<s>
The	O
MCS-48	B-Device
microcontroller	B-Architecture
series	O
,	O
Intel	O
's	O
first	O
microcontroller	B-Architecture
,	O
was	O
originally	O
released	O
in	O
1976	O
.	O
</s>
<s>
Its	O
first	O
members	O
were	O
8048	B-Device
,	O
8035	B-Device
and	O
8748	B-Device
.	O
</s>
<s>
The	O
8048	B-Device
is	O
probably	O
the	O
most	O
prominent	O
member	O
of	O
the	O
family	O
.	O
</s>
<s>
Initially	O
,	O
this	O
family	O
was	O
produced	O
using	O
NMOS	B-Algorithm
(	O
n-type	O
metal	B-Architecture
–	I-Architecture
oxide	I-Architecture
–	I-Architecture
semiconductor	I-Architecture
)	O
technology	O
.	O
</s>
<s>
In	O
the	O
early	O
1980s	O
,	O
it	O
became	O
available	O
in	O
CMOS	B-Device
technology	O
.	O
</s>
<s>
The	O
MCS-48	B-Device
series	O
has	O
a	O
modified	B-Device
Harvard	I-Device
architecture	I-Device
,	O
with	O
internal	O
or	O
external	O
program	O
ROM	B-Device
and	O
64	O
–	O
256	O
bytes	B-Application
of	O
internal	O
(	O
on-chip	O
)	O
RAM	B-Architecture
.	O
</s>
<s>
The	O
I/O	B-General_Concept
is	O
mapped	O
into	O
its	O
own	O
address	B-General_Concept
space	I-General_Concept
,	O
separate	O
from	O
programs	O
and	O
data	O
.	O
</s>
<s>
Though	O
the	O
MCS-48	B-Device
series	O
was	O
eventually	O
replaced	O
by	O
the	O
very	O
successful	O
MCS-51	B-Architecture
series	O
,	O
it	O
remained	O
quite	O
popular	O
even	O
by	O
the	O
year	O
2000	O
due	O
to	O
its	O
low	O
cost	O
,	O
wide	O
availability	O
,	O
memory-efficient	O
one-byte	O
instruction	B-General_Concept
set	I-General_Concept
,	O
and	O
mature	O
development	O
tools	O
.	O
</s>
<s>
The	O
8049	B-Device
has	O
2KB	O
of	O
masked	B-Device
ROM	I-Device
(	O
the	O
8748	B-Device
and	O
8749	B-Device
had	O
EPROM	B-General_Concept
)	O
that	O
can	O
be	O
replaced	O
with	O
a	O
4KB	O
external	O
ROM	B-Device
,	O
as	O
well	O
as	O
128bytes	O
of	O
RAM	B-Architecture
and	O
27I/O	O
ports	O
.	O
</s>
<s>
The	O
microcontroller	B-Architecture
's	O
oscillator	O
block	O
divides	O
the	O
incoming	O
clock	O
into	O
15	O
internal	O
phases	O
,	O
thus	O
with	O
its	O
11MHz	O
max	O
.	O
</s>
<s>
Some	O
70%	O
of	O
instructions	O
are	O
single	O
byte/cycle	O
ones	O
,	O
but	O
30%	O
need	O
two	O
cycles	O
and/or	O
two	O
bytes	B-Application
,	O
so	O
the	O
raw	O
performance	O
would	O
be	O
closer	O
to	O
0.5MIPS	O
.	O
</s>
<s>
+Microcontroller	O
Device	O
Internal	O
Memory	O
Remarks	O
8020	O
1K	O
×	O
8	O
ROM	B-Device
64	O
×	O
8	O
RAM	B-Architecture
subset	O
of	O
8048	B-Device
,	O
20	O
pins	O
,	O
only	O
13	O
I/O	B-General_Concept
lines	O
8021	B-Device
1K	O
×	O
8	O
ROM	B-Device
64	O
×	O
8	O
RAM	B-Architecture
subset	O
of	O
8048	B-Device
,	O
28	O
pins	O
,	O
21	O
I/O	B-General_Concept
lines	O
8022	B-Device
2K	O
×	O
8	O
ROM	B-Device
64	O
×	O
8	O
RAM	B-Architecture
subset	O
of	O
8048	B-Device
,	O
A/D	O
-converter	O
8035	B-Device
none	O
64	O
×	O
8	O
RAM	B-Architecture
8038	O
none	O
64	O
×	O
8	O
RAM	B-Architecture
8039	B-Device
none	O
128	O
×	O
8	O
RAM	B-Architecture
8040	B-Device
none	O
256	O
×	O
8	O
RAM	B-Architecture
8048	B-Device
1K	O
×	O
8	O
ROM	B-Device
64	O
×	O
8	O
RAM	B-Architecture
27×	O
I/O	B-General_Concept
ports	O
8049	B-Device
2K	O
×	O
8	O
ROM	B-Device
128	O
×	O
8	O
RAM	B-Architecture
27×	O
I/O	B-General_Concept
ports	O
8050	B-Device
4K	O
x	O
8	O
ROM	B-Device
256	O
×	O
8	O
RAM	B-Architecture
8648	O
1K	O
×	O
8	O
OTP	O
EPROM	B-General_Concept
64	O
×	O
8	O
RAM	B-Architecture
Factory	O
OTP	O
EPROM	B-General_Concept
8748	B-Device
1K	O
×	O
8	O
EPROM	B-General_Concept
