PC87311A datasheet(27/78 Pages) NSC

27 / 78 page

40 FDC Command Set Description (Continued)

Result Phase

Status Register 0

Status Register 1

Status Register 2

Track Number

Head Number

Sector Number

Bytes per Sector

SCAN LOW OR EQUAL

Command Phase

MFM

IPS

DR1

DR0

Track Number

Drive Head Number

Sector Number

Bytes per Sector

End of Track Sector Number

Intersector Gap Length

Sector Step Size

Execution Phase

Data transferred from system to control-

ler is compared to data read from disk

Result Phase

Status Register 0

Status Register 1

Status Register 2

Track Number

Head Number

Sector Number

Bytes per Sector

SEEK

Command Phase

00001111

XXXXX

DR1

DR0

New Track Number

MSN of Track Number

0000

Note

Last Command Phase byte is required only if ETR is set in Mode

Command

Execution Phase

Disk drive head is stepped in or out to a

programmable track

No Result Phase

SENSE DRIVE STATUS

Command Phase

00000

XXXXXHDDR1

DR0

Execution Phase

Disk drive status information is detected

and reported

Result Phase

Status Register 3

SENSE INTERRUPT

Command Phase

00001000

Execution Phase

Status of interrupt is reported

Result Phase

Status Register 0

Present Track Number (PTR)

MSN of PTR

0000

Note

Third Result Phase byte can only be read if ETR is set in the Mode

Command

SET TRACK

Command Phase

0WNR100

MSB

DR1

DR0

New Track Number (PTR)

Execution Phase

Internal register is read or written

Result Phase

Value

SPECIFY

Command Phase

0000001

Step Rate Time

Motor Off Time

Motor On Time

DMA

Execution Phase

Internal registers are written

No Result Phase

VERIFY

Command Phase

MFM

DR1

DR0

Track Number

Drive Head Number

Sector Number

Bytes per Sector

End of Track Sector Number

Intersector Gap Length

Data LengthSector Count

Execution Phase

Data is read from disk but not transferred

to the system

PC87311A Datasheet(PDF) 27 Page - National Semiconductor (TI)

PC87311A Datasheet(HTML) 27 Page - National Semiconductor (TI)

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