SEMA ELECTRONICS CO.,LTD
FLOPPY DISK DRIVE SPECIFICATION
PAG E 17
MODEL
SFD-321B
5.3 Input Signals
5.3.1 Density Select
This siganl is used to distinguish between 1.6MB and 2MB Mode.
The interface pin No.2 can be used as Density Select Input signal by
attaching 0
Ω
resistor onto "OPA" short plug when the High density media
is inserted. The "HIGH" level desig nates 2MB Mode and the "LOW" level
designates 1.6MB Mode. FDD can tell whether the inserted media is high
or Low de nsity by checking the signal co ming fro m mechanica l switch which
detects the density selecting hole on the media.
5.3.2 Drive Select 0 and 1
Two trace plugs on the PCB, DS0 and DS1 are provided to select which
Drive Select l ine will activate the interface signals for a unique drive in the
daisy chain connection up to two drive units. Drive Select, when activated
logical "LOW", enables all th e I/O lines except Motor On line.
This signal a lso controls the lighten in g of In-Use LED.
Type Contents
2Mode
(2.0 / 1.0MB)
(Non-connection of "OPA")
Automatic S witching
2.0MB : If High density media is in serted.
1.0MB : If Low density media is inserted.
3Mode
(2.0 / 1.6 / 1.0MB)
(Connection of "OPA")
Automatic S witching with "Density Select"
2.0MB : If High density media is in serted
wi th "Density Select" is "HIGH".
1.6MB : If High density media is in serted
wi th "Density Select" is "LOW".
1.0MB : If Low density media is inserted
"Density Select" is not available.
