JPS61123925A - Picture display device - Google Patents

Abstract

PURPOSE:To write data on a picture pattern received based on the discrimination in a pattern RAM by discriminating a writable position in the pattern RAM by referring to a list RAM when stored contents in the pattern RAM are updated. CONSTITUTION:A test RAM 10, the list RAM 15 are equipped as well as the pattern RAM 12, and the address of a writable font section (one unit section = one font) in the RAM 12 is linked and stored in the RAM 15. Referring to the contents stored in the RAM 15, a receiving/writing control part 8 discriminates the writable font section in the RAM 12, and rewrites the RAM 12 based on the discrimination. Clearing in case of screen clearing and screen scrool display is not made in such a way that data on a blank pattern is written in each on font section of the RAM 12, but merely modification of the contents stored in the RAM 10 is sufficient accordingly. As a result, said actions can be done at an extremely high speed.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention receives transmitted image pattern data, etc., and updates the storage contents of a pattern RAM with the received image pattern data. [Technology] Conventionally, it has been proposed to display characters and figures using subcodes of CDs (compact discs).

By the way, when displaying characters and figures, for example,
As described in Japanese Patent No. 5-2548, a predefined type of image pattern (dot pattern) is
When displaying an image by storing it in a memory such as M or a character generator, each image pattern stored in the memory or character generator, etc. Selectively read data (
There is a method for displaying on a display means such as 4T, and instead of storing and storing predefined types of image pattern data, sequentially receiving image pattern data and display position data, and displaying the received image pattern. There is a method of displaying data on a display means.

In the former method, the image pattern to be displayed is determined by image pattern data stored in advance,
While it is impossible to display other image patterns, the latter method has the advantage of displaying any image pattern because it displays the received image pattern, and image display using CD+- It is being considered to use the latter method.

By the way, the data of one image pattern is the data of 1 turns of each 1 unit of image when the display screen of the display means is divided into unit sections of characters and figures in a multi-IJ lux shape. Hereafter, each l unit section is defined as 1 font, -,.

In the case of a display device that displays an image using the latter method, each one-font image pattern data corresponds to the display position data on the display screen, for example, the IO row and 28th column of the screen ( 10.28) is transmitted together with the display position data.

Note that data indicating a display method, such as scroll display, is also transmitted.

Further, the received image pattern data of each I font is normally stored in a pattern storage memory, that is, a pattern RAM, which has a storage capacity of image pattern data for one screen or more, and based on the storage, the pattern RAM is stored. The contents are updated and images are displayed based on the data of each image pattern read from the pattern RAM.

Methods for storing and displaying image pattern data in the pattern RAM include a bitmap (full graphic) method and a text (programmer character image display) method, which will be explained below. When using this, the display block of the display device is configured as shown in FIG. 8(a).

In FIG. 8(a), (1) is a display control section consisting of an integrated circuit for a CRT controller, which generates memory addresses. (2) is a pattern RAM that stores received data of each 1 font image pattern;
Reading is controlled based on the memory address of the control unit (1). (3) is a parallel-to-serial converter connected to RAM (21), which converts the parallel/<9-n data read from RAM (2) into serial and outputs the serial pattern data to a display means such as CfLT. do.

Note that writing to RAM +21 is performed by a write control section (not shown) or the like.

In the case of the bitmap method, when displaying a monochrome image, each 1 bit of RAM (21) corresponds to each 1 dot on the display screen, and each 1 bit of data for each image pattern corresponds to one memory address. RAM (21) is stored at the position of RAM (21), which is controlled by writing and reading and is determined based on the display position on the display screen.

That is, the RAM (21) always stores image pattern data for each font at a position corresponding to the position of each font on the display screen, and at this time, the control unit (1)
1 bits of image pattern data correspond to one memory address output from the .

Note that when displaying a color image, it goes without saying that a plurality of bits in the RAM (21) correspond to one bit on the display screen.

The advantage of the bitmap method is that, as is clear from FIG. 8(a), only the pattern RAM +21 needs to be provided, so the configuration is simple and the circuit scale is small.

