FDC37C935-QS Standard Microsystems (SMSC), FDC37C935-QS Datasheet - Page 36

• Manufacturer Part Number: FDC37C935-QS
• Manufacturer: Standard Microsystems (SMSC)

Specifications of FDC37C935-QS

• Lead Free Status / RoHS Status: Supplier Unconfirmed

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
C
D
D0, D1, D2,
D3
DIR
DS0, DS1
DTL
EC
EFIFO
EIS
EOT
SYMBOL
the
command.
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
NAME
Table 19 - Description of Command Symbols
If it is invalid, an
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).
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.
DS1
0
0
1
1
36
Interrupt Status command which returns an
invalid command error. Refer to Table 19 for
explanations of the various symbols used. Table
20 lists the required parameters and the results
associated with each command that the FDC is
capable of performing.
DS0
DESCRIPTION
0
1
0
1
DRIVE
drive 0
drive 1
drive 2
drive 3