LPC47M14X datasheet(42/205 Pages) SMSC

42 / 205 page

SMSC DS – LPC47M14X

Page 42

Rev. 03/19/2001

Table 17 – Description of Command Symbols

SYMBOL

NAME

DESCRIPTION

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 "Nth" 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

128 Bytes

256 Bytes

512 Bytes

1024 Bytes

…

07 16K Bytes

NCN

New Cylinder

Number

The desired cylinder number.

Non-DMA Mode

Flag

Write ‘0’. This part does not support non-DMA mode.

Overwrite

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.

PCN

Present Cylinder

Number

The current position of the head at the completion of Sense Interrupt

Status command.

POLL

Polling Disable

When set, the internal polling routine is disabled. When clear, polling

is enabled.

PRETRK

Precompensation

Start Track

Number

Programmable from track 00 to FFH.

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.

Number of

Sectors Per Track

The number of sectors per track to be initialized by the Format

command. The number of sectors per track to be verified during a

Verify command when EC is set.

Skip Flag

When set to 1, sectors containing a deleted data address mark will

automatically be skipped during the execution of Read Data. If Read

Deleted is executed, only sectors with a deleted address mark will be

accessed. When set to "0", the sector is read or written the same as

the read and write commands.

SRT

Step Rate Interval The time interval between step pulses issued by the FDC.

Programmable from 0.5 to 8 milliseconds in increments of 0.5 ms at

the 1 Mbit data rate. Refer to the SPECIFY command for actual

delays.

ST0

ST1

ST2

ST3

Status 0

Status 1

Status 2

Status 3

Registers within the FDC that store status information after a

command has been executed. This status information is available to

the host during the result phase after command execution.

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