JPS58205182A - Crt 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 The present invention relates to a Rusk scan type shade & line 1 display device, and particularly to a display device capable of displaying two or more pieces of screen information on the same display surface.

For example, when displaying figures and characters on the same display screen, the character codes are sequentially output from the first memory that stores the character codes, converted into character patterns corresponding to each character code, and each character is Dots are sequentially displayed on the horizontal scanning line with the horizontal synchronization signal as the starting point. The horizontal synchronizing signal is generally created as a basic counter that successively reads character codes from the first memory, and an integer number of characters are arranged and displayed on one horizontal scanning line.

On the other hand, if the character display is 1f, for example, graphical information, or if the number of dots in the upper d-pi character is different from the number of dots in the horizontal direction of the character, it is stored in the second memory.
The number of graphic units placed on one horizontal scanning line, fL, is not necessarily an integer. Therefore, even if graphic information is output from the second memory at an appropriate count period, it cannot be made to match the period of the horizontal synchronizing signal and the image flows, so it may not be possible to superimpose the image. If the storage units of the second memory are configured to be exactly an integer number during the horizontal synchronization signal period, it is possible to synchronize up to 5 (this is a major constraint on the memory configuration for graphic information. In addition, when Ii several pieces of 1-shape information are arranged within the horizontal synchronization signal period, the horizontal surface period is not necessarily an integral multiple of the graphic information, so there is a drawback that some of the displayed graphics may be deleted. Therefore, the conventional device described above has the disadvantage that it is extremely difficult to superimpose a character display in units of an arbitrary number of dots and a graphic display in units of an arbitrary number of dots.

It is an object of the present invention to solve the above-mentioned conventional drawbacks, and to perform continuous counting of character information, graphic information, etc. stored in a first memory and a second memory, each of which is configured in units of a desired number of dots. It is an object of the present invention to provide a cathode ray tube display device capable of displaying graphic information stored in another memory in synchronization within one period of a horizontal synchronization signal based on a number.

The display device of the present invention has a character display system that sequentially displays character information, etc., stored in a first memory at a constant cycle and displays it on the display device, and graphic information, etc., stored in a second memory, which are different from those described above. The above-mentioned Ail graphic display system that reads out information at intervals is characterized in that it includes means for reducing the readout cycle to 61 after a certain number of information readings.

Next, the present invention will be explained in detail with reference to the drawings.

The figure is a block diagram showing one embodiment of the present invention. This embodiment includes a character display system A that displays one character in units of dots for 9 pixels in the horizontal direction, and a graphic display system B that displays graphics in units of dots for 16 pixels. Display system A.

An example will be described in which a character display and a graphic display are superimposed and displayed on the same cathode ray tube display section 7 using the output of B1. Oscillator 1 that outputs a pulse signal for each ip
and frequency division ``#2'' which divides the output pulse of the oscillation vS1 by 9.
Then, count the output pulses of frequency divider 2 and count 11.
1 as an address signal to the memory 4 and outputs a horizontal synchronizing signal when the number of input pulses is an integer multiple of 9 after a full count, and a first memory that stores the character code of the character to be displayed. 4, a character pattern conversion circuit 5 that converts the character code output from the first memory 4 into a dot pattern, and a video circuit 6 that converts the dot pattern output from the character pattern conversion circuit 5 into a video signal and outputs it.
The count value of the counter 3 is updated every nine output pulses of the oscillator 1, character codes are sequentially read out from the first memory 4, converted into a dot pattern Kf by the character pattern conversion circuit 5, and then converted into a dot pattern Kf by the character pattern conversion circuit 5. 6, the signal is converted into a video signal and characters are displayed on the display section 7. The horizontal scanning of the display 1157 is performed in synchronization with the horizontal synchronization signal output from the counter 3. The above is the same as the conventional display device.

On the other hand, the graphic display system B stores graphic information in units of 16 dots in a second memory, io, and the graphic information stored in the address position specified by the output of the counter 9 is output from the counter 9. The signals are sequentially read out, converted into video signals by the video circuit 11, and folded into the output of the video circuit 6.

