HP C2233 Product Description Manual page 53

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Block Diagram
SCSI Interface
DRAFT
10/24/90 11:07
AtmospheriC Controls
The atmospheric controls in the HDA consist of a breather
filter and a recirculating filter. The breather filter equalizes
air pressure within the HDA to ambient air p'ressure
and prevents contaminants from entering the HDA. The
recirculating filter maintains the internal cleanliness of the
HDA.
Vibration Isolators
The HDA is mounted on vibration isolators to protect it
from high frequency external vibrations.
Spindle Assembly
The spindle assembly provides the mechanical mounting
for the disks. The spindle rotates on a bearing system and
is driven by an "in hub" brushless dc motor. The drive
current for the motor is supplied by the spindle driver
circuit on the drive electronics/controller PCA. Three
Hall-effect sensors, mounted on the spindle assembly,
provide feedback signals to the spindle control electronics
for speed and phase switching control.
Refer to figure 3-4. The drive/electronics PCA controls
the operation of the drive, including head positioning, data
transfer, spindle speed, and power distribution.
The SCSI Interface is the direct electrical interface between
the SCSI channel and the drive electronics. It handles all
SCSI timing and protocol, and transfer of commands, status
and configuration information.
The SCSI interface handles SCSI protocol without
intervention from the microprocessor, and is capable
of automatically controlling the proper sequence of bus
Product Features 3-13