FDC37C672QFP SMSC Corporation, FDC37C672QFP Datasheet - Page 55

• Manufacturer Part Number: FDC37C672QFP
• Description: ENHANCED SUPER I/O CONTROLLER WITH FAST IR
• Manufacturer: SMSC Corporation

Enhanced Super I/O Controller with Fast IR
Datasheet
8.2
8.2.1
8.2.2
SMSC FDC37C672
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
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:
Drives
Drives
5.25"
3.5"
All values except sector size are in hex.
FORMAT
PRELIMINARY DATASHEET
MFM
MFM
FM
FM
Table 8.8 - Typical Values for Formatting
SECTOR SIZE
512**
1024
2048
4096
1024
2048
4096
1024
512*
128
128
512
256
256
128
256
512
256
...
...
Page 55
00
00
02
03
04
05
01
01
02
03
04
05
N
...
...
0
1
2
1
2
3
SC
0F
0F
12
10
08
04
02
01
12
10
09
04
02
01
09
05
09
05
GPL1
C8
C8
0A
2A
C8
C8
1B
0E
1B
07
10
18
46
20
80
07
0F
35
GPL2
FF
FF
0C
FF
FF
09
19
30
87
32
50
F0
1B
2A
3A
36
54
74
Rev. 10-29-03