JPH03237491A - Font memory controller - Google Patents

Abstract

PURPOSE:To rapidly obtain font data by assigning the same address space to font memories with plural dot constitutions and aligning the reference positions of the font data of th font memories. CONSTITUTION:This font memory controller is provided with the plural font memories 35 and 36 in which the font data different in the dot constitutions is stored and for which the address of the same address space is assigned, and a controller 32 which generates selective data for selecting either font memory corresponding to the dot constitution to be outputted based on the data inputted from a host device and a reading address for reading the font data from the font memories. As for the memories 35 and 36, their capacities are the same and the font data corresponding to the same character code is stored the same address. The reading address 45 commonly used for both font memories is generated by the controller 32. Thus, without conscious of the dot constitutions, the font data with either dot constitution can be easily obtained by the controller 32.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a font memory control device that controls access to a font memory.

(Prior Art) When printing or displaying on a printing device, display device, etc., a predetermined dot configuration (for example, one character is 16x1
Image data of 6.256 dots or 24 x 24 = 576 dots is used. This image data is generally obtained by reading the contents of a font memory. This font memory is composed of a ROM or the like in which image data indicating predetermined characters, symbols, etc., that is, font data is stored in advance. The process of accessing this font memory to obtain desired font data is performed by the font memory control device.

Here, how printing or display is performed on a printing device, a display device, etc., that is, the operation of a conventional font memory control device will be explained.

FIG. 2 shows an explanatory diagram of a conventional font memory control device.

In the figure, a host device 11 and a terminal device 12 are shown.

The host device 11 is composed of a microcomputer device etc. equipped with a keyboard, a storage device, etc. for executing various information processing and the like. The terminal device 12 is a device that outputs characters, ie, a printing device, a display device, and the like. Here, the discussion will proceed assuming that the printer is a printing device.

The host device 11 includes a CPU 1. A storage device 2 and a keyboard 3 are provided. The CPUI is a processor or the like that controls each part constituting the host device 11. The storage device 2 is composed of a RAM and the like that stores programs, data, etc. necessary for the operation of the CPU 1. keyboard 3
is used to input various information.

The terminal device 12 is provided with a controller 5, a character output section 6, and a storage device section 7. Here, the font memory control device is composed of a controller 5 and a storage unit 7.

The controller 5 is a processor or the like that executes various processes according to instructions from the host device 11. The character output unit 6 outputs characters, that is, prints and displays characters. For example, in the case of a printing device, the character output unit 6 includes a print head, a platen, etc., and a display screen. Storage unit 7
The controller 5 is made up of a RAM, a ROM, etc. that store programs, data, etc. necessary for the operation of the controller 5.

This storage unit 7 is provided with a code conversion table 22 and a font memory 23. Font memory 23
are the font memory 23a and the font memory 23b.
It consists of The code conversion table 22 is provided in a RAM or the like of the storage unit 7, and similarly, the phono 1 memory 23 is provided in a ROM or the like.

The code conversion table 22 is a table that is referred to when obtaining an address for accessing the font memory 23. The font memory 23 has a predetermined dot configuration,
For example, it stores font data (character data) in which one character consists of +6XI6 dots, 24X24 dots, etc.

Here, the font memory B stores 24x24 dot configuration font data, and the font memory B stores +6x font data.
Assume that font data with a dot structure of I6 is stored.

Here, the storage device section 7 will be explained using FIG.

FIG. 3 is a conceptual diagram of the conventional storage device section 7. As shown in FIG.

The figure shows the configuration of the code conversion table 22 and the address map 20 of the storage unit 7.

First, as shown in the address map 20, the address structure of the storage unit 7 includes a main memory (work area) 2l for storing data received from the host device 11, a code conversion table 22, a font memory 23a, and a font memory B. 23b, and then a reference area 24 storing an IPL (initial program loader) and the like. Address spaces are allocated in this order.

Now, the code conversion table 22 includes a first item 22a in which search data a" and search data f (DATAa-DATAf) are stored, and a font memory 23a and a font B memory 23b corresponding to each of these addresses. A second item 22b is provided in which the address to be accessed, ie the read address mill read address f (RADa=RADf), is stored.

The first half of the code conversion table 22 is a B font memory code conversion table 25a that is used when accessing the B font memory 23a, and the second half is a B font memory code conversion table 25a that is used when accessing the B font memory 23b. This is a font memory code conversion table 25b.

Now, returning to FIG. 2, the operation of the conventional font memory control device will be explained.

In the figure, data handled by the host device 11 and the terminal device 12 is shown in the data stream 30 item.