On the other hand, when performing screen scrolling display using the bitmap method, that is, vertically or horizontally scrolling the entire screen, the controller (1) sends R
The memory address output to A M +27 can be moved down or up one row or one column at a time. It is necessary to clear the column portion or write data for a new image pattern.

Furthermore, when scrolling a specific row or column of the display screen using the bitmap method, each time one screen display ends, the scrolling of a specific row or column of RAM +2) is performed.
It is necessary to rewrite and transfer the image pattern data for the columns.

Furthermore, when clearing the display screen using the bitmap method, that is, clearing the screen, it is necessary to clear the data of all image patterns in ELAM (2).

The image pattern data for each 1 font is usually 7~
RAM consists of a large number of bytes and has a large number of bits.
(It takes time to write a blank pattern for clearing in each font of 21 and clear it, and screen scroll display using the bitmap method, scroll display of one specific row or column, and clearing one screen can only be done at low speed. do not have.

Next, when using the text method, the display block of the display device is configured as shown in FIG. 8(b).

In FIG. 8(b), (4) is a display control unit consisting of an integrated circuit for the CIILT controller, which generates text memory addresses and raster addresses, which will be described later.

(5) is a text RAM whose readout is controlled by the text memory address, and (6) is a pattern RAM similar to the LeAM+21, which stores the received image pattern data of each 1 font, and A.M.
(5) Writing and reading are controlled by the pattern memory address output from the control section (1) and the raster address output from the control section (1). (7) is RAM (6)
It is a parallel-to-serial converter connected to FL A
The parallel pattern data read from the M161 is converted into 7-real data and output to a display means such as a serial pattern booter cRT.

Note that writing to the RAMs (5) and [61 is performed by a write control unit (not shown) or the like.

By the way, in RAM +61, the position of one font unit is addressed by one pattern memory address, and the position of each display scanning line of 91 fonts is addressed by raster address, and the pattern memory address and In combination with raster address, RA
The location of each display scan line for each of M +61 fonts is addressed.

Then, one pattern memory address specifies the position of one font unit of RAM +61 as described above, and at this time, one text memory address! Since the locations of two pattern memory addresses are addressed, the pattern memory address is the memory address output from the control unit (1) to fLAM (2) in FIG. 8(a), that is, the memory address of RAM (2). A memory address for addressing the location of each bit is typically formed from one to two bytes.

Further, one pattern memory address is addressed by one text memory address.

In other words, one text memory address allows one of RAM+6) to be accessed via one pattern memory address.
The position of the font unit is addressed.

Then, each text memory address is stored in the FLAM (5) in order of the display position on the screen, and the control unit (4)
The readout of R and A M (5) is sequentially controlled by the RAM (5), and the readout of RAM +61 is controlled based on the pattern memory address read out from the RAM (5).

Therefore, even if RAM (61) stores the data of each image pattern at an address unrelated to the display position, when displaying, the data of each image pattern will be read from RAM +61 in the order of display and will be displayed properly. displayed at the display position.

In the following description, one pattern memory address, ie, the address for reading data of the image pattern of l font, will be referred to as l vector.

Although the configuration is more complicated and the circuit scale is larger than that of the bitmap method, it has the following advantages.

That is, when the image data pattern of the displayed l font is moved to another location on the display screen for scroll display, etc., the bitmap method shown in FIG. 1(a) requires only RAM (2) It is necessary to rewrite and transfer the image pattern data of the l font, but in the text method shown in FIG.
), and in this case, rewriting the l vector in RAM (5) requires fewer bits than transferring 1 font of data in RAM (2). It can be done in a short time.

Therefore, when performing a flow display of one row or one column, it is only necessary to rewrite the vector in the RAM (5) corresponding to one row or one column, which has the advantage of being faster than the bitmap method.

[Problem that the invention seeks to solve]

By the way, when data of a one-font image pattern received using the bitmap method and the text method is stored in the pattern RAM, the received data is stored in the RAM.
Since processing will be delayed if it is determined whether the image pattern data is the same as the image pattern data already stored in RAM 161, normally each l vector in RAM 161 will not overlap the position of each l font in RAM (6). The data of each one-font image pattern received is sequentially stored in the RAM.
It needs to be stored in a writable location of +61, that is, in a location that is not used for display.

