LPC47M182 datasheet(56/223 Pages) SMSC

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Advanced I/O Controller with Motherboard GLUE Logic

Datasheet

Revision 1.8 SMSC/Non-SMSC Register Sets (02-24-05)

SMSC LPC47M182

DATASHEET

RQM and DIO must both equal “1” before the result bytes may be read. After all the result bytes have

been read, the RQM and DIO bits switch to “1” and “0” respectively, and the CB bit is cleared, indicating

that the FDC is ready to accept the next command.

6.10

Command Set/Descriptions

Commands can be written whenever the FDC is in the command phase. Each command has a unique set

of needed parameters and status results. The FDC checks to see that the first byte is a valid command

and, if valid, proceeds with the command. If it is invalid, an interrupt is issued. The user sends a Sense

Interrupt Status command which returns an invalid command error. Refer to Table 6.16 for explanations of

the various symbols used. Table 6.17 lists the required parameters and the results associated with each

command that the FDC is capable of performing.

Table 6.16 – Description of Command Symbols

SYMBOL

NAME

DESCRIPTION

Cylinder Address

The currently selected address; 0 to 255.

Data Pattern

The pattern to be written in each sector data field during formatting.

D0, D1

Drive Select 0-1

Designates which drives are perpendicular drives on the

Perpendicular Mode Command. A “1” indicates a perpendicular

drive.

DIR

Direction Control

If this bit is 0, then the head will step out from the spindle during a

relative seek. If set to a 1, the head will step in toward the spindle.

DS0, DS1

Disk Drive Select

DS1

DS0

DRIVE

Drive 0

Drive 1

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.

LPC47M182 Datasheet(PDF) 56 Page - SMSC Corporation

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