From NeoGeo Development Wiki
See YM2610 timers.
See SSG for details on this part's operation.
See FM for details on this part's operation.
See ADPCM for details on this part's operation.
The only writable registers that can also be read are the SSG ones.
|When a timer expires and IRQ is enabled for the timer, the respective flag is set.|
|Attempting to read non-SSG registers will fail.|
|When a channel has reached the end address and stops, the respective bit is set (unless masked).|
|$07||Not implemented||Always returns $00|