DE3206565A1 - CONTROL ARRANGEMENT FOR A VIEWING DEVICE - Google Patents

Description

A.P. Ross - 1

Control arrangement for a data display device

The invention relates to a control arrangement for a data display device with a cathode ray tube on its screen row-wise oriented data in a sequential way repeated raster display.

Control arrangements of the aforementioned type are known, one of which is shown in FIG. 1 in the form of a block diagram is.

The control circuit of Figure 1 has a main processor (MPU) 1 which receives data from a data source such as an input keyboard (not shown), incoming data is processed. The processed data is processed by the processor 1 to a screen control (CRT) 2, the output signals of which are fed to a monitor 3 for displaying the Initiate data.

The CRT controller 2 comprises four logical circuit areas:

a) A random access memory (RAM) 4 in which all characters to be displayed and associated at-

ZT / P1-vHy / fö - 4 _

16.o2.1982

A.P. Ross - 1

tribute (identifiers) can be stored in a simple binary-coded form. They are in general stored in the order in which they are displayed on the screen (not shown) will.

b) A clock 5, which contains a high-frequency oscillator. Its output is with a frequency divider connected, which derives different clock frequencies from the oscillator frequency. These are used for general Coordination of the control logic, for positioning the characters on the screen and for generating the necessary synchronization pulse sequences for the monitor 3.

c) A character generator 6 in the form of a ROM and a

Parallel / serial converter 7, which are used to convert the characters contained in the memory 4 in coded form into a to convert complex serial data form corresponding to the screen display.

d) An identifier generator 8, the certain Kerin drawings generated, such as increasing the brightness, reverse video (black characters on a light background) and blinking. The individual identifications can optionally be assigned to the character fields on the screen.

The raster image monitor 3 is on the clock 5 with horizontal and vertical synchronization signals.

The signaling signals from the converter 7 and from the generator are fed to the monitor 3 via a mixer 9. This has, in a known manner, a cathode ray tube with deflection coils and contains the necessary for the operation of the tube Switching means.

APRoss - 1
This control circuit consists of:

a) A video amplifier that absorbs the relatively weak signals which are output from the screen control 2, amplified so far that a sufficient modulation of the electron beam of the picture tube is guaranteed.

b) A syndaronization and deflection circuit which is carried out by the vertical and horizontal syndronization signals of the screen control 2 is activated and by the the grid line field is formed, which is modulated according to the characters to be displayed.

One of the most advantageous possibilities offered by the control according to the invention is a jump-free movement the screen content (soft scrolling). Here leaves the screen content of a digitally generated raster image at different speeds and move in opposite directions without the viewer feeling a step-by-step movement. This is achieved by changing the position of the data field at a speed that is faster than that Sluggishness of the eye and the luminous layer of the screen. In order to obtain a flicker-free image, this speed must be equal to or greater than the frame rate.

Using an exemplary embodiment, the invention is described in more detail in conjunction with the drawing FIG. 2, which shows in a block diagram the address and data flow of a control circuit which replaces that of FIG. the end For the sake of clarity, only the control lines required to understand the invention are shown. For

A.P. Ross - 1

The reference numerals from FIG. 1 have been adopted for blocks with the same function.

In the following text, “line” is to be understood as a single grid field line, while a group of grid field lines form a “line” within which the individual characters are formed. Each line is divided into a grid-like manner, parts of a character to be displayed being formed by the individual grid points.

A two-way buffer memory 1o serves the main processor 1 To input or read out data in a random access memory (RAM) 4a. The latter can be the same or similar to the RAM 4 of FIG. Its function is, however, expanded compared to the RAM 4, since it is in addition to the coded Characters and identifications Control commands are entered in digital form, indicating the type of representation of the characters determine.

