<s>
The	O
TK-80	B-Device
( μCOM	O
Training	O
Kit	O
TK-80	B-Device
)	O
was	O
an	O
8080-based	O
single-board	B-Device
computer	I-Device
kit	O
developed	O
by	O
Nippon	O
Electric	O
Company	O
(	O
NEC	O
)	O
in	O
1976	O
.	O
</s>
<s>
It	O
was	O
successful	O
among	O
hobbyists	O
in	O
late	O
1970s	O
in	O
Japan	O
,	O
due	O
to	O
its	O
reasonable	O
price	O
and	O
an	O
expensive	O
computer	B-General_Concept
terminal	I-General_Concept
not	O
being	O
required	O
.	O
</s>
<s>
In	O
the	O
1970s	O
,	O
the	O
Semiconductor	O
Division	O
developed	O
several	O
microprocessors	B-Architecture
including	O
Intel	O
compatible	O
processors	O
,	O
and	O
in	O
1976	O
got	O
a	O
second-source	O
agreement	O
with	O
Intel	O
to	O
produce	O
the	O
8080	B-General_Concept
microprocessor	I-General_Concept
legally	O
.	O
</s>
<s>
In	O
Japan	O
,	O
few	O
engineers	O
were	O
interested	O
in	O
microprocessors	B-Architecture
,	O
and	O
NEC	O
salesmen	O
could	O
n't	O
find	O
what	O
kind	O
of	O
demand	O
would	O
make	O
much	O
profit	O
.	O
</s>
<s>
In	O
February	O
1976	O
,	O
the	O
Semiconductor	O
and	O
Integrated	O
Circuit	O
Sales	O
Division	O
formed	O
the	O
Microcomputer	O
Sales	O
Section	O
,	O
and	O
began	O
to	O
provide	O
development	O
environments	O
for	O
their	O
microprocessors	B-Architecture
.	O
</s>
<s>
However	O
,	O
they	O
visited	O
customers	O
and	O
explained	O
,	O
but	O
it	O
was	O
difficult	O
for	O
them	O
to	O
understand	O
how	O
to	O
use	O
a	O
microprocessor	B-Architecture
.	O
</s>
<s>
Based	O
on	O
this	O
kit	O
,	O
the	O
TK-80	B-Device
was	O
developed	O
for	O
general	O
engineers	O
and	O
aimed	O
to	O
create	O
a	O
demand	O
for	O
microprocessors	B-Architecture
outside	O
the	O
industrial	O
field	O
.	O
</s>
<s>
Gotō	O
mainly	O
designed	O
the	O
TK-80	B-Device
,	O
and	O
did	O
the	O
detailed	O
design	O
work	O
.	O
</s>
<s>
Gotō	O
got	O
an	O
idea	O
from	O
a	O
photo	O
of	O
the	O
KIM-1	B-Device
.	O
</s>
<s>
The	O
KIM-1	B-Device
can	O
monitor	O
and	O
show	O
the	O
current	O
address	O
by	O
the	O
software	O
,	O
but	O
the	O
display	O
disappears	O
when	O
the	O
CPU	O
is	O
hanging	O
.	O
</s>
<s>
The	O
TK-80	B-Device
has	O
the	O
Dynamic	O
Display	O
using	O
the	O
555	O
timer	O
IC	O
and	O
interrupt	O
the	O
CPU	O
,	O
it	O
can	O
always	O
show	O
the	O
current	O
address	O
.	O
</s>
<s>
In	O
addition	O
,	O
the	O
TK-80	B-Device
has	O
a	O
CMOS	O
battery	O
.	O
</s>
<s>
He	O
decided	O
to	O
document	O
its	O
manual	O
with	O
a	O
circuit	B-Application
diagram	I-Application
and	O
assembly	B-Language
code	I-Language
of	O
the	O
debug	B-General_Concept
monitor	I-General_Concept
,	O
influenced	O
by	O
the	O
PDP-8	B-Device
which	O
was	O
an	O
open	B-Architecture
architecture	I-Architecture
and	O
was	O
used	O
as	O
an	O
IC	O
tester	O
at	O
NEC	O
.	O
</s>
<s>
The	O
TK-80	B-Device
came	O
out	O
on	O
August	O
3	O
,	O
1976	O
.	O
</s>
<s>
The	O
TK-80	B-Device
was	O
sold	O
more	O
than	O
2,000	O
units	O
per	O
month	O
,	O
despite	O
200	O
units	O
expected	O
.	O
</s>
<s>
Soon	O
