<s>
The	O
RadioShack	O
TRS-80	B-Device
Color	I-Device
Computer	I-Device
,	O
later	O
marketed	O
as	O
the	O
Tandy	B-Device
Color	I-Device
Computer	I-Device
and	O
sometimes	O
nicknamed	O
the	O
CoCo	O
,	O
is	O
a	O
line	O
of	O
home	O
computers	O
developed	O
and	O
sold	O
by	O
Tandy	O
Corporation	O
.	O
</s>
<s>
Despite	O
sharing	O
a	O
name	O
with	O
the	O
earlier	O
TRS-80	B-Device
,	O
the	O
Color	B-Device
Computer	I-Device
is	O
a	O
completely	O
different	O
,	O
incompatible	O
system	O
and	O
a	O
radical	O
departure	O
in	O
design	O
and	O
compatibility	O
with	O
its	O
Motorola	B-Device
6809E	I-Device
processor	O
rather	O
than	O
the	O
Zilog	B-General_Concept
Z80	I-General_Concept
earlier	O
models	O
were	O
built	O
around	O
.	O
</s>
<s>
The	O
Tandy	B-Device
Color	I-Device
Computer	I-Device
line	O
started	O
in	O
1980	O
with	O
what	O
is	O
now	O
called	O
the	O
Color	B-Device
Computer	I-Device
1	O
.	O
</s>
<s>
It	O
was	O
followed	O
by	O
the	O
Color	B-Device
Computer	I-Device
2	O
in	O
1983	O
,	O
then	O
the	O
Color	B-Device
Computer	I-Device
3	O
in	O
1986	O
.	O
</s>
<s>
The	O
Color	B-Device
Computer	I-Device
3	O
was	O
discontinued	O
in	O
1991	O
.	O
</s>
<s>
All	O
Color	B-Device
Computer	I-Device
models	O
shipped	O
with	O
Color	B-Language
BASIC	I-Language
,	O
an	O
implementation	O
of	O
Microsoft	B-Language
BASIC	I-Language
,	O
in	O
ROM	B-Device
.	O
</s>
<s>
Variants	O
of	O
the	O
OS-9	B-Operating_System
multitasking	O
operating	O
system	O
were	O
available	O
from	O
third	O
parties	O
.	O
</s>
<s>
Tandy	O
Corporation	O
announced	O
the	O
TRS-80	B-Device
Color	I-Device
Computer	I-Device
in	O
July	O
1980	O
to	O
compete	O
with	O
the	O
inexpensive	O
and	O
popular	O
VIC-20	B-Device
.	O
</s>
<s>
The	O
Color	B-Device
Computer	I-Device
is	O
a	O
completely	O
different	O
design	O
than	O
the	O
Zilog	O
Z80-based	O
TRS-80	B-Device
models	O
.	O
</s>
<s>
BYTE	B-Application
wrote	O
,	O
"	O
The	O
only	O
similarity	O
between	O
[	O
the	O
two	O
computers ]	O
is	O
the	O
name	O
"	O
.	O
</s>
<s>
The	O
TRS-80	B-Device
Color	I-Device
Computer	I-Device
derives	O
from	O
an	O
"	O
experimental	O
videotext	O
project	O
by	O
the	O
Kentucky	O
Cooperative	O
Extension	O
Service	O
and	O
the	O
University	O
of	O
Kentucky	O
College	O
of	O
Agriculture	O
"	O
in	O
1977	O
.	O
</s>
<s>
The	O
initial	O
goal	O
of	O
this	O
project	O
,	O
called	O
"	O
Green	O
Thumb	O
"	O
,	O
was	O
to	O
create	O
a	O
low	O
cost	O
Videotex	B-Operating_System
terminal	O
for	O
farmers	O
,	O
ranchers	O
,	O
and	O
others	O
in	O
the	O
agricultural	O
industry	O
.	O
</s>
<s>
Motorola	O
's	O
MC6847	B-General_Concept
