PC87338 datasheet(90/221 Pages) NSC

90 / 221 page

www.national.com

Bit 5 of the result phase Status register 2

(ST2) indicates when and where the error oc-

curred. See Section 3.5.3.

Bit 6 - Not Used

This bit is not used and is always 0.

Bit 7 - End of Track

This bit is set to 1 when the FDC transfers the last

byte of the last sector without the TC signal be-

coming active. The last sector is the End of Track

sector number programmed in the command

phase.

0 - The FDC did not transfer the last byte of the

last sector without the TC signal becoming ac-

tive.

1 - The FDC transferred the last byte of the last

sector without the TC signal becoming active.

3.5.3

Result Phase Status Register 2

(ST2)

FIGURE 56. ST2 Result Phase Register Bitmap

Bit 0 - Missing Address Mark Location

If the FDC cannot find the address mark of a data

field or of an address field during a read, scan, or

verify command, i.e., bit 0 of ST1 is 1, this bit indi-

cates when and where the failure occurred.

0 - The FDC failed to detect an address mark for

the address field after two disk revolutions.

1 - The FDC failed to detect an address mark for

the data field after it found the correct address

field.

Bit 1 - Bad Track

This bit indicates whether or not the FDC detected

a bad track

0 - No bad track detected.

1 - Bad track detected.

The desired sector is not found. If the track

number recorded on any sector on the track is

FFh and this number is different from the track

address specified in the command phase,

then there is a hard error in IBM format.

Bit 2 - Scan Not Satisfied

This bit indicates whether or not the value of the

data byte from the microprocessor meets any of

the conditions specified by the scan command

used.

“The SCAN EQUAL, the SCAN LOW OR EQUAL

and the SCAN HIGH OR EQUAL Commands” on

page 112 and Table 55 describes the conditions.

0 - The data byte from the microprocessor meets

at least one of the conditions specified.

1 - The data byte from the microprocessor does

not meet any of the conditions specified.

Bit 3 - Scan Satisfied

This bit indicates whether or not the value of the

data byte from the microprocessor was equal to a

byte on the floppy disk during any scan command.

0 - No equal byte was found.

1 - A byte whose value whose values is equal to

the byte from the microprocessor was found

on the floppy disk.

Bit 4 - Wrong Track

This bit indicates whether or not there was a prob-

lem finding the sector because of the track num-

ber.

0 - Sector found.

1 - Desired sector not found.

The desired sector is not found. The track

number recorded on any sector on the track is

different from the track address specified in

the command phase.

Bit 5 - CRC Error in Data Field

When the FDC detected a CRC error in the correct

sector (bit 5 of the result phase Status register 1

(ST1) is 1), this bit indicates whether it occurred in

the address field or in the data field.

0 - The CRC error occurred in the address field.

1 - The CRC error occurred in the data field.

Bit 6 - Control Mark

When the controller tried to read a sector, this bit

indicates whether or not it detected a deleted data

address mark during execution of a READ DATA

or scan commands, or a regular address mark dur-

ing execution of a READ DELETED DATA com-

mand.

0 - No control mark detected.

321

Reset

Required

Result Phase Status

Scan Not Satisfied

CRC Error in Data Field

Not Used

Scan Equal Hit

Wrong Track

Missing Address

Control Mark

Bad Track

Mark Location

PC87338 Datenblatt(PDF) 90 Page - National Semiconductor (TI)

PC87338 Datenblatt(HTML) 90 Page - National Semiconductor (TI)

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datenblatt Download

Link URL