) without data changes representing the designated line from the CPU) ₇ ) and an output indicating the current line position from the line counter is applied to the ports B ₀ -B _{7 of the} comparator Comp and the comparator Comp shown in FIG. As described above, the data of the ports A ₀ -A ₇ and the ports B ₀ -B ₇ are compared to output a vertical cursor enable signal when the data are the same.

In addition, double height (D / H) and serial output ( / B), as shown in (b) and (c) of FIG. 2, when "0" is input, the output of the AND gate AND ₉ becomes "0", and thus, as shown in (a) of FIG. You get the same result. However, in the cursor circuit, as shown in FIG. 2 (d), the line double height (D / H) and the series forming output ( / B) If all data of "1" is inputted, the output of AND gate (AND ₉ ) becomes "1" and it adds "1" to the data (D ₀ -D ₇ ) of the cursor line designated by the CPU. Is applied to the ports (A _0- A ₇ ) of the comparator (Comp), and the current line position data, which is the output of the line counter, is applied to the ports (B ₀ -B ₇ ), so that the comparator (Port) When the data of (A ₀ -A ₇ ) and the ports (B ₀ -B ₇ ) are the same, the vertical cursor enable signal is generated.

An example of this is as follows.

FIG. 3a shows the case where the attribute data is shown in FIG. 2a, FIG. 3b shows the case shown in FIG. 2c, and FIG. 3c shows the case shown in FIG. 2d that the cursor is in a normal state when the ninth line is designated from the CPU. If the 10th line is specified, the cursor is displayed on line 2, which is the double height (D / H) state. In line 10, as shown in FIG. If only the line is displayed and the line counter is increased to the 11th line, the line attribute data becomes the second d, and 1 is added to the line 10 designated by the CPU to become 11 lines. Compared to the output of line counter (O ₀ -O ₇ ), the cursor is displayed on the 11th line. Therefore, the cursor secures a line value from the line designated by the CPU to the line designated by the vertical cursor enable signal, and displays predetermined characters during the vertical period.

As described above, the present invention determines the line determination of the cursor by hardware, thereby providing an advantage of enabling character graphics for convenience of operation regardless of software.

Claims (1)

Line data (D _0- D ₇ ) designating the cursor position from the CPU, and output data (O _0- O ₇ ) indicating the current line position from the line counter (A ₀ -O ₇ ). _0- A ₇ ) and a cursor circuit having a comparator Comp ₁ for outputting a vertical cursor enable signal by comparing them through the B port (B _0- B ₇ ), the CPU unit from the CPU. The line data ((D _0- D ₇ ) that specifies the cursor position is the one-side input terminal of the exclusive oragate (EXoR ₁ -EXoR ₈ ) whose output is connected to the A port (A ₀ -A ₇ ) of the comparator (Comp). And an output terminal of the AND gate (AND ₉ -AND ₁₅ ) connected to an input terminal of one end of the AND gate (AND ₁₀ -AND ₁₆ ), and to an input terminal of the other side of the exclusive OGATE (EXoR ₁ -EXoR ₈ ). connecting the output of said AND gate (AND ₁₀ -AND ₁₆₎ the AND gate (AND ₉ -AND ₁₆₎ connected to the other input terminal of the The said AND gate (AND ₉₎ The positive input terminal of the double-height attribute of the terminal signal (D / H) and the serial signal terminal of the shape ( / B) is a double height cursor circuit characterized in that the connection.