Video	B-General_Concept
Display	I-General_Concept
Generator	I-General_Concept
(	O
VDG	O
)	O
chip	O
was	O
released	O
about	O
the	O
time	O
the	O
joint	O
venture	O
started	O
.	O
</s>
<s>
The	O
1978	O
prototype	O
"	O
Green	O
Thumb	O
"	O
terminal	O
used	O
the	O
MC6847	B-General_Concept
and	O
the	O
Motorola	B-Device
6809	I-Device
microprocessor	O
.	O
</s>
<s>
The	O
SAM	O
,	O
VDG	O
,	O
and	O
6809	B-Device
were	O
used	O
as	O
the	O
core	O
of	O
the	O
AgVision	O
terminal	O
.	O
</s>
<s>
It	O
was	O
also	O
sold	O
through	O
Radio	O
Shack	O
stores	O
as	O
the	O
VideoTex	B-Operating_System
terminal	O
around	O
1980	O
.	O
</s>
<s>
The	O
VideoTex	B-Operating_System
terminal	O
provided	O
the	O
foundation	O
for	O
a	O
general-purpose	O
home	O
computer	O
.	O
</s>
<s>
The	O
internal	O
modem	B-Application
was	O
removed	O
,	O
and	O
I/O	O
ports	O
for	O
cassette	O
storage	O
,	O
serial	O
I/O	O
,	O
and	O
joysticks	O
were	O
provided	O
.	O
</s>
<s>
An	O
expansion	O
connector	O
was	O
added	O
to	O
the	O
right	O
side	O
of	O
the	O
case	O
for	O
future	O
enhancements	O
and	O
ROM	B-Protocol
cartridges	I-Protocol
(	O
"	O
Program	O
Paks	O
"	O
)	O
.	O
</s>
<s>
A	O
sticker	O
indicating	O
the	O
amount	O
of	O
installed	O
memory	O
in	O
the	O
machine	O
covers	O
the	O
hole	O
where	O
the	O
Modem	B-Application
's	O
LED	O
"	O
DATA	O
"	O
indicator	O
had	O
been	O
.	O
</s>
<s>
On	O
July	O
31	O
,	O
1980	O
,	O
Tandy	O
announced	O
the	O
TRS-80	B-Device
Color	I-Device
Computer	I-Device
,	O
which	O
shares	O
the	O
same	O
case	O
,	O
keyboard	O
,	O
and	O
layout	O
as	O
the	O
AgVision/VideoTex	O
terminals	O
.	O
</s>
<s>
Although	O
the	O
company	O
's	O
Ed	O
Juge	O
said	O
in	O
1981	O
that	O
the	O
Color	B-Device
Computer	I-Device
was	O
"	O
our	O
entry	O
into	O
the	O
home-computer	O
market	O
"	O
,	O
he	O
described	O
it	O
as	O
"	O
for	O
serious	O
professionals	O
"	O
,	O
stating	O
that	O
a	O
word	O
processor	O
and	O
spreadsheet	O
would	O
soon	O
be	O
available	O
.	O
</s>
<s>
The	O
initial	O
model	O
(	O
catalog	O
number	O
26-3001	O
)	O
shipped	O
with	O
4	O
KB	O
of	O
Dynamic	O
Random	O
Access	O
Memory	O
(	O
DRAM	O
)	O
and	O
in	O
ROM	B-Device
.	O
</s>
<s>
The	O
original	O
version	O
of	O
the	O
Color	B-Device
Computer	I-Device
sports	O
a	O
large	O
silver-gray	O
case	O
with	O
a	O
calculator-like	O
chiclet	B-Device
keyboard	I-Device
and	O
was	O
available	O
with	O
memory	O
sizes	O
of	O
4K	O
(	O
26-3001	O
)	O
,	O
16K	O
(	O
26-3002	O
)	O
,	O
or	O
32K	O
(	O
26-3003	O
)	O
.	O
</s>
<s>
Versions	O
with	O
at	O
least	O
16K	O
of	O
memory	O
installed	O
shipped	O
with	O
standard	O
Microsoft	B-Language
Color	I-Language
