JPH08339269A - External storage device for computer - Google Patents

Abstract

PURPOSE: To provide an access mechanism to a ROM in which compressed data and programs coexist so as to store the compressed data and the programs in the same ROM by providing a ROM selection mechanism and a transmission read mechanism in a data processing mechanism. CONSTITUTION: In the data processing mechanism 13 of this external storage device 1, at the time of reading the compressed data, an address on the ROM 2 is generated in a compressed data ROM address generation mechanism 4. While a CPU 7 does not generate the address of the ROM 2, a data expansion mechanism 3 directly reads the compressed data of the ROM 2 through a ROM interface block 14 by the address generated in the compressed data ROM address generation mechanism 4. However, when the CPU 7 generates the address of the ROM 2, the address bus switching mechanism 18 and the data bus switching mechanism 19 of the transmission read mechanism 16 switch a bus to the side of a CPU I/F block 15 and the programs and data are outputted to the CPU 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an external storage device used in a computer game machine using a non-volatile semiconductor memory such as a ROM cartridge.

[0002]

2. Description of the Related Art The basic structure of a home computer game machine is a device for inputting data, a device for outputting data, and a computer main body, as in a general computer. The external storage device of the home-use game machine is a CD-R
OM and ROM cartridges are used. These are sold for each game software.

For example, a ROM mounted in an external storage device cannot be written, but a general external storage device has a writable memory (RAM) having a battery backup mechanism as shown in FIG. It is built in, and is devised so that it can memorize the state in the middle of the game and the password for each player.

FIG. 3 shows an example of the basic hardware configuration of the main body of a home-use game machine. CPU is a central processing unit,
It is the core of the game console. The programs and data stored in the external storage device are subjected to processing such as program execution, data processing, and transfer by CPU analysis. Image data read from an external storage device or image data created by a program is sent to a VDC (video display controller) and processed (defined) into image data that can be displayed on a display.

Data processed by VDC is temporarily stored in VRAM. The data defined by VDC and stored in the VRAM is divided into background (background image) and sprite (protagonist of motion, etc.), and information such as its display pattern, display position on the display, and display color is added.

A VCE (video color encoder) converts a digital color image signal sent from VDC through a video output port into a CRT analog RGB signal and a video color signal based on color palette information stored in the VCE. , Output to an external video device.

On the other hand, sound information such as music and onomatopoeia analyzed by the CPU is a sound effect integrated with an image by a function of a stereo circuit configuration, a noise generation circuit, a low frequency generation circuit, etc. by a PSG (program sound generator). Is output to the speaker.

In many cases, a computer game machine handles image data including an animation or a photograph. In particular, games incorporating movie images and video natural images have recently come into the limelight. Image data, unlike text data, requires a large amount of memory. The closer it is to a natural picture, the more memory it requires. Also, animations are becoming more multicolored and more precise.

The finer the image to be handled and the more colors it has, the larger the image data amount becomes. Therefore, the external storage device that provides the game is required to be a large-capacity storage medium. However, since increasing the capacity of the storage medium increases the cost, it is difficult to simply apply the same to a home-use game machine that requires low cost.
Therefore, a commonly used method is data compression. There are various methods for compressing data.

By compressing the data, the memory capacity of the external storage medium for recording the data can be saved, but the compressed data cannot be used as it is. When the computer game machine reads the compressed data, it must revert to the original format of the data. This "returning to the original data" is called data decompression, and in a conventional home computer game machine using an external storage device, this data decompression is performed by the CPU of the game machine body.

FIG. 4 is an explanatory diagram of a computer game machine using an external storage device as the external storage device. The image control means 9 corresponds to VDC, VCE and VRAM in FIG.
The voice control means 10 corresponds to the PSG in FIG. ROM2
The program and data are stored in. When the power is turned on, the CPU 7 starts reading the program from a certain fixed address on the ROM 2 and analyzes and executes the program according to the logic of the program.

When there is a data read command in the program, the CPU 7 reads the data in the ROM 2 and RA
The data is expanded to M8, or depending on the type of data, the data is directly transferred to the image control means or the audio control means. Of course, the image control means and the voice control means also operate under the control of the CPU 7.

[0013]

In the conventional computer game machine, if the data in the external storage device contains compressed data, it cannot be used even if it is sent directly to the image control means 9 or the audio control means 10. First, the compressed data is once read into the RAM 8 and then decompressed by the CPU 7 to restore the original raw data. With such compressed data, the CPU 7 had to spend processing time to decompress the data.

