BASF 6106 - Page 31

.2.
8.
2. WRITE
CIRCUITS
The
write
circuits
encode
serial data
from
the
host
system
to
magnetic
flux
patterns
recor-
ded
on
the
mini
disk.
A
write
operation
is
initiated
by
the
host
system
activating
the
following
input
lines
(see
Fig.
2
-
29 )
•
•
SELECT/
selects
the
drive
and
loads the head
if
no
head
load
option
is
installed.
MOTOR
ON
/
rotates
the
mini
disk.
• WRITE
GATE
/
turns
on
the
write
circuits.
• WRITE
DATA
/
FM-encoded
write
data.
•
HEAD
LOAD
/
loads
the
head
if
head
load
option
is
used.
A simplified
logic
of
the
write
circuits
is
shown on
Fig.
2-30 .
The write circuits
are
activated
by
WRTENA
which is
active
when the
host
system
sends
WRITE
GATE. The
drive
must
be
selected
and not
write
protected. The
FM
data
stream
from
the
host
system
is
divided
by
the
write
flipflop.
The outputs
of
the
write flipflop
alternately
turr on transis-
tor T3
and
T4 (see
Fig.
2-31
).
The
write
current I
w
respectively
I
w
'
which is deter-
mined by
the
resistor
R35
flows
then
alter-
nately
through
the
windings
Vt-\
and
W,.
The
write current
and
erase
current
can be
block-
ed
by the
DC-
control
logic
,
if
a
power failure
have
been
detected.
The
erase
current
1
5
is
turned
on by
transistor
T5
when
ERASENA/
is
low.
DC-
POWER
MOTOR
ON
/
DRIVE
SELECT/
(HEAD
LOAD/)
STEP
/
WRITE
GATE/
WRITE
DATA
/
0,5
sec
M1N H
FIGURE
2
-
29
. WRITE
INITIATE
TIMING