Basic	I-Language
or	O
(	O
optionally	O
)	O
Extended	B-Language
Color	I-Language
BASIC	I-Language
.	O
</s>
<s>
Early	O
versions	O
of	O
the	O
CoCo	O
1	O
have	O
a	O
black	O
keyboard	O
surround	O
,	O
the	O
TRS-80	B-Device
nameplate	O
above	O
the	O
keyboard	O
to	O
the	O
left	O
side	O
,	O
and	O
a	O
RAM	O
badge	O
(	O
"	O
button	O
"	O
)	O
affixed	O
on	O
the	O
top	O
and	O
right	O
side	O
of	O
the	O
case	O
.	O
</s>
<s>
Later	O
versions	O
removed	O
the	O
black	O
keyboard	O
surround	O
and	O
RAM	O
button	O
,	O
and	O
moved	O
the	O
TRS-80	B-Device
nameplate	O
to	O
the	O
mid-line	O
of	O
the	O
case	O
.	O
</s>
<s>
The	O
computer	O
is	O
based	O
on	O
a	O
single	O
printed-circuit	O
board	O
with	O
all	O
semiconductors	O
manufactured	O
by	O
Motorola	O
including	O
the	O
MC6809E	O
CPU	O
,	O
MC6847	B-General_Concept
VDG	O
,	O
MC6883	O
SAM	O
,	O
and	O
RAM	O
,	O
which	O
consists	O
of	O
2104	O
(	O
4Kx1	O
)	O
chips	O
(	O
4K	O
models	O
)	O
or	O
4116	O
(	O
16Kx1	O
)	O
chips	O
(	O
16K	O
models	O
)	O
.	O
</s>
<s>
Radio	O
Shack	O
could	O
upgrade	O
all	O
versions	O
that	O
shipped	O
with	O
standard	O
Color	B-Language
BASIC	I-Language
to	O
Extended	B-Language
Color	I-Language
BASIC	I-Language
,	O
developed	O
by	O
Microsoft	O
,	O
for	O
$99	O
.	O
</s>
<s>
BYTE	B-Application
wrote	O
in	O
1981	O
that	O
through	O
Extended	B-Language
Color	I-Language
BASIC	I-Language
,	O
Radio	O
Shack	O
"	O
has	O
released	O
the	O
first	O
truly	O
easy-to-use	O
and	O
inexpensive	O
system	O
that	O
generates	O
full-color	O
graphics	O
"	O
.	O
</s>
<s>
In	O
late	O
1982	O
,	O
a	O
version	O
of	O
the	O
Color	B-Device
Computer	I-Device
with	O
a	O
white	O
case	O
,	O
called	O
the	O
TDP	O
System	O
100	O
,	O
was	O
distributed	O
by	O
RCA	O
and	O
sold	O
through	O
non-Tandy	O
stores	O
.	O
</s>
<s>
Except	O
for	O
the	O
nameplate	O
and	O
case	O
,	O
it	O
is	O
identical	O
to	O
the	O
Color	B-Device
Computer	I-Device
.	O
</s>
<s>
This	O
ventilation	O
scheme	O
carried	O
over	O
to	O
the	O
CoCo	B-Device
2	I-Device
.	O
</s>
<s>
The	O
CoCo	B-Device
2	I-Device
was	O
sold	O
in	O
16K	O
and	O
64K	O
models	O
.	O
</s>
<s>
A	O
redesigned	O
5-volt	O
disk	O
controller	O
was	O
introduced	O
with	O
its	O
own	O
new	O
Disk	O
BASIC	O
ROM	B-Device
(	O
v1.1	O
)	O
.	O
</s>
<s>
This	O
allows	O
the	O
use	O
of	O
software	O
on	O
copy	O
protected	O
disks	O
or	O
third-party	O
operating	O
systems	O
,	O
chiefly	O
OS-9	B-Operating_System
.	O
</s>
<s>
The	O
final	O
significant	O
change	O
in	O
the	O
life	O
of	O
the	O
CoCo	B-Device
2	I-Device
(	O
models	O
26-3134B	O
,	O
26-3136B	O
,	O
and	O
26-3127B	O
;	O
16	O
KB	O
standard	O
,	O
16	O
KB	O
