<s>
The	O
MPT8080	B-Device
"	O
Microtutor	O
"	O
is	O
a	O
microprocessor	B-Architecture
trainer	O
based	O
on	O
the	O
Intel	B-General_Concept
8080	I-General_Concept
processor	O
,	O
developed	O
by	O
Limrose	O
Electronics	O
.	O
</s>
<s>
It	O
was	O
designed	O
in	O
the	O
mid-1970s	O
to	O
assist	O
in	O
the	O
understanding	O
of	O
the	O
then-new	O
microprocessors	B-Architecture
.	O
</s>
<s>
Users	O
of	O
the	O
MPT8080	B-Device
enter	O
assembly	B-Language
language	I-Language
programs	O
via	O
binary	O
switches	O
or	O
a	O
hexadecimal	O
keypad	O
.	O
</s>
<s>
While	O
the	O
code	O
executes	O
,	O
the	O
user	O
can	O
observe	O
what	O
is	O
happening	O
on	O
the	O
address	O
,	O
data	O
,	O
and	O
control	O
signals	O
of	O
the	O
microprocessor	B-Architecture
.	O
</s>
<s>
The	O
MPT8080	B-Device
acts	O
like	O
a	O
simulator	B-Application
,	O
in	O
that	O
code	O
can	O
be	O
stepped	O
through	O
one	O
instruction	B-General_Concept
—	O
or	O
each	O
cycle	O
of	O
each	O
individual	O
instruction	B-General_Concept
—	O
at	O
a	O
time	O
to	O
observe	O
what	O
is	O
happening	O
.	O
</s>
<s>
The	O
MPT8080	B-Device
has	O
simple	O
input	O
and	O
output	O
,	O
consisting	O
of	O
eight	O
LEDs	O
and	O
eight	O
switches	O
.	O
</s>
<s>
The	O
input	O
and	O
outputs	O
port	O
also	O
have	O
connectors	O
,	O
allowing	O
them	O
to	O
be	O
connected	O
to	O
external	O
signals	O
through	O
accessory	O
patch	O
kits	O
,	O
allowing	O
the	O
MPT8080	B-Device
to	O
control	O
and	O
monitor	O
other	O
circuitry	O
.	O
</s>
<s>
Initially	O
,	O
a	O
Motorola	O
6800-based	O
trainer	O
was	O
developed	O
alongside	O
the	O
Intel	B-General_Concept
8080	I-General_Concept
–	O
based	O
model	O
,	O
but	O
due	O
to	O
technical	O
and	O
operational	O
issues	O
the	O
6800	O
trainer	O
was	O
abandoned	O
.	O
</s>
<s>
As	O
recently	O
as	O
2012	O
,	O
the	O
MPT8080	B-Device
remained	O
in	O
academic	O
use	O
at	O
King	O
's	O
College	O
London	O
,	O
as	O
part	O
of	O
a	O
course	O
in	O
practical	O
physics	O
.	O
</s>
<s>
,	O
the	O
MPT8080	B-Device
was	O
still	O
available	O
for	O
sale	O
.	O
</s>
<s>
The	O
initial	O
version	O
of	O
the	O
MPT8080	B-Device
was	O
designed	O
by	O
Dr.	O
Ravi	O
Raizada	O
,	O
the	O
chief	O
executive	O
officer	O
of	O
Limrose	O
Electronics	O
.	O
</s>
<s>
The	O
second	O
version	O
of	O
the	O
MPT8080	B-Device
,	O
introduced	O
around	O
1980	O
,	O
was	O
designed	O
by	O
Stephen	O
Pickering	O
and	O
replaced	O
the	O
binary	O
switch	O
input	O
with	O
a	O
16-key	O
hexadecimal	O
keypad	O
.	O
</s>
<s>
A	O
trace	O
mode	O
was	O
added	O
to	O
allow	O
single-cycle	O
execution	O
as	O
well	O
as	O
machine	B-General_Concept
cycles	I-General_Concept
;	O
this	O
allowed	O
the	O
user	O
to	O
quickly	O
step	O
through	O
code	O
until	O
reaching	O
the	O
portion	O
of	O
the	O
program	O
in	O
which	O
the	O
user	O
was	O
interested	O
.	O
</s>
<s>
+Features	O
of	O
the	O
MPT8080	B-Device
Version	O
2	O
Processor	O
Intel	B-General_Concept
8080A	I-General_Concept
Memory	O
One	O
kilobyte	O
:	O
Two	O
2114	O
static	O
1K	O
×	O
4-bit	O
RAM	B-Architecture
chips	I-Architecture
State	B-Architecture
machine	I-Architecture
Based	O
on	O
7400	O
series	O
TTL	B-General_Concept
chip	O
;	O
controls	O
data	O
entry	O
and	O
program	O
execution	O
Input	O
Keypad	O
20	O
keys	O
:	O
</s>
<s>
Programs	O
are	O
entered	O
in	O
the	O
MPT8080	B-Device
in	O
data	O
entry	O
mode	O
(	O
"	O
MMLE	O
"	O
)	O
.	O
</s>
<s>
By	O
selecting	O
single-step	O
and	O
single-cycle	O
mode	O
and	O
stepping	O
through	O
a	O
program	O
with	O
the	O
step	O
button	O
,	O
the	O
user	O
can	O
see	O
exactly	O
what	O
happens	O
during	O
every	O
instruction	B-General_Concept
cycle	I-General_Concept
,	O
observing	O
the	O
program	B-General_Concept
counter	I-General_Concept
,	O
data	B-General_Concept
bus	I-General_Concept
and	O
control	O
signals	O
on	O
their	O
corresponding	O
LEDs	O
.	O
</s>
<s>
By	O
selecting	O
single-instruction	O
mode	O
,	O
rather	O
than	O
single-cycle	O
mode	O
,	O
each	O
press	O
of	O
the	O
step	O
button	O
will	O
execute	O
a	O
complete	O
instruction	B-General_Concept
,	O
rather	O
than	O
a	O
single	O
cycle	O
.	O
</s>
<s>
The	O
input/output	O
ports	O
can	O
be	O
used	O
to	O
read	O
external	O
signals	O
and	O
drive	O
output	B-Device
devices	I-Device
like	O
motors	O
and	O
buzzers	O
with	O
little	O
or	O
no	O
additional	O
hardware	O
.	O
</s>
<s>
The	O
system	O
is	O
programmed	O
directly	O
in	O
8080	B-General_Concept
machine	B-Language
code	I-Language
:	O
</s>
