code: function() {
  		var cpu = this.cpu,
  		    ppu = this.ppu,
  		    apu = this.apu;
  
  		while ( !ppu.frameEnded ) {
  			cpu.tick();
  
  			ppu.tick();
  			ppu.tick();
  			ppu.tick();
  
  			if ( this.tickAPU ) {
  				apu.tick();
  			}
  			this.tickAPU = !this.tickAPU;
  		}
  
  		ppu.frameEnded = false;
  	}
docs: Run a single frame (1/60s NTCS, 1/50s PAL).