extended	O
,	O
and	O
64	O
KB	O
extended	O
respectively	O
)	O
was	O
to	O
use	O
the	O
enhanced	O
VDG	O
,	O
the	O
MC6847T1	O
,	O
allowing	O
lowercase	O
characters	O
and	O
changing	O
the	O
text	O
screen	O
border	O
color	O
.	O
</s>
<s>
Midway	O
during	O
the	O
production	O
run	O
of	O
these	O
models	O
,	O
the	O
nameplate	O
was	O
changed	O
from	O
"	O
Radio	B-Device
Shack	I-Device
TRS-80	I-Device
Color	B-Device
Computer	I-Device
2	O
"	O
to	O
"	O
Tandy	B-Device
Color	I-Device
Computer	I-Device
2	O
"	O
.	O
</s>
<s>
Creative	B-General_Concept
Computing	I-General_Concept
wrote	O
in	O
December	O
1984	O
that	O
the	O
Color	B-Device
Computer	I-Device
was	O
the	O
best	O
educational	O
computer	O
under	O
$1000	O
.	O
</s>
<s>
By	O
1985	O
,	O
Color	B-Device
Computer	I-Device
users	O
worried	O
that	O
the	O
company	O
would	O
abandon	O
their	O
computer	O
in	O
favor	O
of	O
the	O
Tandy	O
1000	O
.	O
</s>
<s>
Tandy	O
executive	O
Ed	O
Juge	O
stated	O
that	O
year	O
that	O
"	O
No	O
home	O
computer	O
on	O
the	O
market	O
today	O
has	O
the	O
potential	O
horsepower	O
of	O
the	O
Color	B-Device
Computer	I-Device
...	O
we	O
believe	O
 [ it ] 	O
also	O
has	O
a	O
good	O
future	O
"	O
.	O
</s>
<s>
On	O
July	O
30	O
,	O
1986	O
,	O
Tandy	O
announced	O
the	O
Color	B-Device
Computer	I-Device
3	O
at	O
the	O
Waldorf-Astoria	O
Hotel	O
in	O
New	O
York	O
City	O
.	O
</s>
<s>
The	O
panel	O
behind	O
the	O
keyboard	O
and	O
cartridge	B-Protocol
door	O
plastic	O
were	O
changed	O
from	O
black	O
to	O
grey	O
.	O
</s>
<s>
The	O
CoCo	O
3	O
is	O
compatible	O
with	O
most	O
older	O
software	O
and	O
CoCo	B-Device
2	I-Device
peripherals	O
.	O
</s>
<s>
The	O
6809	B-Device
in	O
the	O
CoCo	O
1	O
and	O
2	O
runs	O
at	O
0.895MHz	O
.	O
</s>
<s>
The	O
CoCo	O
3	O
runs	O
at	O
that	O
frequency	O
by	O
default	O
,	O
but	O
is	O
software	O
controllable	O
to	O
run	O
at	O
twice	O
that	O
rate	O
;	O
OS-9	B-Operating_System
takes	O
advantage	O
of	O
that	O
capability	O
.	O
</s>
<s>
A	O
paged	B-General_Concept
memory	I-General_Concept
management	I-General_Concept
unit	I-General_Concept
breaks	O
up	O
the	O
6809	B-Device
's	O
64	O
KB	O
address	O
space	O
into	O
chunks	O
.	O
</s>
<s>
Omitted	O
from	O
the	O
GIME	O
are	O
the	O
seldom-used	O
SAM-created	O
Semigraphics	B-Data_Structure
8	O
,	O
12	O
,	O
and	O
24	O
modes	O
.	O
</s>
<s>
Previous	O
versions	O
of	O
the	O
CoCo	O
ROM	B-Device
were	O
licensed	O
from	O
Microsoft	O
,	O
but	O
Tandy	O
could	O
not	O
convince	O
them	O
to	O
provide	O
further	O
BASIC	O
updates	O
.	O
</s>
<s>
Instead	O
,	O
Microware	B-Operating_System
provided	O
extensions	O
to	O
Extended	B-Language
