Table 45 - Interrupt Identification
SE
0
1
IC
11
00
INTERRUPT DUE TO
Polling
Normal termination of Seek
or Recalibrate command
Abnormal termination of Seek
or Recalibrate command
1
01
The Seek, Relative Seek, and Recalibrate commands have no result phase. The Sense Interrupt Status command
must be issued immediately after these commands to terminate them and to provide verification of the head position
(PCN). The H (Head Address) bit in ST0 will always return a “0”. If a Sense Interrupt Status is not issued, the drive
will continue to be BUSY and may affect the operation of the next command.
Sense Drive Status
Sense Drive Status obtains drive status information. It has not execution phase and goes directly to the result phase
from the command phase. Status Register 3 contains the drive status information.
Specify
The Specify command sets the initial values for each of the three internal times. The HUT (Head Unload Time)
defines the time from the end of the execution phase of one of the read/write commands to the head unload state.
The SRT (Step Rate Time) defines the time interval between adjacent step pulses. Note that the spacing between
the first and second step pulses may be shorter than the remaining step pulses. The HLT (Head Load Time) defines
the time between when the Head Load signal goes high and the read/write operation starts. The values change
with the data rate speed selection and are documented in Table 46. The values are the same for MFM and FM.
SMSC DS – FDC37N769
Page 53 of 137
Rev. 02-16-07
DATASHEET
SMSC [ SMSC CORPORATION ]
