44 lines
		
	
	
		
			1.6 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
		
		
			
		
	
	
			44 lines
		
	
	
		
			1.6 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
| 
								 | 
							
								# Virtual Boy
							 | 
						||
| 
								 | 
							
								
							 | 
						||
| 
								 | 
							
								a "portable" video game console made by Nintendo in the '90's.
							 | 
						||
| 
								 | 
							
								
							 | 
						||
| 
								 | 
							
								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.
							 | 
						||
| 
								 | 
							
								
							 | 
						||
| 
								 | 
							
								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.
							 | 
						||
| 
								 | 
							
								
							 | 
						||
| 
								 | 
							
								additionally, channel 5 offers a modulation/sweep unit. the former is similar to FDS' but has much reduced speed control.
							 | 
						||
| 
								 | 
							
								
							 | 
						||
| 
								 | 
							
								# effects
							 | 
						||
| 
								 | 
							
								
							 | 
						||
| 
								 | 
							
								- `10xx`: set waveform.
							 | 
						||
| 
								 | 
							
								- `11xx`: set noise length (0 to 7).
							 | 
						||
| 
								 | 
							
								  - only in the noise channel.
							 | 
						||
| 
								 | 
							
								- `12xy`: setup envelope.
							 | 
						||
| 
								 | 
							
								  - `x` determines whether envelope is enabled or not.
							 | 
						||
| 
								 | 
							
								    - 0: disabled
							 | 
						||
| 
								 | 
							
								    - 1: enabled
							 | 
						||
| 
								 | 
							
								    - 3: enabled and loop
							 | 
						||
| 
								 | 
							
								    - yeah, the value 2 isn't useful.
							 | 
						||
| 
								 | 
							
								  - `y` sets the speed and direction.
							 | 
						||
| 
								 | 
							
								    - 0-7: down
							 | 
						||
| 
								 | 
							
								    - 8-F: up
							 | 
						||
| 
								 | 
							
								- `13xy`: setup sweep.
							 | 
						||
| 
								 | 
							
								  - `x` sets the speed.
							 | 
						||
| 
								 | 
							
								    - 0 and 8 are "speed 0" - sweep is ineffective.
							 | 
						||
| 
								 | 
							
								  - `y` sets the shift (0 to 7).
							 | 
						||
| 
								 | 
							
								    - 8 and higher will mute the channel.
							 | 
						||
| 
								 | 
							
								  - only in channel 5.
							 | 
						||
| 
								 | 
							
								- `14xy`: setup modulation.
							 | 
						||
| 
								 | 
							
								  - `x` determines whether it's enabled or not.
							 | 
						||
| 
								 | 
							
								    - 0: disabled
							 | 
						||
| 
								 | 
							
								    - 1: enabled
							 | 
						||
| 
								 | 
							
								    - 3: enabled and loop
							 | 
						||
| 
								 | 
							
								    - 2 isn't useful here either.
							 | 
						||
| 
								 | 
							
								  - `y` sets the speed.
							 | 
						||
| 
								 | 
							
								    - 0 and 8 are "speed 0" - modulation is ineffective.
							 | 
						||
| 
								 | 
							
								    - no, you can't really do Yamaha FM using this.
							 | 
						||
| 
								 | 
							
								  - only in channel 5.
							 | 
						||
| 
								 | 
							
								- `15xx`: set modulation wave.
							 | 
						||
| 
								 | 
							
								  - `xx` points to a wavetable. it should have a height of 255.
							 | 
						||
| 
								 | 
							
								  - this is an alternative to setting the modulation wave through the instrument.
							 |