KR920002108Y1 - Coordinate latching device on display of writepen for crt - Google Patents

Abstract

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Description

On-screen coordinate latch device for light pen for cathode ray tube terminal

1 is a block diagram of the present invention.

2 is a detailed circuit diagram of the waveform shaping circuit and the latch pulse generator of the present invention.

3a-g is a signal waveform diagram of each circuit part of the present invention.

* Explanation of symbols for main parts of the drawings

1: waveform shaping circuit 2: latch pulse generator

4: X axis counter 5: Y axis counter

6: latch circuit

The present invention receives a pulse generated by a switch that is activated when a light pen for a cathode ray tube terminal is pressed against a screen, and outputs it by latching an XY coordinate that determines which line the vertical pen and the horizontal axis of the light pen are located on. An on-screen coordinate latch device configuration of a light pen for a cathode ray tube terminal.

Conventional light pens used to draw pictures on the cathode ray tube terminal screen have to find the coordinates where the light pen is located when the light pen is placed anywhere on the screen. There was a problem of requiring a device for supplying.

Accordingly, the present invention has been made in view of the above-described object of the present invention to provide an on-screen coordinate latching device for a light pen capable of latching and supplying on-screen coordinates of a light pen for a cathode ray tube terminal. The device will be described in detail as follows.

First, the configuration of the present invention is as shown in Figures 1 and 2 of the waveform circuit 1 composed of a resistor 101, a capacitor 102 and an inverter 103, 104 to which a pulse signal is input from a light pen. Output (A) is connected to a latch pulse generator (2) consisting of an OR gate (203) and an inverter (204) and an AND gate (205), and the output (B) of the latch pulse generator (2) is a dot clock generator (3). ) Is shared with the counter stop control terminals Co and C _{1 of} the X-axis counter 4 to which the dot clock DCLK is input and the Y-side counter 5 to which the horizontal synchronization signal H-syn is input as a clock. And the outputs of the X-axis counter 4 and Y-axis counter 5 are connected to the latch circuit 6 having the enable output terminal OE connected to the output C of the latch pulse generator 2. will be.

Effects of the present invention configured as described above are as follows.

First, as shown in FIG. 1, the waveform shaping circuit 1 receives an output pulse of a light pen on a cathode ray tube screen, removes noise, and waveforms a digital signal to apply to the latch pulse generator 2.

Accordingly, the latch pulse generator 2 receives the digital signal to output the stop signal of the X-axis counter 4 and the Y-axis counter 5 and outputs the enable signal output of the latch circuit 6. Output (C).

That is, data corresponding to the X and Y coordinates retrieved by the X-axis counter 4 and Y-axis counter 5 is latched to the latch circuit 6 and outputted.

In more detail with reference to FIG. 2, the inverters 103 and 104 are removed after noise is removed from the resistor 101 and the capacitor 102 by a predetermined pulse generated by a switch operated when the light pen is pressed on the screen. Through this, a digital signal (Fig. 3A) is generated and applied to the clock terminal CK of the D flip-flop constituting the latch pulse generator 2.

On the other hand, since the horizontal synchronizing signal H-syn is supplied to the input terminal D of the D flip-flop 201 through the OR gate 203 as a high signal (Fig. 3B), the output of the D flip-flop 201 is Goes high. In addition, the dock is applied to the output of the lock generator 3 (second 3c or one side of the AND gate 205), and the other input of the AND gate 205 (higher 3f) is a high state. At the output of the gate 205, this dot clock is output (Fig. 3e) and applied to the clock terminal CK of the flip-flop 202.

As a result, when the output Q of the D flip-flop 202 is inverted from high to low, the AND gate 205 is disabled so that the output of the dot clock generator 3 is no longer the clock terminal of the D flip-flop 202. CK), so that the output (Q: 3f) of this D flip-flop 202 is the count stop control terminals (Co, C) of the X-axis counter 4 and Y-axis counter 5 of FIG. ₁ ), the X and Y coordinates of the light pen are adjusted by ending the coefficients.

In addition, the output of the D flip-flop 202 (Q: FIG. 3g) goes high from low, and this signal is applied to the enable output terminal OE of the latch circuit 6 in FIG. The X-axis data and Y-axis data stored in (6) are outputted.

In the present invention, the flip flip flops 201 and 202 are inverted by the inverter 204 and applied to the clear CLR through the OR gate 203. ) Will be cleared.

According to the present invention as described above is a practical design that can obtain the coordinates of the light pen for the cathode ray tube terminal by a simple circuit configuration and supply to the computer circuit.

Claims (1)

The output A of the waveform shaping circuit 1, which is composed of the resistor 101, the capacitor 102, and the inverters 103, 104, to which the pulse signal is input from the light pen, is connected to the D flip-flops 201 and 202 and the OR gate ( 203 and a latch pulse generator 2 having an invertor 204 and an AND gate 205, and the output B of the latch pulse generator 2 is connected to the dot clock DCLK from the dot clock generator 3 by the dot clock generator. The X-axis counter 4 and the horizontal synchronization signal H-syn inputted together are connected to the count stop control terminals Co and C1 of the Y-axis counter 5, which are inputted as a clock, and the X-axis counter 4 And Y-axis counter 5 output the on-screen coordinate latch of the light pen for a cathode ray tube terminal with the enable output terminal OE connected to the latch circuit 6 connected to the output C of the latch pulse generator 2. Device.