First, when it becomes necessary to output a character using the terminal device 12, the CPU 1 of the host device 11 generates a type code 13 that specifies the dot configuration of the character to be output, and a type code 13 that specifies the dot configuration of the character to be output. Once the character code 14 that specifies the character is generated and transferred to the terminal device 12, the controller 5 of the terminal device 12 receives the type code 13 and the character code 14, and generates, for example, 2-byte data indicating the contents of both. Perform processing to obtain . The controller 5 retrieves the data obtained through this process (search data: DATA>15
Based on this, the code conversion table 22 is searched. As a result, a match with the data stored in a predetermined item of the first item 22a of the code conversion table 22 is obtained. The controller 5 selects the item content for which this match has been obtained, that is, the second item content.
Contents of item 22b (read address/RAD)
It will read l7. The controller 5 accesses the font memory 23 based on this read address 17 to obtain character data (font data) 19 corresponding to the type code 13 and character code 14 previously received from the host device 11. I can do it. The controller 5 outputs this character data 19 to the character output section 6 to perform predetermined printing.

(Problem to be Solved by the Invention) By the way, in the font memory control device having the above configuration, the font memory 23a and the B font memory 23b are arranged in separate address spaces, so the controller 5 , a process is performed to calculate the read address 17 based on both the type code 13 and the character code 14.

This has caused the following problems.

First, when the font memory 23 is composed of a large number of font memories with different dot configurations, the code conversion table 22 also includes each font data 19 of the font memory 23.
In order to cover all the read addresses 17 corresponding to , the number of items increases. Therefore, the proportion of the address space of the storage unit 7 occupied by the code conversion table 22 and the font memory 23 increases, but the work area 2
There is a limit to how much the area of 1 and the reference area 24 can be removed. As a result, there is a limit to the number of font memories with different dot configurations that can be prepared, and a problem arises in that it is not possible to handle the output of a large number of font data 19 with different dot configurations. Furthermore, as the number of items in the code conversion table 22 increases, the time required for searching using the search data 15 becomes longer, creating a problem that it is difficult to obtain the font data 19 quickly.

The present invention has been made with attention to the above points, and an object of the present invention is to provide a font memory control device that can quickly obtain a large number of font data having different dot configurations.

(Means for Solving the Problems) A font memory control device of the present invention has a plurality of font memories each storing font data having different dot configurations and to which addresses in the same address space are assigned, and input from a host device. , control data for selecting any font memory corresponding to the dot configuration to be output based on data including a type code and character code specifying the dot configuration, and reading the font data from the font memory. a controller that generates a read address; each of the font memories stores font data having the same capacity and corresponding to the same character code at the same address; and the controller stores the font data common to all the font memories. It generates a read address.

(Function) The above device has multiple font memories that each store font data with different dot configurations and are assigned addresses in the same address space, and determines the dot configuration to be output based on data input from the host device. A controller is prepared that generates selection data for selecting one of the corresponding font memories and a read address for reading font data from the font memory. Each font memory has the same capacity and stores font data corresponding to the same character code at the same address. The controller then generates a common read address for all font memories. Thereby, the controller can easily obtain font data for each dot configuration without being aware of the dot configuration.

(Embodiment) FIG. 1 is a block diagram of a font memory control device of the present invention.

As shown in the figure, a font memory control device 50 of the present invention
is composed of a controller 32, a selector circuit 33, and a storage unit 34. The storage unit 34 includes a B font memory 35, a B font memory 36, a RAM 37,
A ROM 38 is provided.

The controller 32 is connected to a selector circuit 33 and a storage unit 34. Further, the output side of the selector circuit 33 is connected to a B font memory 35 and a B font memory 36.

The controller 32 receives data 3 consisting of a type code 13 and a character code 14 from the host device 11 (same as in FIG. 2).
1, and outputs a selection address 41 and control data 42 to the selector circuit 33, and a read address 45 to the font memory 35 and B font memory 36. When the selector circuit 33 receives the selection address 41, it accepts the control data 42, and based on the contents of the control data 42,
It consists of a decoder and the like that output selection signals 43 and 44 to the B font memory 35 or the B font memory 36. The B font memory 35 and the B font memory 36 are each composed of a ROM or the like to which the same address space within the address space of the storage unit 34 is allocated. These font memories become effective when the selection signal from the selector circuit 33 is set to a low level, for example, and form a part of the address space of the storage unit 34. That is, assuming that the font memory 35 is the first bank and the font memory B is the second bank, the bank to be read, that is, the font memory, is selected by appropriately switching banks using the selection signals 43 and 44. I can do it. Note that the B font memory 35 and the B font memory 36 have the same storage capacity.

The RAM 37 is the work area 2 previously explained in FIG.
This falls under 1. The ROM 38 corresponds to the reference area 24 described above in FIG. 3, and the controller 32 executes these accesses via the control line 47.

Font data 46 is output from the B font memory 35 and the B font memory 36 to a character output section (not shown).

Here, the configuration of the storage device section 34 according to the present invention will be explained using FIG. 4.

FIG. 4 is a conceptual diagram of the storage unit 34 according to the present invention.

The figure shows an address map 60 of the storage unit 34, and detailed address maps of the font memory 35 and the font B memory 36.

First, as shown in the address map 60, the address structure of the storage unit 34 is as follows: a main memory (work area) 61 for storing data received from the host device 11, a font memory area 62, an IPL (initial program loader), etc. Address spaces are allocated in the order of the reference areas 63 that have been assigned.

