FDC37B78X View Datasheet(PDF) - SMSC -> Microchip

Part Name

Description

Manufacturer

FDC37B78X

Enhanced Super I/O Controller with ACPI Support, Real Time Clock and Consumer IR

SMSC -> Microchip 

TABLE 31 - DRIVE CONTROL DELAYS (MS)

HUT

SRT

2M 1M 500K 300K 250K 2M 1M 500K 300K 250K

0 64 128 256 426 512 4

8

16 26.7 32

14

8

16 26.7 32 3.75 7.5 15 25 30

.. ..

..

..

..

..

..

..

..

..

..

E 56 112 224 373 448 0.5

1

2 3.33 4

F 60 120 240 400 480 0.25 0.5

1 1.67 2

2M

00

64

01

0.5

02

1

..

..

7F

63

7F

63.5

HLT

1M

500K

300K

250K

128

256

426

512

1

2

3.3

4

2

4

6.7

8

..

..

..

.

126

252

420

504

127

254

423

508

The choice of DMA or non-DMA operations is

made by the ND bit. When this bit is "1", the

non-DMA mode is selected, and when ND is "0",

the DMA mode is selected. In DMA mode, data

transfers are signaled by the FDRQ pin. Non-

DMA mode uses the RQM bit and the FINT pin

to signal data transfers.

Configure

The Configure command is issued to select the

special features of the FDC. A Configure

command need not be issued if the default

values of the FDC meet the system

requirements.

Configure Default Values:

EIS - No Implied Seeks

EFIFO - FIFO Disabled

POLL - Polling Enabled

FIFOTHR - FIFO Threshold Set to 1 Byte

PRETRK - Pre-Compensation Set to Track 0

EIS - Enable Implied Seek. When set to "1", the

FDC will perform a Seek operation before

executing a read or write command. Defaults to

no implied seek.

EFIFO - A "1" disables the FIFO (default). This

means data transfers are asked for on a byte-

by-byte basis. Defaults to "1", FIFO disabled.

The threshold defaults to "1".

POLL - Disable polling of the drives. Defaults to

"0", polling enabled. When enabled, a single

interrupt is generated after a reset. No polling is

performed while the drive head is loaded and

the head unload delay has not expired.

FIFOTHR - The FIFO threshold in the execution

phase of read or write commands. This is

programmable from 1 to 16 bytes. Defaults to

one byte. A "00" selects one byte; "0F" selects

16 bytes.

PRETRK - Pre-Compensation Start Track

Number. Programmable from track 0 to 255.

Defaults to track 0. A "00" selects track 0; "FF"

selects track 255.

66

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