FDC37C672 View Datasheet(PDF) - SMSC -> Microchip

Part Name

Description

Manufacturer

FDC37C672

Enhanced Super I/O Controller with Fast IR

SMSC -> Microchip 

Table 8.1 - Sector Sizes

N

SECTOR SIZE

00

128 bytes

01

256 bytes

02

512 bytes

03

1024 bytes

..

...

07

16 Kbytes

Enhanced Super I/O Controller with Fast IR

Datasheet

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 8.2.

At the completion of the Read Data command, the head is not unloaded until after the Head Unload Time

Interval (specified in the Specify command) has elapsed. If the host issues another command before the

head unloads, then the head settling time may be saved between subsequent reads.

If the FDC detects a pulse on the nINDEX pin twice without finding the specified sector (meaning that the

diskette's index hole passes through index detect logic in the drive twice), the FDC sets the IC code in

Status Register 0 to "01" indicating abnormal termination, sets the ND bit in Status Register 1 to "1"

indicating a sector not found, and terminates the Read Data Command.

After reading the ID and Data Fields in each sector, the FDC checks the CRC bytes. If a CRC error occurs

in the ID or data field, the FDC sets the IC code in Status Register 0 to "01" indicating abnormal

termination, sets the DE bit flag in Status Register 1 to "1", sets the DD bit in Status Register 2 to "1" if

CRC is incorrect in the ID field, and terminates the Read Data Command. Table 8.3 describes the effect

of the SK bit on the Read Data command execution and results. Except where noted in Table 8.3, the C or

R value of the sector address is automatically incremented (see Table 8.5).

Table 8.2 - Effects of MT and N Bits

MT N

MAXIMUM TRANSFER

CAPACITY

FINAL SECTOR READ

FROM DISK

0

1 256 x 26 = 6,656

26 at side 0 or 1

1

1 256 x 52 = 13,312

26 at side 1

0

2 512 x 15 = 7,680

15 at side 0 or 1

1

2 512 x 30 = 15,360

15 at side 1

0

3 1024 x 8 = 8,192

8 at side 0 or 1

1

3 1024 x 16 = 16,384

16 at side 1

SMSC FDC37C672

Page 50

DATASHEET

Rev. 10-29-03

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