Amusement devices: games – Aerial projectile game; game element or accessory therefor... – Target
Patent
1991-09-02
1994-05-31
Robertson, David L.
Amusement devices: games
Aerial projectile game; game element or accessory therefor...
Target
273435, G06F 1300
Patent
active
053177142
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a digital sound source apparatus and an external memory cartridge used therefor. More particularly, the present invention relates to a digital sound source apparatus in which quantized data associated with sounds such as music and a sound effect are stored in a memory and an analog sound signal is generated on the basis of the quantized data in, for example, a television game set, with an external memory cartridge associated therewith.
PRIOR ART
A conventional digital sound source apparatus includes a circuit configuration as shown in FIG. 7. In FIG. 7, a semiconductor memory (hereinafter memory) 4 storing quantized data used to produce sounds is connected to a central processing unit I through an address bus 2 and a data bus 3. When an analog sound signal is generated by reading the quantized data stored in the memory 4 and subjecting the same to digital-to-analog conversion, the following processing is carried out.
In a first step, the CPU 1 applies an address to the memory 4 address data in which the first quantized data of a certain sound is stored and at the same time, causes a read signal R to assume a high level, to thus read the first quantized data and load it into an accumulator 1a. In a second step, the CPU 1 generates address data which designates a data register 6 and applies the address to an address decoder 5, outputs a write signal W and outputs the quantized data loaded into the accumulator 1a onto the data bus 3. Responsively, the address decoder 5 decodes the address data, detects write signal W and applies a write pulse MT to the data register 6. As a result, the data register 6 reads the quantized data, and temporarily stores it until a next write pulse when quantized data are applied. The quantized data stored in the data register 6 is applied to a digital/analog (hereafter D/A) conversion circuit 7 and is converted into an analog signal to be outputted to, for example, an amplifier circuit (not shown).
Such an operation is performed every time quantized data stored in each of addresses in the quantized data storage area of the memory 4 is read.
According to the prior art, the CPU 1 must sequentially perform operations such as (1) addressing of the external memory 4, (2) outputting of a read signal, (3) addressing the data register 6, and outputting of a write signal so as to read quantized data from a designated address and convert the data into an analog signal. Thus a long processing time is required to generate a sound. Therefore, the burden on the CPU 1 is large. In addition, since the number of program steps for generating a sound is high, not only is the program execution time long, but also the required storage capacity is increased.
Moreover, when the digital sound source apparatus is applied to an information processing unit for displaying or processing an image as well as generating a sound as in a television game set, for example, the CPU 1 is used for generating music, a sound effect or the like and is also used for image display. Accordingly, when the time taken to perform processing for generating a sound is long, the capabilities such as a capability to display an image is reduced. In order to prevent the capability to display an image from being reduced, a method of using a high-speed CPU or a CPU dedicated to a sound generating circuit may be considered. In this case, however, the cost of the digital sound source apparatus is high. In addition, this method is not compatible with previously sold information processing units.
SUMMARY OF THE INVENTION
A principal object of the present invention is to provide a digital sound source apparatus capable of performing processing for generating a sound with fewer steps, thus reducing the burden on the central processing unit.
Another object of the present invention is to provide an external memory cartridge used for such a digital sound source apparatus which is detachable from the central processing unit.
A digital sound source apparatus according to the present inventio
REFERENCES:
patent: 5026051 (1991-06-01), Lowe et al.
patent: 5095798 (1992-03-01), Okada et al.
Nakagawa Katsuya
Tanaka Hideki
Yamato Satoshi
Nintendo Co. Ltd.
Robertson David L.
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