PC87310 datasheet(30/52 Pages) NSC

30 / 52 page

40 Functional Description (Continued)

SCAN HIGH OR EQUAL

Compare on a byte-by-byte basis the

P and disk data from the specified

sector match on le

Command Phase

MT MFM SK

IPS

HD DR1 DR0

Track Number

Drive Head Number

Sector Number

Number of Bytes per Sector

End of Track Sector Number

Intersector Gap Length

Sector Step Size

Result Phase

Status Register 0

Status Register 1

Status Register 2

Track Number

Head Number

Sector Number

BytesSector

SENSE DRIVE STATUS

Read the ready status of the specified

drive

Command Phase

00000100

HD DR1 DR0

Result Phase

Status Register 3

SPECIFY

The step head load and unload times

Command Phase

00000011

Step Rate Time

Motor Off Time

Motor On Time

DMA

SEEK

The specified track by reading the ad-

dress field and stepping the head

Command Phase

00001111

XXXXXX

DR1 DR0

New Track Number

MSB of Track

Note 2

MODE

Select various controller options (eg

motor timer low power implied seek

etc)

Command Phase

00000001

TMR IAF

IPS

ETR

00000000

WLD

Head Settle

00000

Note 3

RECALIBRATE

Move the head to Track 0 (max steps

77 extd 3917)

Command Phase

00000111

000000

DR1 DR0

SET TRACK

Set the current track register to the

most recent track read

Command Phase

0R W

100001

MSB DR1 DR0

New Track Number

Result Phase

Value

Note 3

SENSE INTERRUPT

Read the interrupt status

Command Phase

00001000

Result Phase

Status Register 0

Present Track Number (PTN)

MSN PTN

Note 2

INVALID COMMAND

Has been specified

Command Phase

Invalid Op Codes

Result Phase

Status Register 0

Note 1

The IPS bit is only enabled if the IPS bit in the mode command is set Otherwise this bit is a don’t care

Note 2

Shaded byte only written or read if the extended track range mode is enabled in the Mode Command (ET) e 1

Note 3

These commands are additional enhanced commands

PC87310 Datasheet(PDF) 30 Page - National Semiconductor (TI)

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