FDC37B78X SMSC Corporation, FDC37B78X Datasheet - Page 56

• Manufacturer Part Number: FDC37B78X
• Description: Enhanced Super I/O Controller with ACPI Support/ Real Time Clock and Consumer IR
• Manufacturer: SMSC Corporation

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.
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
If the seek portion fails, it is
00
01
02
03
07
N
TABLE 23 - SECTOR SIZES
..
56
SECTOR SIZE
1024 bytes
16 Kbytes
128 bytes
256 bytes
512 bytes
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
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.
determines the number of bytes per sector (see
Table 23 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.
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.
...
sector,
the
sector
For reads, it
address
is
N