after	O
its	O
success	O
,	O
other	O
Japanese	O
microprocessor	B-Architecture
manufacturers	O
developed	O
an	O
evaluation	O
kit	O
for	O
their	O
microprocessor	B-Architecture
.	O
</s>
<s>
Also	O
,	O
some	O
computer	O
magazines	O
were	O
founded	O
,	O
the	O
ASCII	O
,	O
the	O
I/O	O
,	O
the	O
and	O
the	O
RAM	B-Architecture
.	O
</s>
<s>
When	O
Kato	O
worked	O
for	O
the	O
help	O
desk	O
at	O
Bit-INN	O
,	O
a	O
doctor	O
asked	O
him	O
how	O
to	O
use	O
the	O
TK-80	B-Device
for	O
calculating	O
medical	O
costs	O
on	O
the	O
point	O
system	O
,	O
and	O
a	O
store	O
manager	O
asked	O
him	O
whether	O
it	O
could	O
process	O
sales	O
information	O
.	O
</s>
<s>
He	O
noticed	O
users	O
were	O
trying	O
to	O
use	O
the	O
TK-80	B-Device
as	O
a	O
computer	O
rather	O
than	O
a	O
training	O
kit	O
.	O
</s>
<s>
However	O
,	O
the	O
TK-80	B-Device
lacked	O
memory	O
and	O
expandability	O
to	O
use	O
for	O
practical	O
purposes	O
.	O
</s>
<s>
Its	O
BASIC	O
was	O
designed	O
to	O
fit	O
in	O
4	O
KB	O
of	O
ROM	B-Device
,	O
had	O
the	O
same	O
as	O
Li-Chen	O
Wang	O
's	O
Tiny	B-Language
BASIC	I-Language
except	O
some	O
differences	O
in	O
functions	O
and	O
statements	O
.	O
</s>
<s>
This	O
led	O
to	O
the	O
development	O
of	O
a	O
new	O
machine	O
which	O
became	O
the	O
PC-8001	B-Device
.	O
</s>
<s>
In	O
Japan	O
,	O
the	O
Altair	B-Architecture
8800	I-Architecture
was	O
sold	O
in	O
1975	O
,	O
but	O
not	O
successful	O
due	O
to	O
its	O
high	O
brokerage	O
fee	O
.	O
</s>
<s>
Neither	O
was	O
the	O
Apple	B-Device
II	I-Device
nor	O
the	O
Commodore	B-Device
PET	I-Device
.	O
</s>
<s>
Single-board	B-Device
computers	I-Device
had	O
been	O
popular	O
until	O
the	O
successor	O
PC-8001	B-Device
came	O
out	O
in	O
1979	O
.	O
</s>
<s>
It	O
contained	O
the	O
NEC	B-Device
μPD8080AF	I-Device
(	O
2	O
MHz	O
)	O
,	O
fully	O
compatible	O
with	O
the	O
Intel	B-General_Concept
8080A	I-General_Concept
.	O
</s>
<s>
Up	O
to	O
1	O
KB	O
expandable	O
)	O
of	O
ROM	B-Device
,	O
and	O
512	O
B	O
(	O
Max	O
.	O
</s>
<s>
Up	O
to	O
1	O
KB	O
expandable	O
)	O
of	O
RAM	B-Architecture
.	O
</s>
<s>
It	O
included	O
a	O
keyboard	O
,	O
a	O
backplane	B-Architecture
and	O
an	O
expansion	O
board	O
for	O
the	O
TK-80	B-Device
with	O
5	O
KB	O
of	O
RAM	B-Architecture
and	O
12	O
KB	O
of	O
ROM	B-Device
.	O
</s>
<s>
It	O
contained	O
the	O
μPD8085AC	O
processor	O
(	O
2.4576	O
MHz	O
)	O
and	O
has	O
a	O
system	O
configuration	O
that	O
is	O
considered	O
to	O
some	O
extent	O
for	O
compatibility	O
with	O
the	O
TK-80	B-Device
.	O
</s>
<s>
Up	O
to	O
8	O
KB	O
expandable	O
)	O
of	O
ROM	B-Device
,	O
1	O
KB	O
of	O
RAM	B-Architecture
,	O
while	O
the	O
board	O
size	O
was	O
310	O
×	O
220	O
mm	O
.	O
</s>
<s>
The	O
PDA-80	O
was	O
a	O
development	O
platform	O
for	O
NEC	O
's	O
microprocessors	B-Architecture
.	O
</s>
<s>
It	O
had	O
the	O
μPD8080A	O
processor	O
,	O
8	O
KB	O
of	O
RAM	B-Architecture
,	O
a	O
teleprinter	O
interface	O
and	O
a	O
self	O
assembler	B-Language
for	O
its	O
processor	O
.	O
</s>
