Data Lines - Siemens Microfloppy FDD100-5 Operating And Maintenance Manual

2.4.2.2 Index/Sector (J1-8). For soft sector operation that uses single-hole media, this line
transmits a reference Index pulse once every diskette rotation to indicate the beginning of a track.
For hard sector operation that uses multi-hole media, this line transmits the Index pulse and all
Sector pulses, where Sector pulses indicate the beginning of a sector. Pulse width for both Index and
Sector is 4
±
1.5 milliseconds. An optional set of photosensors are installed on some configurations
of the Model FDD100-5 Disk Drive to enable either side of the diskette to be recorded. Index/Sector
timing is shown in Figure 2-9.
SOFT SECTOR (INDEX ONLY)
r f - - - - - - - - 2 0 0
M S E C - - - - - -.... ~ ..
I
U
ss
U-
--.l
14--4 MSEC
+
1.5 MSEC
HARD SECTOR (16 TAKEN AS AN ILLUSTRATION)
SECTOR INDEX SECTOR
15 0
SECTOR
1
SECTOR INDEX
15
I
I I
I
6.25 MSEC------: j4-12.5 MSEC----!
I
, . ... . . - - - - - - - 2 0 0 MSEC--------t ... 1
Figure 2-9. Index/Sector Timing
2.4.2.3 Write Protect (J 1-28). A photosensor assembly senses the presence or absence of a
notch in the diskette. If a notch is not detected, a low-level signal is transmitted to the controller
to indicate that a Read-only diskette has been inserted into the Model FDD100-5 Disk Drive. This
condition also inhibits writing data on the diskette.
2.4.3 DATA LINES
Data lines are used to write data on or to read data from the diskette.
2.4.3.1 Composite Write Data (J 1-22). The controller uses this line to transmit information
to be encoded on the diskette of the selected disk drive. Pulse widths of clock and data bits should
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