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25 lines
1.1 KiB
Markdown
25 lines
1.1 KiB
Markdown
# NES
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the console from Nintendo that plays Super Mario Bros. and helped revive the agonizing video game market in the US during mid-80s.
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also known as Famicom. it is a five-channel sound generator: first two channels play pulse wave with three different duty cycles, third is a fixed-volume triangle channel, fourth is a noise channel (can work in both pseudo-random and periodic modes) and fifth is a (D)PCM sample channel.
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# effects
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- `11xx`: write to delta modulation counter.
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- this may be used to attenuate the triangle and noise channels.
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- will not work if a sample is playing.
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- `12xx`: set duty cycle or noise mode of channel.
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- may be 0-3 for the pulse channels and 0-1 for the noise channel.
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- `13xy`: setup sweep up.
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- `x` is the time.
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- `y` is the shift.
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- set to 0 to disable it.
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- `14xy`: setup sweep down.
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- `x` is the time.
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- `y` is the shift.
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- set to 0 to disable it.
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- `18xx`: set PCM channel mode.
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- `00`: PCM (software).
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- `01`: DPCM (hardware).
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- when in DPCM mode, samples will sound muffled (due to its nature), availables pitches are limited and loop point is ignored.
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