
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”. 
SMSC DS – LPC47M192 
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Rev. 03/30/05 
DATASHEET 
Table 23  –  Verify Command Result Phase Table 
MT
EC
SC/EOT VALUE
TERMINATION RESULT
Success Termination 
Result Phase Valid 
Unsuccessful Termination 
Result Phase Invalid 
Successful Termination 
Result Phase Valid 
Unsuccessful Termination 
Result Phase Invalid 
Successful Termination 
Result Phase Valid 
Unsuccessful Termination 
Result Phase Invalid 
Successful Termination 
Result Phase Valid 
Unsuccessful Termination 
Result Phase Invalid 
0 
0 
SC = DTL 
EOT <= # Sectors Per Side 
SC = DTL 
EOT > # Sectors Per Side 
SC <= # Sectors Remaining AND 
EOT <= # Sectors Per Side 
SC > # Sectors Remaining OR 
EOT > # Sectors Per Side 
SC = DTL 
EOT <= # Sectors Per Side 
SC = DTL 
EOT > # Sectors Per Side 
SC <= # Sectors Remaining AND 
EOT <= # Sectors Per Side 
SC > # Sectors Remaining OR 
EOT > # Sectors Per Side 
0 
0 
0 
1 
0 
1 
1 
0 
1 
0 
1 
1 
1 
1 
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.