LPC47M192 datasheet(57/228 Pages) SMSC

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SMSC DS – LPC47M192

Page 57

Rev. 03/30/05

DATASHEET

Verify

The Verify command is used to verify the data stored on a disk. This command acts exactly like a Read Data

command except that no data is transferred to the host. Data is read from the disk and CRC is computed and

checked against the previously-stored value.

Because data is not transferred to the host, the TC cycle cannot be used to terminate this command. By setting the

EC bit to “1”, an implicit TC will be issued to the FDC. This implicit TC will occur when the SC value has

decremented to 0 (an SC value of 0 will verify 256 sectors). This command can also be terminated by setting the EC

bit to “0” and the EOT value equal to the final sector to be checked. If EC is set to “0”, DTL/SC should be

programmed to 0FFH. Refer to Table 22 and Table 23 for information concerning the values of MT and EC versus

SC and EOT value.

Definitions:

# Sectors Per Side = Number of formatted sectors per each side of the disk.

# Sectors Remaining = Number of formatted sectors left which can be read,

including side 1 of the disk if MT is set to “1”.

Table 23 – Verify Command Result Phase Table

SC/EOT VALUE

TERMINATION RESULT

SC = DTL

EOT <= # Sectors Per Side

Success Termination

Result Phase Valid

SC = DTL

EOT > # Sectors Per Side

Unsuccessful Termination

Result Phase Invalid

SC <= # Sectors Remaining AND

EOT <= # Sectors Per Side

Successful Termination

Result Phase Valid

SC > # Sectors Remaining OR

EOT > # Sectors Per Side

Unsuccessful Termination

Result Phase Invalid

SC = DTL

EOT <= # Sectors Per Side

Successful Termination

Result Phase Valid

SC = DTL

EOT > # Sectors Per Side

Unsuccessful Termination

Result Phase Invalid

SC <= # Sectors Remaining AND

EOT <= # Sectors Per Side

Successful Termination

Result Phase Valid

SC > # Sectors Remaining OR

EOT > # Sectors Per Side

Unsuccessful Termination

Result Phase Invalid

Note:

If MT is set to “1” and the SC value is greater than the number of remaining formatted sectors on Side 0,

verifying will continue on Side 1 of the disk.

Format A Track

The Format command allows an entire track to be formatted. After a pulse from the nINDEX pin is detected, the FDC

starts writing data on the disk including gaps, address marks, ID fields, and data fields per the IBM System 34 or

3740 format (MFM or FM respectively). The particular values that will be written to the gap and data field are

controlled by the values programmed into N, SC, GPL, and D which are specified by the host during the command

phase. The data field of the sector is filled with the data byte specified by D. The ID field for each sector is supplied

by the host; that is, four data bytes per sector are needed by the FDC for C, H, R, and N (cylinder, head, sector

number and sector size respectively).

After formatting each sector, the host must send new values for C, H, R and N to the FDC for the next sector on the

track. The R value (sector number) is the only value that must be changed by the host after each sector is formatted.

This allows the disk to be formatted with nonsequential sector addresses (interleaving). This incrementing and

formatting continues for the whole track until the FDC encounters a pulse on the nINDEX pin again and it terminates

the command.

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