US 11,942,113 B2
Method of operating hard disk drives, corresponding hard disk drive and processing device
Marco Ferrari, Voghera (IT); Davide Betta, Barzano (IT); Diego Tognoli, Tokyo (JP); and Roberto Trabattoni, Corbetta (IT)
Assigned to STMicroelectronics S.r.l., Agrate Brianza (IT); and STMicroelectronics KK, Tokyo (JP)
Filed by STMICROELECTRONICS KK, Tokyo (JP); and STMICROELECTRONICS S.r.l., Agrate Brianza (IT)
Filed on Feb. 8, 2023, as Appl. No. 18/166,291.
Claims priority of application No. 102022000003119 (IT), filed on Feb. 21, 2022.
Prior Publication US 2023/0267963 A1, Aug. 24, 2023
Int. Cl. G11B 5/54 (2006.01); G11B 5/48 (2006.01); G11B 21/08 (2006.01)
CPC G11B 21/083 (2013.01) 22 Claims
OG exemplary drawing
 
1. A method of operating a hard disk drive system comprising a plurality of voice coil motors coupled to respective control units configured to drive a retract operation of the plurality VCMs, wherein the retract operation of the plurality of VCMs comprises a sequence of retract steps, the respective control units are coupled together via a common clock line and a communication line, and respective time slots are allotted to each one of the respective control units for communication over the communication line, and the time slots are synchronized via the common clock line coupled to the respective control units, the method comprising:
in response to a first one of the respective control units driving a first sequence of retract steps in a first one of the plurality of VCMs:
communicating, by the first one of the respective control units, over the communication line at its respective time slots signals indicative of the first sequence of retract steps being performed at the first one of the plurality of VCMs,
sensing, by a second one of the respective control units, over the communication line the signals indicative of the first sequence of retract steps being performed at the first one of the plurality of VCMs, and
driving a second sequence of retract steps in a second one of the plurality of VCMs, wherein the second sequence of retract steps is performed at the second one of the plurality of VCMs in a timed relationship to the first sequence of retract steps performed at the first one of the plurality of VCMs.