When displaying screen scrolling using the text method, R
The first vector to be output to A M +61 can be moved down or up one row or column at a time, but at this time, one row or one column that is no longer used for display in K, RAM +61 due to memory management. The portion storing image pattern data must always be cleared by writing blank pattern data.

In other words, the part that stores one row or one column that is no longer used for display in RAM +61 changes every time the screen display ends, and in this case, unless blank pattern data is written, the part that stores the next row or column that is no longer used for display changes. Since it is difficult to know where in RAM +61 to write image pattern data, memory management becomes extremely complicated.
It is necessary to always write a blank pattern to clear a part that is no longer used for the display of 161 and stores data of one row or one column of writable image patterns.

Note that if the first vector output from RAM (5) to RAM (61) cannot be changed,
It is sufficient to rewrite and transfer all the vectors in (5), but in this case, a blank pattern is also written in the part of RAM (6) that stores image pattern data for one row or column that is no longer needed. Must be written and cleared.

Also, when clearing the screen using the text method,
It is necessary to completely clear both LLAM (5) and +61.

In other words, even if you completely clear only A M (5),
The RAM (6
) may be addressed, so RAM (5
), it is necessary to completely clear RAM +61.

Therefore, when performing a screen scroll display using the text method, for example, it is necessary to clear blank pattern data by laminating it into the area where the data of the image pattern that is no longer used for the display of l'L A M +61 is stored. In this case, similar to the bitmap method, display processing can only be performed at low speed, and even with the text method, it is impossible to perform each display including screen clearing at high speed.

[Means for solving problems]

This invention sequentially receives data of each l unit image pattern formed by dividing a display screen into unit sections of characters and figures, together with data on the display position of the data, and processes the data of the received image pattern. In an image display device that updates the stored contents of a pattern I'LAM for pattern storage by storing it, and also reads the stored contents of the pattern RAM and displays an image, together with the patterns RA and M, each of the unit sections of the ELAM The text fLA whose reading is controlled by the reading control means is stored in the order of display to control the reading of the pattern RAM.
M, a list RAM that stores the writable address of the data of the image pattern in the pattern RAM, and a microcomputer, etc. 1. An image display device characterized by comprising a reception write control means for identifying a writeable position of image pattern data by referring to stored contents.

[For production]

Then, when updating the memory contents of the pattern RAM, 1
In order to identify the writable position of pattern RAM0 by referring to the list RAM, data of the received image pattern is transferred to pattern RAMK based on the above identification without clearing the writable position before updating the memory contents. It is possible to write and process data at very high speed.

〔Example〕

Next, this invention will be explained in detail with reference to FIGS. 1 to 7 showing one embodiment thereof.

FIG. 1 shows a display device that receives image pattern data of each 1 font and display position data obtained by reproducing the subcode of a CD-, and displays the image. This is a reception/write control unit consisting of a microcomputer, etc., which forms the reception/write control means, receives data obtained by reproduction, that is, transmission data, and generates various addresses, data, etc. necessary for writing. , address input/output terminal (a)
, are output from the data input/output terminal (d), respectively.

(9) is ■Hitachi model number HD 68458 CRT
This is a display control unit consisting of an integrated circuit for a controller, and forms a display control means, and is a display control unit (4) in FIG. 8(b).
Text address for displaying images in the same way as
In addition to outputting the raster address, the text address is varied by a scroll command output from the control section (8). Note that when there is no scroll command, the text address is not changed.

(b) is a text RAM similar to RAM (5) in FIG. di) to the control section (
8), the vector output from the input/output terminal (d) is input.

(2) is shown in Figure 8(b) (1:) RAM1617! :
Similarly O/< turn RAM, RAM II
The pattern memory address, that is, the vector, output from the data output terminal (dO) of O is connected to the address input terminal (a
i), and image pattern data output from the data input/output terminal (d) of the control section (8) is input to the data input terminal (di).

α→ is a signal conversion processing unit into which image pattern data of each 1 font outputted from the data output terminal (do) of fLAM (L5) is input, and the image pattern data is
R,G,B signals and video signals, vertical.

