LPC47N227TQFP Standard Microsystems (SMSC), LPC47N227TQFP Datasheet - Page 53

• Manufacturer Part Number: LPC47N227TQFP
• Manufacturer: Standard Microsystems (SMSC)

Specifications of LPC47N227TQFP

• Lead Free Status / RoHS Status: Not Compliant

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".
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 18 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.
The amount of data which can be handled with a single command to the FDC depends upon MT (multi-
track) and N (number of bytes/sector).
The Multi-Track function (MT) allows the FDC to read data from both sides of the diskette. For a particular
cylinder, data will be transferred starting at Sector 1, Side 0 and completing the last sector of the same
track at Side 1.
If the host terminates a read or write operation in the FDC, the ID information in the result phase is
dependent upon the state of the MT bit and EOT byte. Refer to Table 19.
Table 18 – Sector Sizes
00
01
02
03
07
N
..
Upon receipt of the TC cycle, or an implied TC (FIFO
53
SECTOR SIZE
1024 bytes
16 Kbytes
128 bytes
256 bytes
512 bytes
...