FDC37C672 View Datasheet(PDF) - SMSC -> Microchip

Part Name

Description

Manufacturer

FDC37C672

Enhanced Super I/O Controller with Fast IR

SMSC -> Microchip 

Chapter 7

Enhanced Super I/O Controller with Fast IR

Datasheet

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 7.1 for explanations of

the various symbols used. Chapter 8 lists the required parameters and the results associated with each

command that the FDC is capable of performing.

SYMBOL

C

D

D0, D1, D2,

D3

DIR

DS0, DS1

DTL

EC

EFIFO

EIS

EOT

GAP

GPL

H/HDS

HLT

HUT

LOCK

Table 7.1 - Description of Command Symbols

NAME

Cylinder Address

Data Pattern

Drive Select 0-3

Direction Control

Disk Drive Select

Special Sector Size

Enable Count

Enable FIFO

Enable Implied Seek

End of Track

Gap Length

Head Address

Head Load Time

Head Unload Time

DESCRIPTION

The currently selected address; 0 to 255.

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

Designates which drives are perpendicular drives on the Perpendicular

Mode Command. A "1" indicates a perpendicular drive.

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.

DS1

DS0

DRIVE

0

0

drive 0

0

1

drive 1

1

0

drive 2

1

1

drive 3

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.

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

SC (number of sectors per track).

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

(default).

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.

The final sector number of the current track.

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)

SMSC FDC37C672

Page 40

DATASHEET

Rev. 10-29-03

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