Convert to image signal consisting of horizontal synchronization signal and transmit to CRT-
output to a display means such as

The address input terminal (ai) of αG is the address input/output terminal (a) of the control unit (8).
The data input terminal ('') h and data output terminal (dO) are connected to the data input/output terminal (d) of the control section (8).

Note that the text memory address and vector outputted from the address input/output terminal (a) of the control unit (8) are outputted to the address input terminals (ai) of RAMQ□ and (to) via multiplexers 0υ and a3, respectively. Ru.

That is, writing to the RAM (IQ) is controlled by the control section (8)K, and reading from the RAM (IQ) is controlled by the control section (9).

Further, reading from RAM (2) is controlled by a vector of RAM (IG).

Furthermore, writing and reading of RAMQ5 are controlled by a control section (8).

By the way, you can get it by playing the subcode of a CD! The display screen is as shown in Fig. 2(a) (18th to 49th
(line) x (50 lines from 0th to 49th) font. In addition, the data of the 1 font image pattern is as follows:
For example, one section in the i-th row and j-th column (corresponds to i, ja).

And 1 font each (0, 0), CO, l),...
(1,0), (1゜1〕, ..., (r, J], ...
, (17, 49) are (vertical
Horizontal = ) 12x6 It is formed using dot image pattern data.

Therefore, data for each 1-font image pattern written in RAM (12) requires at least 12 x 6 pits corresponding to the 12 x 6 dots mentioned above.
Each vector written to O has RAM (18X5 of H).
A minimum of 10 bits are required to address each 7 ont of 0's.

It goes without saying that the vectors are written in EL A M (10) in the order of their display positions on the display screen.

Furthermore, RAMQ5 is provided to store each font that is no longer used for displaying ItAMQ3 and has become writable, and the writing and reading of RAMQ5 requires a minimum of @IO bits as well as vectors. is necessary.

In addition, in the following description, each 1-pector storage area of RAM (1 (1) will be referred to as a vector partition, and RAM.

The storage area for image pattern data for each 1 font of @ is called a font section, and the data stored in 几AM (to) corresponding to each font is called 1 list, and the storage area for each 1 font is called a font section. The area is called a list section.

In this embodiment, 12 bytes are allocated for writing and reading data for each 1 font image pattern.
2 for writing and reading each l vector and each list
Suppose we allocate bytes.

By the way, in order to store the data of the blank pattern of l font, the minimum memory capacity of AM (2) is larger than that of the summer display screen by the amount of data of l font.
Furthermore, in order to link and store the positions of writable fonts, RAMαG requires a storage capacity that is one font larger than the number of fonts on one display screen.

Therefore, the total capacity of RAM (1G, 02.αG) is at least the capacity to store 18X50 payp, as shown in Fig.
The capacity is set for storing 0+1 font image pattern data and the capacity for storing 18×50+1 lists, respectively. Note that (Fo) in the figure.

(So) indicates an extra 1 font section and 1 list section.

When the power is turned on, one font worth of blank pattern data for clearing is written into the extra one font section (Fo) of the RAM (Ll) under the write control of the control unit (8).

Next, when data for erasing the entire screen, that is, clearing the screen, obtained by playing a CD, for example, is transmitted to the control unit (8), the write control of the control unit (8) causes the data to be erased from the RAM (1G). One vector is written into the vector area each addressing a font area (FO) of the blank pattern.

Therefore, based on the text memory address of the control unit (9), when each l vector section of RAMII (I) is sequentially addressed, at this time, each l vector all addresses one font section (FO) and the To specify blank pattern data, the RAM is
g2 to the processing unit 114) of the blank pattern.
The data for one screen is output, and the screen is cleared.

When clearing the screen, instead of writing the blank pattern data into each 18x50 font section of AMQ3 as in the conventional text method,
Since it is only necessary to write the blank pattern data in one specific font block (FO), the screen can be cleared much faster than the text method, and at this time, the RAM (
2) The data in the 18x50 1 font section corresponding to the display screen is no longer used for display, and each of the 7 font sections becomes writable.

On the other hand, by clearing the screen, the section (FO) is removed (E
When the 18x50 font section of LAM (2) becomes writable, the write control of the control unit (9) causes the RAM Q9
The extra l list section (So
) is written as a starting point, and a list, that is, a link pointer, is written that links and sequentially specifies all the list sections in the RAM (to).

