27 lines
		
	
	
		
			882 B
		
	
	
	
		
			Markdown
		
	
	
	
	
	
			
		
		
	
	
			27 lines
		
	
	
		
			882 B
		
	
	
	
		
			Markdown
		
	
	
	
	
	
# Yamaha YM2151
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the sound chip powering the Arcade system, available for standalone use if you want to make X68000 music or pair it with a 16-channel Sega PCM when it comes.
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# effects
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- `10xx`: set noise frequency of channel 8 operator 4. 00 disables noise while 01 to 20 enables it.
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- `11xx`: set feedback of channel.
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- `12xx`: set operator 1 level.
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- `13xx`: set operator 2 level.
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- `14xx`: set operator 3 level.
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- `15xx`: set operator 4 level.
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- `16xy`: set multiplier of operator.
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  - `x` is the operator (1-4).
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  - `y` is the mutliplier.
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- `17xx`: set LFO speed.
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- `18xx`: set LFO waveform. `xx` may be one of the following:
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  - `00`: saw
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  - `01`: square
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  - `02`: triangle
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  - `03`: noise
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- `19xx`: set attack of all operators.
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- `1Axx`: set attack of operator 1.
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- `1Bxx`: set attack of operator 2.
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- `1Cxx`: set attack of operator 3.
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- `1Dxx`: set attack of operator 4.
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