JPS6150188A - Screen display unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a screen display device that prevents errors in display positions of characters and figures displayed on a screen.

2. Description of the Related Art Conventional Structures and Problems Many screen display devices have been used that display characters and figures on a screen to display various information in an easy-to-understand manner.

A conventional screen display device will be explained below.

FIG. 1 is a block diagram of a conventional screen display device. 1 is an oscillator, which is connected to the clock input of presettable counter (hereinafter referred to as P counter) 2 and the input of gate 4, and the output of P counter 2 is connected to the input of RS flip-flop (hereinafter referred to as R8FF) 3. The horizontal synchronization pulse is connected to the reset input of P counter 2, the reset input of R8FF3, the clock input of P counter 6, and the input of gate 8. Further, the output of R3FF3 is connected to the input of gate 4, the output of gate 4 is connected to the input of counter 5, and the output of counter 5 is connected to the input of data memory 12. Also, the vertical synchronization pulse is connected to the reset input of P counter 6 and the reset input of R5FF7.
The output of counter 6 is connected to the input of R3FF7, and R5
The output of FF7 is connected to the input of gate 8, the output of gate 8 is connected to the clock input of counter 9, and the output of counter 9 is connected to data memory 12.
The output of 2 becomes the screen display output. The output of the circuit A1o is connected to the P counter 2, the output of the circuit B11 is connected to the P counter 6, and the data memory 12, latch A10 and latch B11 are connected to the data line.

The operation of the screen display device configured as described above will be described below.

First, horizontal position data is set in latch A10.

This set value is set in the P counter 2 at the timing of the horizontal synchronizing pulse, and the gate 4 is closed while the output of the oscillator 1 is counted up to this set value. Thereafter, the gate 4 is opened and the output of the oscillator 1 is input to the counter 6. That is,
Since the output of the oscillator 1 is not added to the counter 5 up to the value set by the latch A10, the horizontal position can be set. Similarly, in the vertical direction, vertical position data is set in latch B11. This set value is set in the P counter 6 at the timing of the vertical synchronizing pulse, and the gate 8 is closed while counting the horizontal synchronizing pulses up to this setting. After that, gate 8 opens and horizontal synchronization pulse is sent to counter 9.
is input.

That is, the horizontal synchronizing pulse is not applied to the counter 9 up to the value set in the latch B11, and the vertical position can be set.

However, in the above configuration, the horizontal position setting and vertical position setting are independent, so the horizontal position setting is performed for each horizontal sync pulse, the vertical position setting is performed for each vertical sync pulse, and the horizontal position setting is performed for each vertical sync pulse. Since the settings are made more quickly, there is a problem in that the display appears at a different position on the screen.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned conventional problems, and provides a screen display device that prevents displaying information in the wrong position on the screen.

Structure of the Invention The present invention is a screen display device that determines a display position on a screen based on a horizontal synchronization pulse and a vertical synchronization pulse,
By providing a means for simultaneously setting the horizontal and vertical positions, it is possible to prevent displaying in the wrong position.

DESCRIPTION OF THE EMBODIMENTS FIG. 2 shows a block diagram of a screen display device according to an embodiment of the present invention. Reference numeral 22 denotes a latch A1, the output of which is connected to the P counter 14, and the latch pulse is a vertical synchronization pulse. It is connected to the. Also, 23 crawl/notch A2 and its output is 22 latch A1
and the input is connected to the data line. In addition, 13 is an oscillator, 14 is a presettable counter, and 16
is an RS flip-flop, 16 is a gate, 17 is a counter, 18 is a presettable counter, 1 RS flip-flop, 20 is a gate, 21 is a counter, 24 is a latch, and 25 is a data memory. It is the same as the configuration.

The operation of the screen display device of this embodiment configured as described above will be described below. First, the horizontal position data is 23
Nou 1. This held data is connected to the presettable counter 14 through the latch A1 of 22, and the latch input of the latch A1 of 22 is a vertical synchronization pulse. No matter what timing the horizontal position data is set in latch A2, new data will be set in the P counter 14 after the vertical synchronization pulse.Other operations are the same as the conventional example. According to the configuration of the embodiment, it is possible to set the horizontal position and vertical position at the same time, preventing display from being displayed in the wrong position, and it is easy to change from the conventional example, improving performance at low cost. I can do that.

In this embodiment, a latch is added to synchronize with the vertical synchronization pulse, but the same effect can be obtained even if the horizontal position is set during the vertical synchronization period without adding a launch. In this case, an additional circuit called a latch is not required, but there is a time constraint in that the vertical synchronization period must be detected and data must be set during that period. Since it is equipped with a means for setting the vertical position at the same time, the horizontal position and vertical position will be at the set position at the same time.
This allows the display position on the screen to be displayed without shifting from the set position.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional screen display device, and FIG. 2 is a block diagram of a screen display device according to an embodiment of the present invention. 1.13...Oscillator, 2,6,14.18...
...Presettable counter, 3, 7, 15.19
...RS flip-flop, 4, 8, 16.2
0...Gate, 5, 9, 17.21...
・Counter, 10°11.22, 23.24...
・Latch, 12, 25...Data memory.

Claims (1)

[Claims] A screen display device that determines the horizontal and vertical positions on the screen based on horizontal synchronization pulses and vertical synchronization pulses in order to display characters and figures on the screen, and includes means for simultaneously setting the horizontal and vertical positions. A screen display device characterized by: