JPH05173531A - Font memory device - Google Patents

Abstract

PURPOSE:To reduce the number of accessing times from a CPU and to shorten time until developing font data in a memory for an image. CONSTITUTION:When a font code is inputted from the CPU 11, the address of a font-data memory 13 is generated in a font code conversion table memory 12, and some lines of the font data of the memory 13 are outputted to the memory for the image 15 in every scanning line by using a font data output control device 14 in accordance with the address. Therefore, the font data is consecutively transferred at high speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a font memory device for storing font data indicating fonts such as characters and symbols to be displayed on a display device.

[0002]

2. Description of the Related Art FIG. 2 is a block diagram showing a configuration of a conventional font memory device and its peripheral devices. In FIG. 2, reference numeral 21 denotes a CPU (central processing unit) that performs image processing,
Reference numeral 25 is a font data memory 23 for storing font data indicating fonts such as characters and symbols, and a font data memory 23 for storing font codes input from the outside (CPU 21).
A font memory device composed of a font code conversion table memory 22 for converting to a different address, and 24 is an image for storing image data indicating the characters and symbols to be displayed by expanding the font data from the font data memory 23. For memory.

Next, the operation will be described. The font code sent from the CPU 21 is converted into an address in the font data memory 23 where the corresponding font data is stored, using the font code conversion table memory 22. Next, the CPU 21 accesses the font data memory 23 based on the address converted by the font code conversion table memory 22, reads the font data, and expands the image data in the image memory 24.

[0004]

Since the conventional font memory device is constructed as described above, the CPU 21
It is necessary to once convert the font code from the font code into the address of the font data in the font code conversion table memory 22, and it is necessary to output the address to the font data memory 23 a plurality of times for each scanning line for reading and read the font data. Therefore, a lot of time is required until the font data is expanded in the image memory 24, and there is a problem that it is impossible to speed up the processing.

The present invention has been made to solve the above problems, and a font memory device capable of reducing the number of accesses from the CPU and shortening the time until the font data is expanded in the image memory. The purpose is to provide.

[0006]

A font memory device according to the present invention includes a font data memory 13 for storing font data indicating fonts such as characters and symbols, and an external (CP
U11) A font code conversion table memory 12 for converting the font code input from U11) into an address of the font data memory 13, and a line for each scanning line of reading according to the address of the font data obtained in this font code conversion table memory 12. The font data output controller 14 reads out several minutes of font data from the font data memory 13 and outputs it to the outside (image memory 15), and each component is formed on a single semiconductor substrate.

[0007]

When a font code is input from the outside, an address of the font data memory 13 is generated in the font code conversion table memory 12, and the font data of the font data memory 13 is sent to the outside by the font data output controller 14 according to this address. The number of rows is output for each scanning line for reading.

[0008]

1 is a block diagram showing the configuration of a font memory device and its peripheral devices according to an embodiment of the present invention. In FIG. 1, 11 is a CPU for performing image processing and the like, 1
Reference numeral 6 is a font memory device of this embodiment, and reference numeral 15 is an image memory for storing the image data indicating the characters and symbols to be displayed by expanding the font data from the font memory device 13. The font memory device 16 of this embodiment
Is a font data memory 13 that stores font data indicating fonts such as characters and symbols, and a font data memory 13 that stores font codes input from the outside (CPU 11).
Of the font code conversion table memory 12 for converting into the address of the font data, and the font data for the number of lines for each scanning line read from the font data memory 13 according to the address of the font data obtained in the font code conversion table memory 12. External (image memory 1
5) and a font data output control device 14 for outputting to 5).

Next, the operation will be described. When a font code is input from the CPU 11, the font memory device 16 uses a font code conversion table memory 12 to generate a font data memory 13 corresponding to the font code.
The font data is output from the font data memory 13 in accordance with the converted address, the font data is transferred to the font data output controller 14 for each scanning line for reading, and is output to the image memory 15. To do. By repeating the processing in the font memory device 16 for the number of lines of the font data, the expansion processing of the font data in the image memory 15 is completed.

According to the above embodiment, since the font data output control device is provided, the CPU can read the font data from the font data memory by simply outputting the font code. Access the font code conversion table memory,
Furthermore, compared to accessing the font data memory, the number of accesses to the font data memory is reduced, and the load of the CPU's program processing can be reduced.
It is possible to develop font data in the image memory at high speed and continuously. Further, if the font data memory, the font code conversion table memory and the font data output control device in the above embodiment are formed on a single semiconductor substrate, the circuit mounting area is reduced.

[0011]

As described above, according to the present invention, the font data corresponding to the number of lines for each scanning line is read from the font data memory according to the address of the font data obtained in the font code conversion table memory, and is output to the outside. Since it is configured with a data output control device, C
The number of times of access from the PU can be reduced, which can reduce the load of program processing, and can shorten the time until the font data is expanded in the image memory, so that the font data can be transferred at high speed and continuously. The effect is obtained. Further, according to the present invention, since each constituent element is formed on a single semiconductor substrate, there is an effect that the circuit mounting area is reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a font memory device and its peripheral devices according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a conventional font memory device and its peripheral device.

[Explanation of symbols]

 12 font code conversion table memory 13 font data memory 14 font data output control device 16 font memory device

Claims (1)

[Claims] 1. A font memory device having a font data memory for storing font data indicating fonts such as characters and symbols, and font code conversion for converting a font code input from the outside into an address of the font data memory. A table memory and a font data output control device for reading the font data of the number of lines for each scanning line read out from the font data memory according to the address of the font data obtained in the font code conversion table memory and outputting it to the outside. A font memory device characterized in that each of the above components is formed on a single semiconductor substrate.