Color	I-Language
BASIC	I-Language
to	O
support	O
the	O
new	O
display	O
modes	O
.	O
</s>
<s>
To	O
not	O
violate	O
the	O
spirit	O
of	O
the	O
licensing	O
agreement	O
between	O
Microsoft	O
and	O
Tandy	O
,	O
Microsoft	O
's	O
unmodified	O
BASIC	O
is	O
loaded	O
in	O
the	O
CoCo	O
3	O
's	O
ROM	B-Device
.	O
</s>
<s>
Upon	O
startup	O
,	O
the	O
ROM	B-Device
is	O
copied	O
to	O
RAM	O
and	O
patched	O
by	O
Microware	B-Operating_System
's	O
code	O
.	O
</s>
<s>
Microware	B-Operating_System
also	O
provided	O
a	O
version	O
of	O
the	O
OS-9	B-Operating_System
Level	O
2	O
operating	O
system	O
shortly	O
after	O
launch	O
.	O
</s>
<s>
OS-9	B-Operating_System
uses	O
memory-mapping	O
(	O
so	O
each	O
process	O
has	O
its	O
own	O
memory	O
space	O
up	O
to	O
64K	O
)	O
,	O
windowed	O
display	O
,	O
and	O
a	O
more	O
extensive	O
development	O
environment	O
that	O
includes	O
a	O
copy	O
of	O
BASIC09	B-Language
.	O
</s>
<s>
C	B-Language
and	O
Pascal	B-Application
compilers	O
were	O
available	O
.	O
</s>
<s>
Members	O
of	O
the	O
CoCo	O
OS-9	B-Operating_System
community	O
enhanced	O
OS-9	B-Operating_System
Level	O
2	O
for	O
the	O
CoCo	O
3	O
at	O
Tandy	O
's	O
request	O
,	O
but	O
Tandy	O
stopped	O
production	O
of	O
the	O
CoCo	O
3	O
before	O
the	O
upgrade	O
was	O
officially	O
released	O
.	O
</s>
<s>
Most	O
of	O
the	O
improvements	O
made	O
it	O
into	O
NitrOS-9	O
,	O
a	O
major	O
rewrite	O
of	O
OS-9/6809	O
Level	O
2	O
for	O
the	O
CoCo	O
3	O
to	O
take	O
advantage	O
of	O
the	O
features	O
and	O
speed	O
of	O
the	O
Hitachi	B-General_Concept
6309	I-General_Concept
(	O
if	O
available	O
)	O
.	O
</s>
<s>
Internally	O
the	O
CoCo	O
1	O
and	O
CoCo	B-Device
2	I-Device
models	O
are	O
functionally	O
identical	O
.	O
</s>
<s>
Device	O
selection	O
based	O
on	O
MPU	O
memory	O
address	O
to	O
determine	O
if	O
the	O
MPU	O
access	O
is	O
to	O
DRAM	O
,	O
ROM	B-Device
,	O
PIA	O
,	O
etc	O
.	O
</s>
<s>
However	O
,	O
an	O
unusual	O
mode	O
available	O
by	O
the	O
SAM	O
is	O
called	O
the	O
Address	O
Dependent	O
mode	O
,	O
where	O
ROM	B-Device
reads	O
(	O
since	O
they	O
do	O
not	O
use	O
the	O
DRAM	O
)	O
occur	O
at	O
1.8MHz	O
but	O
regular	O
RAM	O
access	O
occurs	O
at	O
.89MHz	O
.	O
</s>
<s>
In	O
effect	O
,	O
since	O
the	O
BASIC	O
interpreter	O
runs	O
from	O
ROM	B-Device
,	O
putting	O
the	O
machine	O
in	O
this	O
mode	O
would	O
nearly	O
double	O
the	O
performance	O
of	O
a	O
BASIC	O
program	O
while	O
maintaining	O
video	O
display	O
and	O
DRAM	O
refresh	O
.	O
</s>
<s>
Despite	O
this	O
,	O
however	O
,	O
the	O
"	O
high	O
speed	O
POKE	B-Language
"	O
was	O
used	O
by	O
many	O
CoCo	O
BASIC	O
programs	O
even	O
though	O
