FDC37C672QFP SMSC Corporation, FDC37C672QFP Datasheet - Page 40

• Manufacturer Part Number: FDC37C672QFP
• Description: ENHANCED SUPER I/O CONTROLLER WITH FAST IR
• Manufacturer: SMSC Corporation

Chapter 7
SMSC FDC37C672
C
D
D0, D1, D2,
D3
DIR
DS0, DS1
DTL
EC
EFIFO
EIS
EOT
GAP
GPL
H/HDS
HLT
HUT
LOCK
SYMBOL
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.
Cylinder Address
Data Pattern
Drive Select 0-3
Direction Control
Disk Drive Select
Special Sector Size
Enable Count
Enable FIFO
Enable Implied Seek When set, a seek operation will be performed before executing any read or
End of Track
Gap Length
Head Address
Head Load Time
Head Unload Time
NAME
Command Set/Descriptions
Table 7.1 - Description of Command Symbols
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.
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).
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)
DATASHEET
DS1
0
0
1
1
Page 40
DESCRIPTION
DS0
0
1
0
1
Enhanced Super I/O Controller with Fast IR
DRIVE
drive 0
drive 1
drive 2
drive 3
Rev. 10-29-03
Datasheet