Apple 13-0010--001 Computer Drive User Manual


 
ELITE SERIES USER MANUAL THEORY OF OPERATION
The following are typical examples of the use of
device address assignments (slot #6 is assumed
and the X-reg contains $60).
Stepper Phase Off/On
Each of the four phases (0-3) must be turned on
and off again. In ascending order, the arm is
moved inward, in descending order the ann is
moved outward. The timing between accesses to
these locations is critical and the SEEK command
in RWTS should be used to move the arm.
The following example assumes the drive is al-
ready selected, motor on, not in write mode, and
has two stepper motor phases per track (standard
for the Elite One, Elite Two, and Disk II), and
it will move the head from the source track
SRCTRK to destination track DSTTRK. The seek
speed is controlled by the routine DELAY which
should loop for approximately 15 milliseconds
(for the purposes of the example) prior to re-
turning.
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