FDC37C669_07 SMSC [SMSC Corporation], FDC37C669_07 Datasheet - Page 65

• Manufacturer Part Number: FDC37C669_07
• Description: PC 98/99 Compliant Super I/O Floppy Disk Controller with Infrared Support
• Manufacturer: SMSC [SMSC Corporation]

Note that if implied seek is not enabled, the read
and write commands should be preceded by:
1) Seek command - Step to the proper track
2) Sense
3) Read ID - Verify head is on proper track
4) Issue Read/Write command.
The Seek command does not have a result
phase. Therefore, it is highly recommended that
the Sense Interrupt Status command be issued
after the Seek command to terminate it and to
provide verification of the head position (PCN).
The H bit (Head Address) in ST0 will always
return to a "0". When exiting POWERDOWN
mode, the FDC clears the PCN value and the
status information to zero. Prior to issuing the
POWERDOWN
recommended that the user service all pending
interrupts through the Sense Interrupt Status
command.
Sense Interrupt Status
An interrupt signal on FINT pin is generated by
the FDC for one of the following reasons:
1. Upon entering the Result Phase of:
2. End of Seek, Relative Seek, or Recalibrate
3. FDC requires a data transfer during the
The Sense Interrupt Status command resets the
interrupt signal and, via the IC code and SE bit
of Status Register 0, identifies the cause of the
interrupt.
Terminate the Seek command
a. Read Data command
b. Read A Track command
c. Read ID command
d. Read Deleted Data command
e. Write Data command
f.
g. Write Deleted Data command
h. Verify command
command
execution phase in the non-DMA mode
Format A Track command
Interrupt
command,
Status
it
command
is
highly
-
65
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
information.
goes directly to the result phase from the
command phase.
the drive status information.
Specify
The Specify command sets the initial values for
each of the three internal times.
(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
SE
0
1
1
Table 27 - Interrupt Identification
and
Drive
11
00
01
IC
the
It has not execution phase and
Status
read/write
Polling
Normal termination of Seek
or Recalibrate command
Abnormal termination of
Seek or Recalibrate
command
Status Register 3 contains
INTERRUPT DUE TO
obtains
operation
drive
The HUT
starts.
status