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Table 19 - Description of Command Symbols
SYMBOL
NAME
DESCRIPTION
EIS
Enable Implied
Seek
When set, a seek operation will be performed before executing any
read or write command that requires the C parameter in the
command phase. A "0" disables the implied seek.
EOT
End of Track
The final sector number of the current track.
GAP
Alters Gap 2 length when using Perpendicular Mode.
GPL
Gap Length
The Gap 3 size. (Gap 3 is the space between sectors excluding
the VCO synchronization field).
H/HDS
Head Address
Selected head: 0 or 1 (disk side 0 or 1) as encoded in the sector
ID field.
HLT
Head Load Time
The time interval that FDC waits after loading the head and before
initializing a read or write operation.
Refer to the Specify
command for actual delays.
HUT
Head Unload
Time
The time interval from the end of the execution phase (of a read or
write command) until the head is unloaded. Refer to the Specify
command for actual delays.
LOCK
Lock
defines
whether
EFIFO,
FIFOTHR,
and
PRETRK
parameters of the CONFIGURE COMMAND can be reset to their
default values by a "software Reset". (A reset caused by writing to
the appropriate bits of either tha DSR or DOR)
MFM
MFM/FM Mode
Selector
A one selects the double density (MFM) mode.
A zero selects
single density (FM) mode.
MT
Multi-Track
Selector
When set, this flag selects the multi-track operating mode. In this
mode, the FDC treats a complete cylinder under head 0 and 1 as
a single track. The FDC operates as this expanded track started
at the first sector under head 0 and ended at the last sector under
head 1. With this flag set, a multitrack read or write operation will
automatically continue to the first sector under head 1 when the
FDC finishes operating on the last sector under head 0.
N
Sector Size Code
This specifies the number of bytes in a sector. If this parameter is
"00", then the sector size is 128 bytes.
The number of bytes
transferred is determined by the DTL parameter. Otherwise the
sector size is (2 raised to the "N'th" power) times 128. All values
up to "07" hex are allowable. "07"h would equal a sector size of
16k. It is the user's responsibility to not select combinations that
are not possible with the drive.