FDC37N869 View Datasheet(PDF) - SMSC -> Microchip
Part Name
Description
MFG CO.
FDC37N869
SMSC -> Microchip
'FDC37N869' PDF : 147 Pages View PDF
5.25”
Drives
3.5”
Drives
FORMAT
FM
Table 41 - Typical Values for Formatting
SECTOR SIZE
N
SC
128
128
512
1024
2048
4096
...
00
12
00
10
02
08
03
04
04
02
05
01
...
GPL1
07
10
18
46
C8
C8
MFM
256
256
512*
1024
2048
4096
...
01
12
0A
01
10
20
02
09
2A
03
04
80
04
02
C8
05
01
C8
...
128
FM
256
512
0
0F
07
1
09
0F
2
05
1B
MFM
256
512**
1024
1
0F
0E
2
09
1B
3
05
35
GPL2
09
19
30
87
FF
FF
0C
32
50
F0
FF
FF
1B
2A
3A
36
54
74
GPL1 = suggested GPL values in Read and Write commands to avoid splice point
between data field and ID field of contiguous sections.
GPL2 = suggested GPL value in Format A Track command.
*PC/AT values (typical)
**PS/2 values (typical). Applies with 1.0 MB and 2.0 MB drives.
Note: All values except sector size are in hex.
Control Commands
Control commands differ from the other commands in that no data transfer takes place. Three commands
generate an interrupt when complete: Read ID, Recalibrate, and Seek. The other control commands do not
generate an interrupt.
Read ID
The Read ID command is used to find the present position of the recording heads. The FDC stores the values
from the first ID field it is able to read into its registers. If the FDC does not find an ID address mark on the diskette
after the second occurrence of a pulse on the nINDEX pin, it then sets the IC code in Status Register 0 to “01”
(abnormal termination), sets the MA bit in Status Register 1 to “1”, and terminates the command.
The following commands will generate an interrupt upon completion. They do not return any result bytes. It is
highly recommended that control commands be followed by the Sense Interrupt Status command. Otherwise,
valuable interrupt status information will be lost.
Recalibrate
This command causes the read/write head within the FDC to retract to the track 0 position. The FDC clears the
contents of the PCN counter and checks the status of the nTR0 pin from the FDD. As long as the nTR0 pin is low,
the DIR pin remains 0 and step pulses are issued. When the nTR0 pin goes high, the SE bit in Status Register
0 is set to “1” and the command is terminated. If the nTR0 pin is still low after 79 step pulses have been issued,
the FDC sets the SE and the EC bits of Status Register 0 to “1” and terminates the command. Disks capable of
handling more than 80 tracks per side may require more than one Recalibrate command to return the head back
to physical Track 0. The Recalibrate command does not have a result phase. The Sense Interrupt Status
command must be issued after the Recalibrate command to effectively terminate it and to provide verification of the
SMSC DS – FDC37N869
Page 52
Rev. 11/09/2000
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