That is, a link pointer that addresses one of the 18×50 sections is written in the list section (SO), a link pointer that addresses the next section is written, and so on, and so on. The l list consisting of the last identifying nil code is written to the partition addressed by .

Since the 18x15'J block of RAMQ5 is arranged in the order of each font on the display screen, RAM (1
By addressing the list section (SO) of RAM Q5, all the linked list sections of fLAM Q5 are sequentially read, and from the link pointer of the list section of RAM Q5 read at this time, the write of fLAMQ3 is read out. It is now possible to identify font sections that can be loaded. The states of each fLAM (IG, (2), αG) when the screen is cleared are as shown in FIG. 4, with arrows indicating address positions.

Then, when the control unit (8) receives the image pattern of the l font, 9, for example, the character A, and the display position of the data, for example, Ci, j), the control unit (8) controls the reading of RAMnQ and writes the writable l of fLAM(2) based on the list of the list section of RAMnQ addressed by the list section (So).
A font section, for example (0,0), is identified, data of the received 1-font image pattern is written to the font section, and RAM
The display position of nQ (i, j': in the pecta section of ll,
Write the l vector addressing the font section (0,01) into which the data of the received image pattern has been written.

Furthermore, since the font section ((i), G) in which the data of the received image pattern has been written becomes write-inhibited, the control section (8) controls the RAM (II19) to write, and the RAM
The list section (0, 0
), for example, a link pointer specifying the writable list section (0, 2) is written to the list section (SO).

Therefore, when the control unit (9) reads out RAMrlG, the data of the 1-font image pattern in the RAM (the font section CD, l) of RAM (6) is read out by the vector of the vector section (i, j) of IQ). , the character A of the received image pattern is displayed at the position [;,, 3] on the display screen.
is displayed.

Furthermore, when the image pattern data of the next l font is received, the same operation as described above is performed, and at this time, 1 and the received image pattern data are written in the list area (So) of fLAMQ5. A link pointer corresponding to the specified font section is written.

Therefore, each time the data of the received 1-font image pattern is written, the RAM in which the data has been written is
The list section of RAM (to) corresponding to the font section in (2) is released from the address by the link pointer, and R
By reading AM (to), the control unit (8)
The writable font section of Qη can be identified.

In addition, the data of the received 1 font image pattern is
When writing to AM(2), the list section (S
The vector of the vector section of RAM αG specified by the link pointer of o) is the font section σ0 of RAMQ2)
When specifying , RAM (10, (2) is rewritten, but if the vector in the vector section of RAM n□ specifies a font section other than the font section (Fo), and a pattern other than a blank pattern is When it is determined that the image pattern data has already been written, R
AM(113, Qf9 is not rewritten.

Further, the state of each RAM II (1, (to), α$) when writing data of a 1-font image pattern is as shown in FIG.

Next, a case will be described in which, for example, one row of left scroll μ display is performed as one row or one column of scroll display.

Now, the letter A is displayed in the leftmost section of one scrolling line (hereinafter referred to as scroll line) on the display screen, and at this time, as shown in FIG. 6(a), RAM i(l
to the vector section of each column of the scroll row.

Assume that the vectors tI, tn, . .

In addition, in the scroll line, if characters are also displayed in each column after the character A, each vector from t1 to jn is also stored in the RAM.
(To) Specify each font section other than the font section (FO), and if nothing is displayed in each column after the letter A,
Each vector t1 to jn specifies a font section α0).

On the other hand, in the RAM (to), the list section corresponding to each font section in which the data of the image pattern of the column displaying the characters of the flow μ row is written is released from the address specification by the link pointer, and the diagonal line in the figure The list section corresponds to the font section of the image pattern data of the character A, and is freed from addressing by the link pointer.

Then, when data of a 1-font image pattern is received, the scrolling row of the display screen shifts by one section to the left, and the letter A is no longer displayed. By control, as shown in FIG. 6(b), the vectors of the vector section on the right side of the subject are sequentially written into each vector section of the scroll line of RAM (IQ), and the rightmost vector section is written with RAM. The vector specifying the font block (FO) in (2) is written, and the font block (FO) in which the data of the image pattern of character A is written.
k, l) are released from display.

