SEMA ELECTRONICS CO.,LTD
FLOPPY DISK DRIVE SPECIFICATION
PAGE 17
MODEL SFD-321B
5.3 Input Signals5.3.1 Density Select
This siganl is used to distinguish between 1.6MB and 2MB Mode.
The interface pin No.2 can beused as Density Select Input signal by
attaching 0 Ωresistor onto "OPA" short plug when the High density media
is inserted. The "HIGH" level designates 2MB Mode and the "LOW" level
designates 1.6MB Mode. FDD can tell whether the inserted media is high
or Low density by checking the signal coming from mechanical switch which
detects the density selecting hole on the media.
5.3.2 Drive Select 0 and 1
Two trace plugson the PCB, DS0 and DS1 are provided to select which
Drive Se lect line will activa te the interfa ce sign als for a uniq ue drive in the
daisy chain connection up to two drive units. Drive Select, when activated
logical "LOW", enables all the I/O lines except Motor On line.
This signal also controls the lightening of In-Use LED.
Type Contents
2Mode
(2.0 / 1.0MB)
(Non-connection of "OPA")
Automatic Switch ing
2.0MB : If High density media is inserted.
1.0MB : If Low density media is inserted.
3Mode
(2.0 / 1.6 / 1.0M B)
(Connection of "OPA")
Automatic Sw itching with " Density Selec t"
2.0MB : If High density media is inserted
with "Density Select" is "HIG H".
1.6MB : If High density media is inserted
with "Density Select" is "L OW".
1.0MB : If Low density media is inserted
"Density Select" is not available.