PC87309VLJ datasheet(75/192 Pages) NSC

75 / 192 page

The Floppy Disk Controller (FDC) (Logical Device 0)

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First Command Phase Byte

See Section 3.7.10 on page 64 for a description of these

bits.

Second Command Phase Byte

Bits 2-0 - Drive Select (DS1,0) and Head (HD) Select

See the description of the Drive Select bits (DS1,0) and

the Head (HD) in Section 3.7.10 on page 64.

Bit 7 - Enable Count Control (EC)

This bit controls whether the End of Track sector num-

ber or the Sectors to read Count (SC) triggers termina-

tion of the VERIFY command.

See also TABLE 3-26 on page 75.

0: Terminate VERIFY when the number of last sector

read equals the End of Track (EOT) sector number.

The ninth command phase byte (Sectors to read

Count, SC), is not needed and should be set to FFh.

1: Terminate VERIFY when number of sectors read

equals the number of sectors to read, i.e., Sectors

to read Count (SC).

Third through Eighth Command Phase Bytes

See Section 3.7.10 on page 64.

Always set the End of Track (EOT) sector number to the

number of the last sector to be checked on each side of

the disk. If EOT is greater than the number of sectors

per side, the command terminates with an error and no

useful Address Mark (AM) or CRC data is returned.

Ninth Command Phase Byte, Sectors to Read Count (SC)

This byte specifies the number of sectors to read. If the

Enable Count (EC) control bit (bit 7) of the second com-

mand byte is 0, this byte is not needed and should be

set to the value FFh.

Execution Phase

Data is read from the disk, as the controller checks for valid

address marks in the address and data fields.

This command is identical to the READ DATA command,

except that it does not transfer data during the execution

phase. See Section 3.7.10 on page 64.

If the Multi-Track (MT) parameter is 1 and SC is greater

than the number of remaining formatted sectors on side 0,

verification continues on side 1 of the disk.

Result Phase

TABLE 3-26 on page 75 shows how different conditions af-

fect the termination status.

TABLE 3-26. VERIFY Command Termination

Conditions

1. Number of formatted sectors per side of the disk.

2. Number of formatted sectors left which can be read,

including side 1 of the disk, if MT is 1.

End of Track (EOT) Sector Number

Bytes Between Sectors - Gap 3

Sectors to read Count (SC)

76543210

Result Phase Status Register 0 (ST0)

Result Phase Status Register 1 (ST1)

Result Phase Status Register 2 (ST2)

Track Number

Head Number

Sector Number

Bytes-Per-Sector Code

MT EC

Sector Count (SC) or

End of Track (EOT) Value

Termination

Status

SC should be FFh

EOT

≤ Sectors per Side1

No Errors

SC should be FFh

EOT > Sectors per Side

Abnormal

Termination

≤ Sectors per Side

and

≤ EOT

No Errors

SC > Sectors Remaining2

SC > EOT

Abnormal

Termination

SC should be FFh

EOT

≤ Sectors per Side

No Errors

SC should be FFh

EOT > Sectors per Side

Abnormal

Termination

≤ Sectors per Side

and

≤ EOT

No Errors

≤ (EOT x 2)

and

EOT

≤ Sectors per Side

No Errors

SC > (EOT x 2)

Abnormal

Termination

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