Z80 interrupts
IRQ
Z80 IRQs can be generated by the YM2610, and are mostly used to time music playback.
The vector address is $0038.
They can be disabled in software (DI/EI).
NMI
Non Maskable Interrupts are triggered when the 68k sends a sound command.
The vector address is $0066.
They can only be disabled through ports $08 and $18.