and is not needed for normal operation. Once
the Perpendicular Mode command is invoked,
FDC software behavior from the user standpoint
is unchanged.
1. The GAP2 written to a perpendicular drive
during a write operation will depend upon the
programmed data rate.
2. The write pre-compensation given to a
perpendicular mode drive will be 0ns.
3. For D0-D3 programmed to "0" for
conventional mode drives any data written
will be at the currently programmed write
pre-compensation.
The perpendicular mode command is enhanced
to allow specific drives to be designated
Perpendicular
recording
drives. This
enhancement allows data transfers between
Conventional and Perpendicular drives without
having to issue Perpendicular mode commnds
between the accesses of the different drive
types, nor having to change write pre-
compensation values.
Note: Bits D0-D3 can only be overwritten when
OW is programmed as a "1".If either
GAP or WGATE is a "1" then D0-D3 are
ignored.
When both GAP and WGATE bits of the
PERPENDICULAR MODE COMMAND are both
programmed to "0" (Conventional mode), then
D0, D1, D2, D3, and D4 can be programmed
independently to "1" for that drive to be set
automatically to Perpendicular mode. In this
mode the following set of conditions also apply:
Software and hardware resets have the
following effect on the PERPENDICULAR
MODE COMMAND:
1. "Software" resets (via the DOR or DSR
registers) will only clear GAP and WGATE
bits to "0". D0-D3 are unaffected and retain
their previous value.
2. "Hardware"
resets will clear all bits
(GAP, WGATE and D0-D3) to "0", i.e all
conventional mode.
64
SMSC [ SMSC CORPORATION ]