Here, the address of the font memory area 62 is ADH,
~ADRn, then font memory 35 and B
Each address of the font memory 36 is also A.D.
Rl” A D Rn.

The font memory 35 has a 24x24 dot configuration, and the B font memory 36 has a 16x16 dot configuration, so the storage capacity per character (1 font data) is 72 bytes in the font memory 35. , B font memory 36, it is 32 bytes.

In order to align the storage positions of the beginning of each font data, that is, a portion of font data indicating one character, in both the A font memory 35 and the B font memory 36, 40 bytes of dummy data (
For example, '0'')65, etc. are stored, and the storage capacity required for one character is set to 72 bytes.

Specifically, the beginning of the font memory 35 (address A
Store the font data ■ in the address ADH
,+72 bytes, that is, address ADR, stores font data ■.

As for the B font memory 36, similarly to the font memory 35, it is assumed that the font data ■' is stored at the beginning (address ^DR,). Here, since the font data ■' is 32 bytes, the address ADH,
+ Stores 32 bytes, that is, 40 bytes of dummy data 65 starting from address ADH. Then, similarly to the font memory 35, the address ADR, + 32 bytes + 4
Font data ■' in 0 byte, that is, address ADH
will be stored.

It should be noted that the font data ■ and the font data ■', and the font data ■ and the font data ■' have the same content except that the dot configurations are different. For example, if the font data {circle over (2)} is font data representing the character "A" having a 24×24 dot structure, the font data {circle around (2)] is font data representing the character "A" having a 16×I6 dot structure.

Now, returning to FIG. 1, the operation of the font memory control device 50 of the present invention will be described.

First, upon receiving data 31 consisting of the type code 13 and character code 14, the controller 32 outputs control data 42 based on the type code 13 to the selector circuit 33 along with a selection address 41 for activating the selector circuit 33. . The selector circuit 33 selects the selected address 41
The control data 42 is recognized as having been activated by
Perform the analysis. For example, if the control data indicates "O", enable the selection signal 43 and set the control data to "1".
If so, the selection signal 44 is enabled.

Here, since the type code 13 requests character output in a 24x24 dot configuration, the selection signal 43 is
is set to valid.

On the other hand, after outputting the control data 42, the controller 32 generates and outputs a read address 45 (for example, ADH+) based on the character code 14 to the B font memory 35 and the B font memory 36. This generation is performed by simply decoding the character code 14.

As a result, the font data 46 in the area indicated by the read address 45 is read from the font memory 35 to which the selection signal 43 is set to be valid. B font memory 3
No. 6 is never accessed because the selection signal 44 indicates invalidity.

Similarly, when the type code 13 requests the output of characters in a 16XI6 dot configuration, the selector circuit 33 sets the selection signal 44 to valid. Therefore, read address 45 from B font memory 36 (A
The font data 46 in the area indicated by DH+) is read out.

As described above, the font memory control device of the present invention sets each font memory having a different dot configuration to a valid state in which reading is possible, and uses the same read address for the same character code.

The present invention is not limited to the above embodiments.

The number of font memories is 24x24 dot configuration, 16x
Although two of the 16 dot configurations have been described as examples, the number of font memories and the dot configuration are not particularly limited. Note that the capacity of the font memory is set according to the size of the dot configuration. For example, if you prepare a font memory with a 32x32 dot configuration to deal with three dot configurations, you will need font memory 3 with a 24x24 dot configuration.
5 is 56 bytes per 1 font data, and the B font memory 36 having a 16XI6 dot configuration stores 96 bytes of dummy data per 1 font data.

In addition, by making the font memory easily removable, for example, each user can select the font memory to be installed as appropriate, and from the case where only one font memory is installed to the case where many font memories are installed. It is possible to configure a font memory control device with a wide range of applications.

(Effects of the Invention) The font data control device of the present invention configured as described above allocates the same address space to a plurality of dot-configured font memories, and the reference positions of font data in each font memory are aligned. There is no need to calculate a read address for each font memory. Therefore, the limited address space can be used effectively, and font data can be obtained quickly because the processing time required for calculating read addresses and the like is not prolonged.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a font memory control device according to the present invention, FIG. 2 is an explanatory diagram of a conventional font memory control device, FIG. 3 is a conceptual diagram of a conventional storage unit, and FIG. 4 is a diagram according to the present invention. FIG. 3 is a conceptual diagram of a storage unit. 32... Controller, 33... Selector circuit, 3
4... Storage unit, 35... Font memory, 3
6...B font memory.

Claims (1)

[Claims] Storing font data each having a different dot configuration,
and a plurality of font memories to which addresses in the same address space are assigned, and one of the font memories corresponding to the dot configuration to be output based on data including a type code and character code that specify the dot configuration input from the host device. The font memory includes control data for selecting a font memory, and a controller for generating a read address for reading the font data from the font memory, and each of the font memories has the same capacity and all fonts corresponding to the same character code. A font memory control device, wherein data is stored at the same address, and the controller generates the read address common to all the font memories.