SYMBOL
LOCK
NAME
DESCRIPTION
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 the DSR or DOR)
MFM
MT
MFM/FM Mode
Selector
Multi-Track
Selector
A one selects the double density (MFM) mode. A zero selects single
density (FM) mode.
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.
N
0
1
2
3
Sector Size
128 Bytes
256 Bytes
512 Bytes
1024 Bytes
…
…
NCN
ND
New Cylinder
Number
Non-DMA Mode
Flag
The desired cylinder number.
When set to 1, indicates that the FDC is to operate in the non-DMA
mode. In this mode, the host is interrupted for each data transfer.
When set to 0, the FDC operates in DMA mode, interfacing to a DMA
controller by means of the DRQ and nDACK signals.
The bits D0-D3 of the Perpendicular Mode Command can only be
modified if OW is set to 1. OW id defined in the Lock command.
The current position of the head at the completion of Sense Interrupt
Status command.
OW
Overwrite
PCN
Present Cylinder
Number
POLL
PRETRK
Polling Disable
When set, the internal polling routine is disabled. When clear, polling
is enabled.
Precompensation Programmable from track 00 to FFH.
Start Track
Number
R
Sector Address
The sector number to be read or written. In multi-sector transfers, this
parameter specifies the sector number of the first sector to be read or
written.
RCN
Relative Cylinder
Number
Relative cylinder offset from present cylinder as used by the Relative
Seek command.
39
SMSC [ SMSC CORPORATION ]
