LPC47N267 datasheet(38/180 Pages) SMSC

38 / 180 page

SMSC DS – LPC47N267

Page 38

Rev. 10/23/2000

SYMBOL

NAME

DESCRIPTION

DTL

Special Sector

Size

By setting N to zero (00), DTL may be used to control the number of

bytes transferred in disk read/write commands. The sector size (N =

0) is set to 128. If the actual sector (on the diskette) is larger than

DTL, the remainder of the actual sector is read but is not passed to

the host during read commands; during write commands, the

remainder of the actual sector is written with all zero bytes. The CRC

check code is calculated with the actual sector. When N is not zero,

DTL has no meaning and should be set to FF HEX.

Enable Count

When this bit is "1" the "DTL" parameter of the Verify command

becomes SC (number of sectors per track).

EFIFO

Enable FIFO

This active low bit when a 0, enables the FIFO. A "1" disables the

FIFO (default).

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 the DSR or DOR)

MFM

MFM/FM Mode

Selector

A one selects the double density (MFM) mode. A zero selects single

density (FM) mode.

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.

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.

SECTOR SIZE

128 Bytes

256 Bytes

512 Bytes

1024 Bytes

…

16K Bytes

NCN

New Cylinder

Number

The desired cylinder number.

Non-DMA Mode

Flag

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.

LPC47N267 Datasheet(PDF) 38 Page - SMSC Corporation

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