EIF format

Type: FM instrument

EIF ("Echo Instrument Format") is a format for FM instruments introduced by Echo. The suggested file extension is ".eif".

An EIF instrument is 29 bytes long and it's essentially the values for every YM2612 register. The first byte is YM2612 register $B0+, then come registers $30+, $34+, $38+… up to $9C+. That's it.

Bits that are not used by the YM2612 are required to be 0. Sound drivers may rely on this.