Apple IIe - Apple IIe Peripherals and Connections

Introduction
to
the
Apple
lie
17
loaded
from
a
tape
cassette,
a disk drive,
or
the
keyboard,
it
is
stored
in RAM. For
example
,
when
a
program
is
loaded
from
the
Apple
Disk
II
,
it
will
be
stored
in RAM.
Dynamic and
Static
RAM
There
are
two
different
types
of
RAM
memory;
dynamic RAM
and
static RAM.
Dynamic RAM
can
only
hold
the
data
it
is
storing
for a few
milliseconds.
Therefore,
any
data
being
stored
in
dynamic
RAM
must
constantly
be
rewritten
or
refreshed.
This
dynamic
RAM refresh
function
must
be
a
part
of
the
support
logic
when
the
dynamic
RAM
memory
is
designed.
Static RAM
is
more
expensive
than
dynamic
RAM.
However,
once
data
has
been
written
into
static RAM, it
wi
ll
be
retained
as
long
as
power
is
supplied.
Apple
lie
Power
Supply
~
The
Apple
lle's
power
supply
is
located
on
the
left
side
of
the
inside
of
the
unit
as
shown
in Illustration
1-2.
The
power
supply
will supply
four
voltages:
+Sv
, -Sv, +12.0v,
and
-12v.
The
Apple's
main
power
cord
plugs
into
the
power
supply
on
the
back
of
the
Apple
.
The
Apple's
power-on
switch
is
also
located
on
the
back
of
the
power
supply.
This
is
pictured
in
Illustration
1-3.
Some
Apple's
have
a
power
supply
with a switch
which
allows
the
user
to
select
either
110
or
220 volts.
Apple
lie
Speaker
As
pictured
in
Illustration
1-2,
the
Apple
I
le's
speaker
is
located
inside
the
case
on
the
lower
left
hand
side.
The
speaker
is
connected
to
the
Apple
so
that
a
program
can
be
used
to
create
sounds
on
it.
The
Apple
lle's
speaker
is
controlled
by a
soft switch.
Soft
switches
have
two
states (ex.
in/out;
on/off
;
text/graphics).
By
addressing
a special
memory
location
associated
with
the
soft
switch, a
program
can
change
the
state
of
the
switch.