JPS6048072A - Desk top computer with kanji function - 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 [Field of Application of the Invention] The present invention relates to a desktop computer with a kanji function, and more particularly to a desktop computer with a kanji function that has an improved implementation method for a kanji ROM.

[Background of the invention]

In a desktop computer with a kanji function, when displaying kanji on a CRT, the display pattern of the kanji is stored in the kanji ROM (according to a program, the microprocessor reads the display pattern from the kanji ROM, writes it to the RAMK for the CRT, Based on this C
It is displayed on RT.

In a conventional desktop computer with a kanji function, as shown in FIG. In particular, when realizing JIS 1st level and J Engineering S 2nd level, each kanji ROM1.2 should be
As shown in the figure, the kanji ROM1.2 is located at separate addresses a and b.However, since the Kanji ROM1.2 has a large capacity, it occupies a large amount of the microprocessor's address space and is not required for desktop computers. Another method is to read the display pattern of kanji from an external storage device such as a cassette deck or 70TB disk and write it into the microprocessor's RAM. There is also a method of using this method, but it has the disadvantage that the processing speed is slow because it uses an external storage device.

[Purpose of the invention]

The object of the present invention is to provide a desktop with a kanji function that is efficiently implemented by arranging kanji display patterns in the address space of a microprocessor as a kanji ROM and reducing memory addresses, rather than storing them in an external storage device. The purpose is to provide computers.

[Summary of the invention]

The desktop computer with kanji function of the present invention is equipped with a microprocessor, a CRT for displaying kanji, and two kanji ROMs that store kanji display patterns. The device is arranged in an address space and is characterized by having means for switching the readout of the first Kanji ROM and the second Kanji ROM in a page format based on instructions from the microprocessor.

[Embodiments of the invention]

The present invention will be described in more detail below with reference to embodiments shown in the accompanying drawings.

FIG. 3 is a diagram showing one embodiment of the present invention, and the same parts as in FIG.
Figure 4 shows the kanji ROMI shown in Figure 3.

2 is a diagram showing a memory map of No. 2. FIG.

The kanji ROM1 shown in FIG. 3 corresponds to the J Engineering S first level, and the kanji ROM2 corresponds to the 51st second level. This Kanji ROM 1.2 is placed at address C in the memory map shown in FIG. 4, and is connected to AND circuit 4.
5 and switches between Kanji ROM1 and Kanji ROM2.

In other words, between JIS 1st level and J Engineering S 2nd level, J Engineering S
Since the first level is used more frequently, the output wind of latch 6 is assigned to Kanji ROM1 (because it becomes 1 when latch 3 is reset), and the selection signal S1 of Kanji ROM1.2 and the above output Q are assigned. Take the logical sum with AND circuit 4, Kanji RO
Operate M1.

To operate the Kanji ROM2, first input and set the input DK@1 of the Latte 3, which causes the Kanji ROM2 to operate until the latch 6 is reset.Since the latch 3 is 1 bit, , it is sufficient to allocate the address d at the first location. Therefore, according to this method, the address of the kanji ROM corresponding to the second level of J Engineering S is unnecessary, and the RAM can be increased by that amount or allocated for other purposes. can be done.

As another application, by further dividing the Kanji ROM 1.2 into several pages, even a low-end microprocessor with a small memory address space can handle Kanji.

Furthermore, by allocating kanji with different patterns to separate pages, multiple types of 7-onts can be handled.

Such an operation can be realized by inputting a page switching latch selection signal to the latch 30 input OK shown in FIG.

〔Effect of the invention〕

According to the present invention, the memory address space of a microprocessor can be used efficiently, and the RAM capacity can be increased by the amount saved, thereby significantly improving the performance of a desktop computer with a kanji function. I can do it. Further, even if the second page and subsequent pages are made optional, the efficiency of using the memory address space remains the same even if the second and subsequent pages are not available.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the implementation state of a conventional kanji ROM, FIG. 2 is a diagram showing a conventional memory map, and FIG. 3 is a block diagram showing the implementation state of the kanji ROM in a desktop computer with a kanji function of the present invention. FIG. 4 is a diagram showing an example of a memory map according to the present invention. 1, 2... Kanji ROM, 3... Latch, 4.5...
・AND circuit No. 112] (A8) CDB) 73 Figure 2: $4 Figure

Claims (1)

[Claims] In a desktop computer equipped with a microprocessor, a CRT that displays kanji, and two kanji ROMs that store kanji display patterns, the first kanji ROM and the second kanji ROM are placed in the same address space of the microprocessor, and the 1. A desktop computer with a kanji function, characterized in that it is provided with means for switching reading of a first kanji ROM and a second kanji ROM based on an instruction from a microprocessor.