it	O
overclocked	B-Application
the	O
hardware	O
in	O
the	O
CoCo	O
,	O
which	O
was	O
only	O
rated	O
for	O
1MHz	O
operation	O
.	O
</s>
<s>
Writing	O
even	O
bytes	B-Application
sets	O
that	O
register	O
bit	O
to	O
0	O
,	O
while	O
writing	O
odd	O
bytes	B-Application
sets	O
it	O
to	O
1	O
.	O
</s>
<s>
The	O
Motorola	B-General_Concept
6847	I-General_Concept
is	O
display	O
generator	O
capable	O
of	O
displaying	O
text	O
and	O
graphics	O
contained	O
within	O
a	O
roughly	O
square	O
display	O
matrix	O
256	O
pixels	O
wide	O
by	O
192	O
lines	O
high	O
.	O
</s>
<s>
This	O
display	O
mode	O
occupies	O
512	O
bytes	B-Application
of	O
memory	O
from	O
$	O
400-	O
$5FF	O
and	O
is	O
a	O
32	O
character	O
wide	O
screen	O
with	O
16	O
lines	O
.	O
</s>
<s>
The	O
ROM	B-Device
character	O
generator	O
only	O
holds	O
64	O
characters	O
,	O
so	O
no	O
lowercase	O
characters	O
are	O
provided	O
.	O
</s>
<s>
Semigraphics	B-Data_Structure
is	O
a	O
mode	O
where	O
alphanumerics	O
and	O
low	O
resolution	O
graphics	O
can	O
be	O
mixed	O
together	O
.	O
</s>
<s>
The	O
colorset	O
selection	O
does	O
not	O
affect	O
semigraphics	B-Data_Structure
characters	O
.	O
</s>
<s>
The	O
6847	O
is	O
capable	O
of	O
a	O
Semigraphics	B-Data_Structure
6	O
display	O
mode	O
,	O
where	O
two	O
bits	O
select	O
a	O
color	O
and	O
6	O
bits	O
determine	O
which	O
1/6	O
of	O
the	O
character	O
box	O
is	O
lit	O
.	O
</s>
<s>
Only	O
two	O
colors	O
are	O
available	O
in	O
graphics	O
blocks	O
when	O
using	O
Semigraphics	B-Data_Structure
6	O
on	O
the	O
CoCo	O
.	O
</s>
<s>
The	O
default	O
alphanumeric	O
display	O
for	O
the	O
CoCo	O
is	O
Semigraphics	B-Data_Structure
4	O
.	O
</s>
<s>
By	O
setting	O
the	O
SAM	O
such	O
that	O
it	O
believes	O
it	O
is	O
displaying	O
a	O
full	O
graphics	O
mode	O
,	O
but	O
leaving	O
the	O
VDG	O
in	O
Alphanumeric/Semigraphics	O
4	O
mode	O
,	O
it	O
is	O
possible	O
to	O
subdivide	O
the	O
character	O
box	O
into	O
smaller	O
pieces	O
.	O
</s>
<s>
This	O
creates	O
the	O
"	O
virtual	O
"	O
modes	O
Semigraphics	B-Data_Structure
8	O
,	O
12	O
,	O
and	O
24	O
.	O
</s>
<s>
In	O
these	O
modes	O
it	O
was	O
possible	O
to	O
mix	O
bits	O
and	O
pieces	O
of	O
different	O
text	O
characters	O
as	O
well	O
as	O
Semigraphics	B-Data_Structure
4	O
characters	O
.	O
</s>
<s>
These	O
modes	O
were	O
an	O
interesting	O
curiosity	O
but	O
not	O
widely	O
used	O
,	O
as	O
the	O
Semigraphics	B-Data_Structure
24-screen	O
consumed	O
6144	O
bytes	B-Application
of	O
memory	O
.	O
</s>
<s>
A	O
programmer	O
's	O
reference	O
manual	O
for	O
the	O
CoCo	O
states	O
that	O
due	O
to	O
a	O
fire	O
at	O
Tandy	O
's	O
research	O
lab	O
,	O