Furthermore, since the font section (k, A') is released and becomes writable, the RAM is
The link pointer corresponding to the font block (k, l) is written in the fourth list block (SO), and the link pointer corresponding to the font block (k, l) is written in the block (SO).
k, l) link pointers are in the list area (SO).
This becomes the address of the next partition that was linked, and
The number of writable font sections in RAM (2) stored in G increases by one.

Thereafter, the same operation is repeated and each section of the scroll line of fLAM(2) is released from display in sequence, and the number of writable font sections stored in RAM Qf9 increases by one. do.

Then, RAM (IQ) is sequentially read out under the successive control of the control section (9) in the same manner as in the case of normal display, thereby performing one-line left-scrolling display.

Note that when the control unit (8) performs write control, the RA
M (IG vector is RAMQB font section (F
When specifying a font section that has already been released from display before writing, RAM (15) is not rewritten to prevent double storage.

As mentioned above, even when scrolling one row or one column, the RAM (g) is read out and the control unit (8)
In order to identify the font sections that have become writable in AMQa, it is not necessary to write blank pattern data to each font section that has become writable, and the RAM (
It is only necessary to rewrite the vector in 11), and high-speed processing can be performed.

Next, a description will be given of a screen scroll display in which the display screen is scrolled upward line by line.

In this case, first transfer the scroll command data to the control unit (
8) receives the scroll command, and the received scroll command is sent to the control unit (9).
is output to.

Then, by inputting a scroll command, the control section (9) scrolls and varies the readout address line by line, and lowers the subsequent address of RAMQG by one line each time one display is completed.

By the way, as mentioned above, one display screen is formed of 18x50 sections, so the RAM (
12)! Addressing an 8X50 font on a font-by-font basis requires a minimum of 210 bits, and the number of fonts addressed is greater than 18X50.

Therefore, when actually using a commercially available RAM, since RAM (10, 02, α9 has a capacity of a power of 2), for example, RAM (Lll is 1 used for display).
2” −+8X from the vector corresponding to 8×50 fonts
It has a vector partition that stores 50 more vectors.

As shown in FIG. 7(a), before the screen scroll display is performed, the RAMQ stores a vector block (for example, the character A) at the display address start position corresponding to the 0th row and Oth column of the display screen. The vector joo that specifies the font section (0, Ql) of RAM (2) is stored, and the vector section at the 0th row, 1st column, and the Oth row, nth column (n = 49) is stored in each row and 1st column. Vectors toe and ton specifying the font sections of data of the corresponding 1ijilψ pattern, for example data of characters B and C, are stored respectively, and vectors to, to+, -,
t・n, mu1・, tl,・-O,tan, conflict+−1—・
・1tIII・, E+al, ...-1tmn (m=+y
) are respectively memorized.

In addition, in each vector section in one row and one column below the vector section for one column in which vectors of radial ~tmn are stored, a vector jm+1 that specifies the address of a font section that is not used for display is stored.
6, tm+l 1 , . . . , tm+an are stored, respectively.

Under the read control of the control unit (9), first, each section from the section of vector t... at the display start position to the section of vector jmn is sequentially read out and the first screen display is performed.

Next, when the screen scroll command is received by the control unit (8), the control unit (8)
'1Write the vector addressing the font section (FO) of RAMQ2 to the vector section storing the vector tm++ o-tnv++ n of AMQO.

On the other hand, the control unit (9) lowers the start address position by one line and moves vector tn+kl from the section of vector j+a.
Sections up to n are sequentially read out, thereby displaying the second screen and scrolling the screen.

Also, under the write control of the control unit (8), the pecta to.

~ton Each font section stored in RAM Q
5, and each font section specified by pector too -s and -tea, that is, the font section in the top row that is no longer used for scroll display, can now be written. This is stored in RAM.

In addition, there is a font section (FO) in the vector tee-wt axis.
If there is a vector specifying the font section (Fo), the font section corresponding to the vector specifying the font section (Fo) is not written to the RAM α$, thereby preventing double writing.

