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 PSG: 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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| 
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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. | 
