Specifications
Table
2-16.
Supported
Floppy
Formats
Capacity Tracks Drive Size Data Rate
DOS
Version
360K
40
5-1/4"
250
KHz
2.1+
1.2M
80
5-1/4"
500
KHz
3.0+
720K
80
3-1/2"
250
KHz
3.2+
1.44M
80
3-1/2"
500
KHz
3.3+
~
you
can
see from Table 2-16, nearly any type
of
soft-sectored, single
or
double-sided, 40
or
80
track,
mini
or
micro
floppy disk drive is usable. Naturally,
the
higher
the
quality
of
the
drives you use,
the
better
your system's reliability.
Here
are
some considerations regarding the selection, conftgUfation,
and
connection
of
floppy
drives
to
the
Little
Board/PC:
.
•
The
drives used must
be
compatible with the board's floppy disk interface.
In
general,
any standard
PC
or
AT
compatible 5-1/4"
or
3-1/2" floppy drive will work. 7201(, 1.2M
or
1.44M floppy drives
used
must
provide
an
IBM
PC/AT
compatible
"disk change"
signal.
Any
5-1/4"
AT
compatible
1.2M drive
can
be
expected
to
supply
the
required
signal.
The
following
3-1/2"
720K
and
1.44M floppy drives
are
known
to
provide
the
required signal:
Brand
Fujitsu
Teac
Panasonic
Mitsubishi
720KDrive
M532K-19A
FD-235-F-l00U
JU-253-09P
MF353C-12UJ
1.44MDrive
M2537K-19A
FD-235-HF-I0I-U
JU-257-14PF
MF-355C-12UJ
•
High
quality,
DC
servo direct drive
motor
floppy disk drives
are
recommended.
•
Any
combination
of
supported drives
can
be
used. See Table 2-14.
•
The
computer
board
must
be
jumpered
for
the
number
and
type
of
floppy drives
to
be
used. (Details follow.)
•
The
drives
must
be
jumpered
to
the
second
drive select.
Use
a floppy cable
with
a
segment
of
wires twisted, as is
the
usual practice
in
PC
and
AT
compatible systems.
• Resistive terminations should
be
installed only
on
the drive connected
to
the
last inter-
face cable connector
(farthest
from
the
computer).
•
When
using drives with a
Head
Load
option,
jumper
the drive for "head
load
with
motor
on"
rather
than "head load with drive select."
• Sometimes a thin metal shield is required when mounting
the
board
directly
to
a floppy
drive
due
to
electromagnetic interactions.
Note
that
the
Little
Board/PC's
ROM-BIOS
provides dual-capacity
use
of
1.2M
or
1.44M
drive:
that
is, 360K floppies
can
be
read
in a 1.2M drive, and 720K floppies
can
be
read
in
a
1.44M drive. However, it is not recommended that a low-density floppy
be
written in a high-
density drive, as incomplete erasure may occur.
2-17