64	O
×	O
8	O
RAM	B-Architecture
2×	O
8-bit	O
timers	O
,	O
27×	O
I/O	B-General_Concept
ports	O
8749	B-Device
2K	O
×	O
8	O
EPROM	B-General_Concept
128	O
×	O
8	O
RAM	B-Architecture
2×	O
8-bit	O
timers	O
,	O
27×	O
I/O	B-General_Concept
ports	O
87P50	O
ext	O
.	O
</s>
<s>
The	O
MCS-48	B-Device
series	O
was	O
commonly	O
used	O
in	O
computer	O
and	O
terminal	O
keyboards	O
,	O
converting	O
key	O
presses	O
into	O
protocols	O
that	O
can	O
be	O
understood	O
by	O
digital	O
circuits	O
.	O
</s>
<s>
The	O
8048	B-Device
has	O
been	O
used	O
in	O
this	O
application	O
since	O
its	O
introduction	O
in	O
1978	O
.	O
</s>
<s>
The	O
Tandy/Radio	O
Shack	O
TRS-80	B-Device
Model	I-Device
II	I-Device
,	O
released	O
in	O
1979	O
,	O
used	O
the	O
8021	B-Device
in	O
its	O
keyboard	O
.	O
</s>
<s>
The	O
8021	B-Device
processor	O
scans	O
the	O
key	O
matrix	O
,	O
converts	O
switch	O
closures	O
to	O
an	O
8-bit	O
code	O
and	O
then	O
transmits	O
that	O
code	O
serially	O
to	O
the	O
keyboard	O
interface	O
on	O
the	O
main	O
system	O
.	O
</s>
<s>
The	O
8021	B-Device
will	O
also	O
accept	O
commands	O
to	O
turn	O
indicator	O
LEDs	O
on	O
or	O
off	O
.	O
</s>
<s>
The	O
8021	B-Device
was	O
also	O
used	O
in	O
the	O
keyboards	O
for	O
the	O
TRS-80	O
Model	O
12	O
,	O
12B	O
,	O
16	O
,	O
16B	O
and	O
the	O
Tandy	O
6000/6000HD	O
.	O
</s>
<s>
The	O
original	O
IBM	B-Device
PC	I-Device
keyboard	I-Device
used	O
an	O
8048	B-Device
as	O
its	O
internal	O
microcontroller	B-Architecture
.	O
</s>
<s>
The	O
PC	B-Operating_System
AT	I-Operating_System
replaced	O
the	O
PC	O
's	O
Intel	B-Device
8255	I-Device
peripheral	O
interface	O
chip	O
at	O
I/O	B-General_Concept
port	O
addresses	O
with	O
an	O
8042	B-Device
accessible	O
through	O
port	O
addresses	O
and	O
.	O
</s>
<s>
As	O
well	O
as	O
managing	O
the	O
keyboard	O
interface	O
,	O
the	O
8042	B-Device
controlled	O
the	O
A20	B-Device
line	I-Device
gating	O
function	O
for	O
the	O
AT	O
's	O
Intel	B-General_Concept
80286	I-General_Concept
CPU	O
and	O
could	O
be	O
commanded	O
by	O
software	O
to	O
reset	O
the	O
80286	B-General_Concept
(	O
unlike	O
the	O
80386	B-General_Concept
and	O
later	O
processors	O
,	O
the	O
80286	B-General_Concept
had	O
no	O
way	O
of	O
switching	O
from	O
protected	B-Application
mode	I-Application
back	O
to	O
real	B-Application
mode	I-Application
except	O
by	O
being	O
reset	O
)	O
.	O
</s>
<s>
Later	O
PC	O
compatibles	O
integrate	O
the	O
8042	B-Device
's	O
functions	O
into	O
their	O
super	B-Device
I/O	I-Device
devices	O
.	O
</s>
<s>
The	O
8048	B-Device
was	O
used	O
in	O
the	O
Magnavox	B-Application
Odyssey²	I-Application
video	B-Device
game	I-Device
console	I-Device
,	O
the	O
Korg	O
Trident	O
series	O
,	O
and	O
the	O
Korg	O
Poly-61	O
,	O
Roland	O
Jupiter-4	O
and	O
Roland	O
ProMars	O
analog	O
synthesizers	O
.	O
</s>
<s>
The	O
Sinclair	B-Device
QL	I-Device
used	O
the	O
closely	O
related	O
Intel	B-Device
8049	I-Device
to	O
manage	O
its	O
keyboard	O
,	O
joystick	O
ports	O
,	O
RS-232	O
inputs	O
and	O
audio	O
.	O
</s>
<s>
The	O
ROM-less	O
8035	B-Device
variant	O
was	O
used	O
in	O
Nintendo	O
's	O
arcade	O
game	O
Donkey	B-Application
Kong	I-Application
to	O
generate	O
the	O
background	O
music	O
.	O
</s>
<s>
These	O
were	O
the	O
first	O
microcontrollers	B-Architecture
with	O
an	O
integrated	O
I²C-interface	O
and	O
were	O
used	O
in	O
the	O
first	O
Philips	O
(	O
Magnavox	O
in	O
the	O
US	O
)	O
Compact	B-Device
Disc	I-Device
players	I-Device
(	O
e.g.	O
</s>
