44 lines
		
	
	
		
			1.6 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
			
		
		
	
	
			44 lines
		
	
	
		
			1.6 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
# Virtual Boy
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a "portable" video game console made by Nintendo in the '90's.
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it supposedly was the beginning of virtual reality... nah, instead it failed to sell well because you use it for 15 minutes and then you get a headache.
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its sound generation chip is called Virtual Sound Unit (VSU), a wavetable chip that is a lot like PC Engine, but unlike that, the waves are twice as tall, it doesn't go too low in terms of frequency (~D-2), and the last channel (yep, it has 6 channels) is a noise one.
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additionally, channel 5 offers a modulation/sweep unit. the former is similar to FDS' but has much reduced speed control.
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# effects
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- `10xx`: set waveform.
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- `11xx`: set noise length (0 to 7).
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  - only in the noise channel.
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- `12xy`: setup envelope.
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  - `x` determines whether envelope is enabled or not.
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    - 0: disabled
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    - 1: enabled
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    - 3: enabled and loop
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    - yeah, the value 2 isn't useful.
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  - `y` sets the speed and direction.
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    - 0-7: down
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    - 8-F: up
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- `13xy`: setup sweep.
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  - `x` sets the speed.
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    - 0 and 8 are "speed 0" - sweep is ineffective.
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  - `y` sets the shift (0 to 7).
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    - 8 and higher will mute the channel.
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  - only in channel 5.
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- `14xy`: setup modulation.
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  - `x` determines whether it's enabled or not.
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    - 0: disabled
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    - 1: enabled
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    - 3: enabled and loop
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    - 2 isn't useful here either.
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  - `y` sets the speed.
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    - 0 and 8 are "speed 0" - modulation is ineffective.
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    - no, you can't really do Yamaha FM using this.
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  - only in channel 5.
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- `15xx`: set modulation wave.
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  - `xx` points to a wavetable. it should have a height of 255.
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  - this is an alternative to setting the modulation wave through the instrument.
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