Furthermore, a 3-on-1 multiplexer 11 is provided over For each read / write operation, the corresponding MPU address is entered into the memory 4a. Farther every time the screen grid is to be modulated to display a character, the memory 4a a row address is supplied which includes row, frame and control logic editing information. Entering the Row addressing takes place during the horizontal and vertical beam return, since no video data are given to the monitor 3 during this time.

A block 12 comprises a series of buffer memories which are clocked differently. The clock marks are either based on a character period, a line period or a frame or sub-frame period. A subframe period

• ♦ ··· «ii *

A.P. Ross - 1

ode encompasses several line periods, e.g. an attribute can be set in the second display line which is contained in the eighth display line is deleted again. Of the The letter "C" means line information, "R" means line information and "F" means frame or subframe information.

Processing information for the controller, such as the number of characters per line, the number of grid lines per line, the number of rows per frame, as well as the Setting and the length of the horizontal and vertical synchronization signals are all made by the program of the Main processor 1 specified as part of the system preparation. The control part can therefore be programmed entirely to the needs of the user and to various requirements of the monitor.

The character generator 6 is a pest value memory (ROM), in which the character set is stored in matrix form, whereby they are available in a decoded form, the is determined by the subdivision of a screen line in a line grid. The doing of each individual grid line assigned character parts can be read out via the address assigned to each line. Through a If the line addresses of a line are called up one after the other, those to be displayed in the respective row are displayed Characters constructed in the form of a dot matrix.

Through the parallel / series converter 7, the parallel offered Output data of the character generator 6 transferred in serial form. This provides the video output of the screen control 2 to monitor 3, if not in mixer 9 a mixture with one of the available attri

• · ♦

A.P. Ross - 1

bute takes place, optionally from a license plate generator 2o can be selected.

A programmable counter 13 is powered by a crystal oscillator 21 clocked. This counter 13 counts the number of matrix points over the width of each character field. With a constant division from character to character, the counter 13 is set to a predetermined count. With proportional step control, the counter can be set character by character. This is done either by in the random access memory (RAM) 4a with stored character width information or by a separate read-only memory (ROM), not shown, in which the character widths are assigned to the individual characters and which can be individually selected via the character code.

The crystal oscillator 21 also clocks one of several programmable ones Counter with associated decoding logic comprehensive control stage 14, which is necessary for the operation of the monitor 3 provides horizontal synchronization pulses. The counters of this control stage also emit control signals, via the \ character, line and frame buffers and other parts of the screen control 2 are clocked.

A line / line counter 15 consists of two programmable counters, both of which are initialized via the CRT control will. The line counter starts counting and counts at the beginning of each horizontal dark control period each line from zero to the preprogrammed number of lines that make up the respective line. The line counter counts from zero to the number of preprogrammed lines per frame, plus one more counting process,

■ · · · · » te

A.P. Ross - 1

which is necessary to return the darkly scanned write beam to the starting position.

via a character counter 16 and its line attribute programming it is possible the entire field or certain areas of the screen in horizontal or vertical Move direction without jumps. The counter 16 can be programmed to each individual character address in the memory 4a and then incremented to a value corresponding to the number of characters per line before it is passed through the buffer memory 12 (the control stage 14) is reset - This process allows anyone to include a line of characters Section of the memory 4a in each line of the screen. During every horizontal dark phase a row address generated by the double memory 15 and belonging to a sequence is supplied to the memory 4a. During the process of shifting the image field content line by line (hard scroll), the current line addressing a constantly changing line addressing entered into the memory 4a.

An adder 17 is provided, via which a horizontal (lateral) jump-free shift is possible. A horizontal one Shifting can be done in both directions for each individual line as well as for a combination of lines can be achieved via the adder 17 is the matrix point count the line identifier is added by the counter 13. With the resulting signal, the character counter 16 advanced. In the case of a stationary screen content, the line identifier offered via the adder 17 is Zero. A jump-free shift on the screen to the left with a character field width of new matrix points happens in the following way:

- 1o -

- 1o -

A.P. Ross - 1

1. At the end of an image cycle (at the beginning of vertical synchronization) the line identifier receives the value 1. This causes the characters to appear on the next .Image cycle can be displayed offset by one matrix point to the left compared to the previous image field.