The counter 9 counts the output pulses of the divided period 8 and outputs the count value as an address signal for the second memory IO. On the other hand, the counter 12 operates in synchronization with the output of the counter 9, and outputs an output signal when it counts 54, for example, to change the division ratio of the divider 8 to, for example, 1/18.

The frequency divider 8 is a circuit that normally divides the output pulse of the oscillator 1 by 1716, or it is a divider that changes the frequency to 1/18 M1 by the output signal of the L counter 12. In this embodiment, the frequency divider 8 and the counter 12 constitute ``means for varying the readout period for outputting a constant amount of information [7 numbers σ]''.

Now, counter 3σJ force count period Nt of character display thread A
is 9t, and 19 within 1 horizontal opening period signal TH
For example, when the number of P counts N and l is 106, and when the i-dot display time t is 33 nanoseconds, one horizontal period signal period TH is 31.482 microseconds. Of course, this also includes the horizontal blanking time, so the number of displayed characters is less than 106. Then, from the second meshichi IJ 10, one pheasant figure is read out every 16 degrees, so the 54 degree figure is 28.512.
It is displayed in microseconds, and then the readout period is changed so that five units of figures are read out every 18 pulses, ie, every 2.970 microseconds. By making this period shorter than the horizontal blanking time unrelated to display, the total time can be reduced to 31.482 microseconds without displaying this portion on the display screen.

That is, 31. which is output by the counter 3 of the character display system A.
It is possible to synchronize to a horizontal synchronization signal every 482 microseconds.

Generally speaking, the display time t12 of one dot on the display unit
When the character count cycle Nlt, , character count number in one horizontal opening signal cycle is &MHI, the count cycle of graphic information is N, t, and the number of graphic information read is NH□. , horizontal synchronization signal TH is TH=N1t, XNH1=N, tpXNH,...
....If (1) is not achieved, synchronization will not be achieved, but in the present invention, the above equation (1) is changed, and TH= N1 t,
'p XNMH!・・・・・・・・・・・・(2) Synchronization is achieved by doing the following. However, Nto 2
Of the counts in the horizontal synchronization signal, the readout cycle of the unit N11 report is different from the normal N2t (X)! ”
iaz'p is the count number, and NMH2 and 8M2 are appropriately selected so as to satisfy equation (2).

However, NM2×NMH2×tp is selected to be smaller than the horizontal blanking time. In the above embodiment, NM
Since we selected □=l 8, NM, 2=5, NM
2×NMH2X tp=2.970 microseconds. In other words, the bladder ejection cycle from the second memory is read out at a cycle of N2t up to a certain number (NM2'MH2), and then NM2t within the horizontal blanking time.
The cycle was changed to 2tll, and by adding five cycles of this cycle to the previous graphic display time, it became possible to match the horizontal synchronizing signal cycle TH. In general, even if the reading cycles of unit information of the first memory and the second memory are arbitrarily independent, the NMH2 that satisfies equation (2)
and NM□, and the only σj constraint is that NMH2×NM2×tp is less than the horizontal blanking time. Traditional.

Due to the constraint of Equation (1), it is not possible to perform synchronized display for any arbitrary readout cycle of the two systems. The effect is that the output signals of the two systems to be displayed can be easily folded and displayed on the same display section, matching the horizontal synchronization signal determined by one system, and the output signal of the other system. have

[Brief explanation of the drawing]

The figure is a block diagram showing one embodiment of the present invention. In the figure, l... oscillator, 2, 8... divided period, 3
゜9...Counter, 4...First memory, 5...
Character] turn conversion circuit, 6.11... video circuit,
7.--Display section, 12..Counter, lO.--Second
memory, A...Character display system, B...Graphic display system. Agent Patent Attorney Sumi 1) Sou Toshi [−□−−1−□伜□−Shizuku−]

Claims (1)

[Claims] a character display system that reads out character information, etc. stored in a first memory at a constant cycle and displays it on a display device; and a character display system that reads out graphic information, etc. stored in a second memory at a different cycle from the above-mentioned display device. A rusk scan type cathode 7μ display device comprising a graphic display system for displaying information in a superimposed manner, characterized in that the graphic display system is provided with means for varying a readout period after the number of information readouts of −5Z. Extremely durable display device.