FIG. 5 is a system configuration diagram using a ROM cassette incorporating a dedicated compression data decompression mechanism. The ROM 12 that stores data is connected to the CPU via the compressed data decompression mechanism. On the other hand, the ROM 11 storing the program is directly connected to the CPU. Further, FIG. 6 shows the RO when the system configuration of FIG.
It is explanatory drawing of M structure. ROM is ROM1 that stores data, ROM that stores programs is ROM
It is configured separately from 2.

In a conventional computer game machine, decompression of compressed data is performed by software. What is done by software means that the CPU of the game machine body decompresses the compressed data, and the load on the CPU is heavy. As a result, when the data decompression takes a long time, there arises a problem that the screen and the sound are temporarily stopped during the game. Therefore, there are many restrictions on the use of a complicated algorithm having a high compression rate.

At present, in computer game machines, the scale of programs and data for games is increasing along with the improvement in performance. In a cassette using a ROM as a software providing medium, in order to solve the above-mentioned problems, data compression is dealt with for increasing data, and a dedicated compression is applied to the problem that it takes time to decompress compressed data. It may be possible to solve the problem by providing a data decompression mechanism.

However, in a system using a dedicated compressed data decompression mechanism, normally, when decompressing the compressed data, the ROM storing the compressed data needs to transfer the data to the compressed data decompression mechanism. However, since the CPU is executing the program, the ROM storing the compressed data could not be connected to the bus of the CPU. This enables compressed data storage ROM and program storage ROM.
Another problem arises in that the two must be separated. The ROM1 and ROM2 in FIG. 6 are used for this reason.

It is an object of the present invention to develop an access mechanism to a ROM in which compressed data and a program coexist so that the compressed data and the program can be stored in the same ROM.

[0019]

The external storage device of the conventional computer game machine is merely a medium for storing data. For this reason, the CPU has to perform a series of data input processing from reading of compressed data to decompression / transfer. To solve this problem, in a system in which compressed data can be decompressed by hardware, the data ROM and the program ROM must be separate ROMs.

In the above system, the compressed data and the program cannot be stored in the same recording medium because the compressed data decompression mechanism reads the compressed data during decompression of the compressed data.
This is because the bus cannot be shared because it conflicts with the PU program execution. As a result, it was necessary to store the compressed data in a ROM different from the program and read each ROM by another route.

According to the present invention, a transparent reading mechanism for outputting a program and compressed data on the same ROM to the CPU and the compressed data decompression mechanism, and an RO for selecting the ROM configuration.
An M configuration selection mechanism was provided for the data processing function. If these mechanisms are provided in the data processing function, even if the compressed data and the program are in the same ROM or in a different ROM, the same handling as in the case of the conventional uncompressed data and the program can be performed. .

[0022]

As an embodiment of the present invention, an RO in which compressed data and a program (non-compressed data) as shown in FIG. 1 are mixed.
A system using an external storage device having a transparent read-out mechanism which is a mechanism capable of reading data on M and a data processing mechanism having a built-in ROM configuration selecting mechanism for selecting a ROM configuration will be described. The external storage device 1 includes a ROM 2 and a data processing mechanism 13. The data processing mechanism 13 includes a ROM bank switching mechanism 5, a ROM interface block 14, a CPU interface block 15, a compressed data decompression mechanism 3, and a compressed data ROM address generation mechanism. 4, a transparent reading mechanism 16, an address converting mechanism 17, an address switching mechanism 18, a data bus switching mechanism 19, and a ROM configuration selecting mechanism 20. Further, 6 is a main body of a game machine for home use, and 7 is a CPU.
The presence or absence of the program storing ROM 11 in the ROM cartridge 1 in the figure is determined by the ROM selecting mechanism 20.

The compressed data ROM address generation mechanism 4 is a mechanism for generating an address on the ROM when the compressed data is read in the data processing mechanism used in the present invention. When the CPU does not generate the ROM address, the data decompression mechanism 3 directly reads the compressed data of the ROM 2 through the ROM interface block 14 with the address generated by the compressed data ROM address generation mechanism 4.

However, when the CPU generates the ROM address, the address bus switching mechanism 18 and the data bus switching mechanism 19 of the transparent read mechanism 16 switch the bus to C.
Switch to the PU1 / F side to load programs and data to C
Output to PU.

The transparent read function means that the CPU expands LS.
When reading data from the ROM connected to I, a method of setting an address in the register of the decompression LSI and reading the data via the register (decompression data reading method)
Instead, the CPU reads data by a method of reading data from a normal memory.

As can be seen from FIG. 1, the program of uncompressed data can directly transfer the data from the ROM to the CPU. The transparent read function is a process of bypassing the decompression mechanism and reading the data as it is. From the perspective of the CPU, there is an expansion LSI between the CPU and ROM,
Even though the OM is not directly connected to the CPU bus, it is in the same state as the ROM connected to the CPU bus. Therefore, the compressed data can be read by the CPU in the same format.

