
SMSC DS – LPC47M192 
Page 46 
Rev. 03/30/05 
DATASHEET 
Table 16  –  Description of Command Symbols 
SYMBOL
GAP 
GPL 
NAME
Gap Length 
DESCRIPTION
Alters Gap 2 length when using Perpendicular Mode. 
The Gap 3 size.  (Gap 3 is the space between sectors excluding the 
VCO synchronization field). 
Selected head:  0 or 1 (disk side 0 or 1) as encoded in the sector ID 
field. 
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. 
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 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) 
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.          
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 
SECTOR SIZE 
00 
128 Bytes 
01 
256 Bytes 
02 
512 Bytes 
03 
1024 Bytes 
…               … 
07 
16K Bytes 
The desired cylinder number. 
H/HDS 
Head Address 
HLT 
Head Load Time 
HUT 
Head Unload 
Time 
LOCK 
MFM 
MFM/FM Mode 
Selector 
Multi-Track 
Selector 
MT 
N 
Sector Size Code 
NCN 
New Cylinder 
Number 
Non-DMA Mode 
Flag 
Overwrite 
ND 
Write ‘0’.  This part does not support non-DMA mode. 
OW 
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. 
When set, the internal polling routine is disabled.  When clear, polling 
is enabled. 
Programmable from track 00 to FFH. 
PCN 
Present Cylinder 
Number 
Polling Disable 
POLL 
PRETRK 
Precompensation 
Start Track 
Number 
Sector Address 
R 
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.