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

with a corresponding Drive Select line; therefore, they can be activated only by the corresponding
Drive Select command from the controller. In a mUltiple-drive system, the user must alter the pro-
gram shunt module to allow the multiplexing of the I/O lines. An optional interface line may be
assigned to the DSO (J 1-6) line.
2.4.1.2 Motor On (J 1-16). This feature is provided for the user to directly control (via the
interface) the DC spindle motor. A low level at the interface turns the spindle motor on. The
spindle takes one second after this line is activated to come up to speed. A one second delay should
occur after motor on and before any reading or writing is attempted. If such a feature is not desir-
able, the spindle motor can be kept on by permanently grounding the Motor On line; however, use
of this feature is recommended to reduce average power consumption and increase overall life of the
disk drive. If the Motor On signal is used, the program shunt module may require changing if the
Head Load with Motor On option is selected.
2.4.1.3 Direction Select (J 1-18). This line controls the direction of travel of the read/write
head. A low level on this line causes the head to move toward the center of the spindle only when
a Step pulse occurs. The Direction Select signal should be stable from 1.0 microsec. before to 1.0
microsec. after the trail ing edge of Step.
2.4.1.4 Step (J1-20). A low pulse on this line, together with Direction Select, initiates a single-
track move of the head. Head movement begins on the trailing edge of this pulse. Minimum pulse
width should be not less than 1.0 microsecond and the maximum pulse repetition rate should be one
pulse every 25 milliseconds.
2.4.1.5 Write Gate (J1-24). A low level on this line enables Composite Write Data to be written
on the diskette. A high (false) level on this line enables the stepper motor logic and Composite Read
Data line so that Read data may be read from the diskette.
2.4.2 OUTPUT LINES
Output signals from disk drive to controller are carried by three lines; Track 00, Index/Sector, and
Write Protect.
2.4.2.1 Track
00'
(J1-26). A low level on this line informs the controller that the position of
the read/write head is at track
~1jJ.
Subsequent step-out pulses are ignored by the disk drive.
2·10