the	O
papers	O
relating	O
to	O
the	O
semigraphics	B-Data_Structure
modes	O
were	O
shuffled	O
,	O
and	O
so	O
some	O
of	O
the	O
semigraphics	B-Data_Structure
modes	O
were	O
never	O
documented	O
.	O
</s>
<s>
Resolution	O
graphics	O
store	O
8	O
pixels	O
per	O
byte	B-Application
and	O
are	O
available	O
in	O
128×64	O
,	O
128×96	O
,	O
128×192	O
,	O
and	O
256×192	O
modes	O
.	O
</s>
<s>
Color	O
graphics	O
have	O
4	O
pixels	O
per	O
byte	B-Application
and	O
are	O
available	O
in	O
64×64	O
,	O
128×64	O
,	O
128×96	O
,	O
and	O
128×192	O
.	O
</s>
<s>
On	O
PAL	B-Language
televisions	O
,	O
instead	O
of	O
solid	O
orange	O
and	O
blue	O
,	O
artifacts	O
appear	O
as	O
vertical	O
stripes	O
of	O
green	O
and	O
peach	O
with	O
soft	O
edges	O
and	O
a	O
width	O
of	O
almost	O
four	O
pixels	O
.	O
</s>
<s>
Most	O
Color	B-Device
Computer	I-Device
games	O
start	O
with	O
a	O
title	O
screen	O
and	O
ask	O
the	O
user	O
to	O
press	O
the	O
reset	O
button	O
until	O
the	O
colors	O
are	O
correct	O
.	O
</s>
<s>
This	O
is	O
fixed	O
on	O
the	O
Color	B-Device
Computer	I-Device
3	O
,	O
and	O
the	O
other	O
colorset	O
can	O
be	O
chosen	O
by	O
holding	O
F1	O
during	O
reset	O
.	O
</s>
<s>
Late	O
in	O
the	O
CoCo	B-Device
2	I-Device
production	O
run	O
,	O
the	O
enhanced	O
6847T1	O
VDG	O
was	O
used	O
.	O
</s>
<s>
The	O
lowercase	O
capability	O
is	O
disabled	O
by	O
default	O
on	O
these	O
CoCo	B-Device
2s	I-Device
,	O
and	O
is	O
not	O
mentioned	O
in	O
the	O
manual	O
.	O
</s>
<s>
Cassette	O
playback	O
or	O
an	O
analog	O
signal	O
can	O
be	O
also	O
be	O
routed	O
from	O
the	O
cartridge	B-Protocol
port	O
to	O
the	O
TV	O
speaker	O
.	O
</s>
<s>
There	O
are	O
two	O
Peripheral	B-General_Concept
Interface	I-General_Concept
Adapter	I-General_Concept
chips	O
in	O
all	O
CoCo	O
models	O
.	O
</s>
<s>
In	O
the	O
CoCo	O
3	O
,	O
a	O
new	O
VLSI	O
ASIC	O
called	O
(	O
officially	O
)	O
the	O
Advanced	O
Color	O
Video	B-General_Concept
Chip	I-General_Concept
(	O
ACVC	O
)	O
or	O
(	O
unofficially	O
)	O
the	O
Graphics	O
Interrupt	O
Memory	O
Enhancer	O
(	O
GIME	O
)	O
,	O
integrated	O
the	O
functions	O
of	O
the	O
SAM	O
and	O
VDG	O
while	O
enhancing	O
the	O
capabilities	O
of	O
both	O
.	O
</s>
<s>
The	O
processor	O
was	O
changed	O
to	O
the	O
68B09E	B-Device
and	O
the	O
PIA	O
was	O
changed	O
to	O
the	O
68B21	O
,	O
which	O
are	O
2MHz	O
parts	O
.	O
</s>
<s>
Wayne	O
Green	O
wrote	O
in	O
80	O
Micro	O
in	O
December	O
1982	O
that	O
Tandy	O
had	O
"	O
virtually	O
abandoned	O
"	O
the	O
Color	B-Device
Computer	I-Device
.	O
</s>
<s>
As	O
with	O
its	O
other	O
computers	O
,	O
Tandy	O
attempted	O
to	O
monopolize	O
hardware	O