Then, when data of a new image pattern for one line is received, the control unit (8) reads the list stored in the RAM Q5, identifies the writable section of the RAM (2), and writes the corresponding data. The image pattern data is sequentially written into the sections that can be written.

Therefore, even when the screen scrolls, 几AMQ
Since the control unit (8) reads ELAMQJO and identifies the font section that has become writable, there is no need to write blank pattern data to each font section that has become writable, allowing high-speed processing. .

Note that the states of each RAM (10, (2), cJB) before scrolling in the screen scroll display described above and after flow μ are as shown in FIGS. 7(a) and 7(b), respectively.

As explained above, in FIG. 1, the pattern ELAM (
), text RAM Q□, list RAM (
), and the address of the writable font section of RAMaa is linked and stored in the RAM (g), and the control unit (8) refers to the memory contents of the RAM (g) and stores ELA\(). 2) In order to identify the font section that has become writable and rewrite the AMQa based on the identification, each font section in RAM (2) is blanked, even when the screen is cleared or the screen is scrolled. Rather than writing and clearing pattern data, the RA
It is only necessary to change the memory contents of M+10, and when displaying in any display method, the conventional bitmap method can be used.

It can be done much better than the pattern method.

In fact, when the display screen is divided into (vertical x horizontal) = 18 x 50 sections and 1 font is 12 bytes, the number of bytes for writing and reading required to clear the screen is 10,800 bits in the bitmap method and text method. Compared to becoming
In FIG. 1, it can be seen that only 3600 bytes are required and the process can be performed at high speed.

In addition, as mentioned above! ! In the example, each RAM (IQ, (2), α4) was provided separately, but in reality, the storage capacity of each RAM (IQ, (2), (to)) is For example, RAM (6
) It is also possible to form pRAMQf9 in the remaining memory area of the controller (8). In this case, as shown by the broken line in FIG. ) data input/output terminal (d) K connection.

〔Effect of the invention〕

Therefore, according to the image display device of the present invention, instead of storing a predefined image pattern, the control section (8) serving as the reception/writing control means stores the pattern RAM (6) based on the data of the received image pattern. In addition to updating the memory contents of the pattern RAM (to), when reading out the pattern RAM (to) and displaying an image, by providing a text RAM (Ll, Suxto RAMQ5) together with the pattern RAM Qa, the data stored in the RAM (Ll9) can be updated. Writable R
It is possible to identify the position of AM (2) and write the received image pattern data into the RAM Q2, and in particular, screen clearing, scrolling display, etc. can be performed at very high speed.

[Brief explanation of drawings]

FIGS. M1 to 7 show one embodiment of the image display device of the present invention, FIG. 1 is a block diagram, and FIGS. 2(a), (
b) is a display screen, an explanatory diagram of one section of the screen, and Fig. 3(a)
), (b), (C) are text RAM +,
Pattern fLAl (Lith) Minimum RAM capacity explanation diagram. Figure 4 is an explanation diagram of each RAM when clearing the screen. Figure 5 is an explanation diagram of each RAM when data of an image pattern of 1 unit section is written. Explanatory diagram, Figure 6 (a) and (b) are 1
FIG. 7(a) is an explanatory diagram of each RAM before and after scrolling rows. (b) shows each RAM before and after screen scroll display.
FIG. 8 is a block diagram of a conventional bitmap type and text type image display device.

Claims (1)

[Claims] (1) Sequentially receive the data of each I-unit image pattern formed by dividing the display screen into unit sections of characters and figures, together with the data of the display position of the data, and store the data of the received image pattern. In an image display device that updates the storage contents of a pattern RAM for pattern storage and reads out the storage contents of the pattern RAM to display an image, the RAM as well as the pattern RAM
Addresses for each of the unit sections of M are stored in display order to control readout of the pattern RAM, and a text RAM whose readout is controlled by a readout control means, and an address in which data of the image pattern in the pattern RAM can be written. A reception write is made up of a list RAM for storing image pattern data, and a microcomputer, etc., and refers to the storage contents of the list RAM when updating the storage contents of the pattern RAM, and identifies a writable position of image pattern data. An image display device comprising a control means.