However, in order to create such a state,
The ROM must be mapped in the CPU memory space. An address decoder (address conversion mechanism 17) does this, and the CPU address and the ROM address are associated with each other by this decoder.

When the transparent reading function described above is used, compressed data and a program can be stored in the same ROM, but in reality, since the data processing LSI is interposed between the CPU and the ROM, the CPU throughput decreases and the unit The number of execution instructions per time is smaller than that when the CPU and ROM are directly connected.

Since some games, such as those using polygons, require a large amount of data to be processed at high speed, in such a case, the system is configured by using the compressed data and the program as separate ROMs to improve throughput. Need to reach the maximum speed. On the other hand, although the speed is not so high as in an adventure game, in the case of handling a larger amount of data, it is necessary to maximize the utilization efficiency of the memory by making the compressed data and the program data the same ROM.

FIG. 8 is an explanatory diagram of a ROM configuration corresponding to FIG. 6, which is made possible by the present invention and uses a ROM storing a program and compressed data. In this configuration, RO
A program and data are stored together in M. That is, it is shown that compressed data can be shared and stored in one data ROM without separately providing a program ROM. At this time, the program storing ROM 11 shown in FIG. 1 becomes unnecessary. Further, the ROM configuration selecting mechanism 20 may be configured as shown in FIG. 6, and in this case, the program storage RO in FIG.
M11 may be added. This shows that the system configuration of the ROM can be selected according to the application as described above.

[0031]

The non-compressed data can be stored in one ROM together with the program. However, storing uncompressed data as it is in the ROM with respect to the ever-increasing amount of data increases the waste of memory.
Especially, since a lot of image data has been handled recently, there is a situation in which compressed data can be stored in one ROM, but uncompressed data cannot be stored in one ROM. There is. Data compression is an essential requirement under such circumstances.

However, when the data is compressed, the decompression of the compressed data must be dealt with by software, which causes a problem in terms of processing speed. Therefore, the compressed data is sent to the CPU
A system provided with a compressed data decompression mechanism so that it can be processed separately from the above has been considered, but a new problem has arisen in that the data ROM and the program ROM must be separated. In this way, the vicious cycle of repeating one problem to another is repeated.

This vicious circle is broken by the data processing mechanism incorporating the transparent reading mechanism and the ROM configuration selecting mechanism of the present invention. By using the data processing mechanism of the present invention, the compressed data and the program can be stored in the same ROM as well as the conventional decompression of the compressed data. As a result, the number of ROMs in the external storage device can be reduced, and the hardware cost can be reduced. Further, since the program and data can be stored in one ROM, it is not necessary to separately limit the maximum capacity of the program and the data as in the conventional case, and the maximum quantity can be limited by the total of both, so that it is possible to reduce The restrictions can be reduced.

Even when it is necessary to process the data at a higher speed, it is easy to separate the compressed data and the program into different R
Since the system can be configured as an OM, there is an effect that an optimal system can be provided depending on the characteristics of software.

[Brief description of drawings]

FIG. 1 is a block diagram of an external storage device for a computer having a transparent reading control function and a data processing function with a ROM configuration selection function of the present invention.

FIG. 2 is an explanatory diagram of an external storage device with a battery backup.

FIG. 3 is a block diagram of a home-use game machine.

FIG. 4 is an explanatory diagram of a configuration of a conventional external storage device and a home-use game machine.

FIG. 5 is a system configuration diagram using an external storage device for a computer in which a dedicated compressed data decompression mechanism is incorporated.

FIG. 6 is an explanatory diagram of a ROM configuration when a data processing mechanism having only a dedicated compressed data decompression mechanism is used.

FIG. 7 is an explanatory diagram of a ROM configuration when a data processing mechanism having a transparent read control function and a ROM configuration selection function of the present invention is used.

[Explanation of symbols]

 1 External Storage Device 2 ROM 3 Compressed Data Mechanism 4 Compressed Data ROM Address Generation Mechanism 5 ROM Bank Switching Mechanism 6 Home Game Machine Main Body 7 CPU 8 RAM 9 Image Control Means 10 Voice Control Means 11 Program Storage ROM 12 Compressed Data Storage ROM 13 data processing mechanism 14 ROM interface block 15 CPU interface block 16 transparent read control block 17 address conversion mechanism 18 address switching mechanism 19 data bus switching mechanism 20 ROM configuration selection mechanism

Claims (1)

[Claims] 1. An external storage device for a computer having a non-volatile semiconductor memory for storing data and programs and a data processing mechanism for decompressing compressed data on the memory, wherein the data processing mechanism includes a ROM selecting mechanism and a transparent reading mechanism. An external storage device for a computer characterized by the above.