FDC37C672QFP SMSC Corporation, FDC37C672QFP Datasheet - Page 49

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

Enhanced Super I/O Controller with Fast IR
Datasheet
Note:
8.1
8.1.1
SMSC FDC37C672
Command
Result
Command
Result
PHASE
PHASE
SC is returned if the last command that was issued was the Format command. EOT is returned if the last
command was a Read or Write.
These bits are used internally only. They are not reflected in the Drive Select pins. It is the user's
responsibility to maintain correspondence between these bits and the Drive Select pins (DOR).
Data Transfer Commands
All of the Read Data, Write Data and Verify type commands use the same parameter bytes and return the
same results information, the only difference being the coding of bits 0-4 in the first byte.
An implied seek will be executed if the feature was enabled by the Configure command. This seek is
completely transparent to the user. The Drive Busy bit for the drive will go active in the Main Status
Register during the seek portion of the command. If the seek portion fails, it is reflected in the results
status normally returned for a Read/Write Data command. Status Register 0 (ST0) would contain the error
code and C would contain the cylinder on which the seek failed.
Read Data
A set of nine (9) bytes is required to place the FDC in the Read Data Mode. After the Read Data
command has been issued, the FDC loads the head (if it is in the unloaded state), waits the specified head
settling time (defined in the Specify command), and begins reading ID Address Marks and ID fields. When
the sector address read off the diskette matches with the sector address specified in the command, the
FDC reads the sector's data field and transfers the data to the FIFO.
After completion of the read operation from the current sector, the sector address is incremented by one
and the data from the next logical sector is read and output via the FIFO. This continuous read function is
called "Multi-Sector Read Operation". Upon receipt of TC, or an implied TC (FIFO overrun/underrun), the
FDC stops sending data but will continue to read data from the current sector, check the CRC bytes, and
at the end of the sector, terminate the Read Data Command.
N determines the number of bytes per sector (see Table 8.1 below). If N is set to zero, the sector size is
set to 128. The DTL value determines the number of bytes to be transferred. If DTL is less than 128, the
FDC transfers the specified number of bytes to the host. For reads, it continues to read the entire 128-
byte sector and checks for CRC errors. For writes, it completes the 128-byte sector by filling in zeros. If N
is not set to 00 Hex, DTL should be set to FF Hex and has no impact on the number of bytes transferred.
R/W
R/W
W
W
R
R
PRELIMINARY DATASHEET
D7
LOCK
D7
0
D6
───── Invalid Codes ─────
─────── ST0 ───────
D6
D5
0
0
DATA BUS
D5
D4
0
0
INVALID CODES
DATA BUS
Page 49
D3
LOCK
D4
1
LOCK
D2
D3
0
0
D1
D2
1
0
D0
D1
Invalid Command Codes (NoOp -
FDC goes into Standby State)
ST0 = 80H
0
0
D0
0
0
Command Codes
REMARKS
REMARKS
Rev. 10-29-03