* Port &F884 read/write to the selected page 1 register
You can also use the CRTC cursor registers to program the raster interruption located at &0066. It works both on PlayCity and on Play2CPC.
The OPN3 soundchip is mostly a light version of the OPNA soundchip with some functionalities removed: no external ADPCM, no Composite Sine Mode and no GPIO.