DP8473 datasheet(11/28 Pages) NSC

11 / 28 page

Result Phase Status Registers (Continued)

D5 Seek End

Seek or Recalibrate Command completed

by the Controller (Used during Sense Interrupt com-

mand)

D4 Equipment Check

After a Recalibrate Command

Track 0 signal failed to occur (Used during Sense Inter-

rupt command)

D3 Not Used

D2 Head Address

(at end of Execution Phase)

D1 D0 Drive Select

(at end of Execution Phase)

00 e Drive 0 selected 01 e Drive 1 selected

10 e Drive 2 selected 11 e Drive 3 selected

STATUS REGISTER 1 (ST1)

D7 End of Track

Controller transferred the last byte of the

last sector without the TC pin becoming active The last

sector is the End Of Track sector number programmed

in the Command Phase

D6 Not Used

D5 CRC Error

If this bit is set and bit 5 of ST2 is clear

then there was a CRC error in the Address Field of the

correct sector If bit 5 of ST2 is set then there was a

CRC error in the Data Field

D4 Over Run

Controller was not serviced by the mP soon

enough during a data transfer in the Execution Phase

TABLE VII Maximum Time Allowed to

Service an Interrupt or Acknowledge

a DMA Request in Execution Phase

Data

Time to

Rate

Service

125

620 ms

250

300 ms

500

140 ms

1000

60 ms

Time from rising edge of DRQ or INT to trailing edge of DAK or RD or WR

D3 Not Used

D2 No Data

Three possible problems 1) Controller cannot

find the sector specified in the Command Phase during

the execution of a Read Write or Scan command An

address mark was found however so it is not a blank

disk 2) Controller cannot read any Address Fields with-

out a CRC error during Read ID command 3) Controller

cannot find starting sector during execution of Read A

Track command

D1 Not Writable

Write Protect pin is active when a Write

or Format command is issued

D0 Missing Address Mark

If bit 0 of ST2 is clear then the

disk controller cannot detect any Address Field Address

Mark after two disk revolutions If bit 0 of ST2 is set then

the disk controller cannot detect the Data Field Address

Mark

STATUS REGISTER 2 (ST2)

D7 Not Used

D6 Control Mark

Controller tried to read a sector which

contained a deleted data address mark during execu-

tion of Read Data or Scan commands Or if a Read

Deleted Data command was executed a regular ad-

dress mark was detected

D5 CRC Error in Data Field

Controller detected a CRC

error in the Data Field Bit 5 of ST1 is also set

D4 Wrong Track

Only set if desired sector not found and

the track number recorded on any sector of the current

track is different from that stored in the Track Register

D3 Scan Equal Hit

‘‘Equal’’ condition satisfied during any

Scan Command

D2 Scan Not Satisfied

Controller cannot find a sector on

the track which meets the desired condition during Scan

Command

D1 Bad Track

Only set if the desired sector is not found

and the track number recorded on any sector on the

track is different from that stored in the Track Register

and the recorded track number is FF

D0 Missing Address Mark in Data Field

Controller can-

not find the Data Field Address Mark during ReadScan

command Bit 0 of ST1 is also set

STATUS REGISTER 3 (ST3)

D7 Not Used

D6 Write Protect Status

D5 Not Used

D4 Track 0 Status

D3 Not Used

D2 Head Select Status

D1 D0 Drive Selected

00 e Drive 0 selected 01 e Drive 1 selected

10 e Drive 2 selected 11 e Drive 3 selected

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