2. At the end of the following seven image cycles, the line identifier has reached the value eight. This takes place a shift of the line to the left until only the last matrix point of the first, nine grid points, is left wide character field is shown on the screen.

3. To complete the jump-free shift to the left by one character width, the line identifier (at the end of the next picture cycle)

Reset to zero. The line start addressing which is again supplied to the counter 16 is for this line then one again.

In the case of a jump-free shift to the right, the process described is exactly the opposite. The one to the adder Line start addressing supplied to 17 is reduced by one to the value eight at the moment of entry. This line identifier is reduced by one to zero at the end of each of the following eight image changes.

Two adders 18 and 19 are provided for vertically shifting the image field content in both directions. A frame or sub-frame identifier is entered in the adder 18 added to the line address. The signal resulting therefrom reaches the adder 19, which does the row addressing forms. In the following, the frame or sub-frame

- 11 -

- τι -

A.P. Ross - 1

designation referred to as additional grid number. The sequence A jump-free shift of preselected lines, each consisting of fourteen lines, takes place as follows:

1. At the end of each picture cycle, the additional grid number is added increased by one at a time until the value thirteen is reached.

2 »At the end of the next vertical synchronization the additional grid number is reset. At the same time, the image content is suddenly shifted upwards by changing the sequence of line start addresses supplied to the character counter 16.

The initiation of a non-jumping vertical shift of the image field content downwards first triggers an abrupt one Shift down from. At the same time, the additional grid number is set to thirteen. This will make the for the area provided for displacement is shifted down by one grid line. In the course of the following picture cycles the additional grid number is reset by one to zero.

A faster shift can be achieved by using the Additional grid number per cycle is increased or decreased by more than one.

The available license plates (attributes) are in the license plate generator 2o stored. The line markings can consist of a line flashing, an increased brightness of the respective cell etc. exist.

- 12 -

- 12 -

A.P. Ross - 1

An image field identification can be the brightness of the image. (It allows the operator to adjust the brightness of the monitor via the keyboard). Another identification can be image field formatting.

It should be noted that both the vertical and the horizontal shift can also be limited to selected image field areas so that parts of the of the reproduced text (e.g. a heading) remain while another part is shifted.

The term "characters" or "characters" used is not to be understood as a restriction to alphanumeric characters.

2 sheets of drawings

- 13 -

-43 -

Blank page

Claims (5)

INTERNATIONAL STANDARD ELECTRIC
CORPORATION, NEW YORK A.P. Ross - 1 Claims Control arrangement for a data display device with a cathode ray tube, on the screen of which data oriented in rows are reproduced in a sequentially repeating raster display, characterized by a memory for the characters and character identifiers (attributes) to be displayed, to which control information is also entered, which in digitized form the type and Determine the way in which the stored characters are displayed on the screen. 2. Control arrangement according to claim 1, characterized in that the control information causes some of the characters displayed to maintain their position on the screen and that the remaining part of the characters can be changed in their screen position. 3. Control arrangement according to claim 2, characterized in / that the changeable part comprises one or more lines of characters which are perpendicular to their longitudinal extent gradually displaceable at a distance of a raster line. ZT / P1 - vHy / fö - 2 - 16.o2.1982 mm * y - A.P. Ross - 1 4. Control arrangement according to the preceding claims, characterized in that the characters are stored in the form of point matrices and that the control information causes one or more lines of characters to be shifted parallel to the rasterization step by step by the distance between two adjacent matrix points. 5. Control arrangement according to the preceding claims, characterized in that it is arranged between a main processor connected to a data source (keyboard) and a monitor with raster picture tube and that the control arrangement has a random access memory (RAM) for storing the characters and control information supplied by the main processor that interacts with other logic circuits required to digitally control the monitor.