Apple Elite Series Computer Drive User Manual


 
ELITE SERIES USER MANUAL SPECIFICATIONS
completely disables the write logic and enables
the read data logic and stepper logic.
6.4.2. Data Signals
Read Data
This interface line returns to the controller
card the magnetic polarity of the section of the
diskette (side) which is currently passing under
the (selected) read/write head. When a section
of media with a particular magnetic polarity is
passing under the (selected) read/write head,
this interface line will be a logical low. When
a section of the media with an opposite polarity
is passing under the (selected) read/write head,
this line will be a logical high. The control-
ler cards are not as interested in the actual
logical level of this line as they are in a
change from one level to the other. Such a
transition signifies that a “1” bit was recorded
at that media location, lack of a transition
indicates a “0” bit.
Write Data
This interface line directly controls the cur-
rent flowing through the (selected) read/write
head. A logical high level on this line will
cause the (selected) read/write head to magnet—
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