Communication between headstack and PCB on Seagate and WD

[BlackST]

Anyone working on the protocol / communication between headstack and PCB on these model :

WD ROYL
WD HULK
WD CAVIAR old models

SEAGATE NHAWK / TLITE
SEAGATE TONKA / TONKA 2 / GALAXY
SEAGATE MOOSE

i.e. how preamp IDentify , what is the protocol, data flow, hardware mapping... NOT the raw data from head. Want to exchange opinions and experiences, in PM ONLY.

P.S. I hope I am not the only one working on these subjects...