and	O
software	O
sales	O
,	O
but	O
,	O
he	O
wrote	O
,	O
the	O
Color	B-Device
Computer	I-Device
was	O
incompatible	O
with	O
other	O
Tandy	O
software	O
and	O
what	O
was	O
available	O
was	O
of	O
poor	O
quality	O
.	O
</s>
<s>
Some	O
of	O
these	O
systems	O
run	O
OS9/68k	O
,	O
which	O
is	O
similar	O
to	O
OS-9	B-Operating_System
.	O
</s>
<s>
Frank	O
Hogg	O
Labs	O
introduced	O
the	O
Tomcat	O
TC-9	O
in	O
June	O
1990	O
,	O
which	O
is	O
somewhat	O
compatible	O
with	O
the	O
but	O
is	O
only	O
able	O
to	O
run	O
OS-9	B-Operating_System
software	O
.	O
</s>
<s>
A	O
later	O
version	O
called	O
the	O
TC-70	O
has	O
strong	O
compatibility	O
with	O
the	O
MM/1	O
,	O
and	O
also	O
runs	O
OS-9/68K	O
.	O
</s>
<s>
Multi-Media	O
One	O
was	O
introduced	O
in	O
July	O
1990	O
,	O
runs	O
OS-9/68K	O
on	O
a	O
15MHz	O
Signetics	O
68070	O
processor	O
with	O
and	O
a	O
640×208	O
graphics	O
resolution	O
as	O
well	O
as	O
supporting	O
a	O
640×416	O
interlaced	O
mode	O
.	O
</s>
<s>
It	O
includes	O
a	O
SCSI	B-Architecture
interface	O
,	O
stereo	O
A/D	O
and	O
D/A	O
conversion	O
,	O
an	O
optional	O
MIDI	O
interface	O
,	O
and	O
an	O
optional	O
board	O
to	O
upgrade	O
the	O
CPU	O
to	O
a	O
Motorola	B-Device
68340	I-Device
.	O
</s>
<s>
The	O
AT306	O
(	O
also	O
known	O
as	O
the	O
MM/1B	O
)	O
is	O
a	O
successor	O
to	O
the	O
MM/1	O
that	O
contains	O
a	O
Motorola	O
68306	O
CPU	O
,	O
OS-9/68K	O
3.0	O
,	O
and	O
allows	O
ISA	B-Architecture
bus	I-Architecture
cards	O
.	O
</s>
<s>
The	O
PT68K-4	O
has	O
the	O
footprint	O
of	O
an	O
IBM	O
PC	O
and	O
seven	O
8-bit	O
ISA	B-Architecture
slots	I-Architecture
.	O
</s>
<s>
It	O
contains	O
a	O
6809	B-Device
CPU	O
core	O
which	O
can	O
run	O
at	O
25MHz	O
.	O
</s>
<s>
The	O
Dragon	B-Device
32	I-Device
and	I-Device
64	I-Device
are	O
British	O
cousins	O
of	O
the	O
CoCo	O
based	O
on	O
a	O
reference	O
design	O
from	O
Motorola	O
that	O
was	O
produced	O
as	O
an	O
example	O
of	O
the	O
capabilities	O
of	O
the	O
MC6809E	O
CPU	O
when	O
coupled	O
with	O
the	O
MC6847	B-General_Concept
Video	B-General_Concept
Display	I-General_Concept
Generator	I-General_Concept
and	O
the	O
MC6883	O
Synchronous	O
Address	O
Multiplexer	O
.	O
</s>
<s>
The	O
BIOS	O
for	O
the	O
Dragon	B-Device
32	I-Device
was	O
written	O
based	O
on	O
specifications	O
and	O
API	O
drawn	O
up	O
by	O
Microsoft	O
and	O
,	O
to	O
a	O
certain	O
extent	O
,	O
PA	O
Consulting	O
of	O
Cambridge	O
.	O
</s>
<s>
The	O
Dragon	O
was	O
a	O
much	O
improved	O
unit	O
with	O
video	O
output	O
in	O
addition	O
to	O
the	O
TV	O
output	O
of	O
the	O
CoCo	O
and	O
CoCo	B-Device
2	I-Device
.	O
</s>
<s>
It	O
also	O
featured	O
a	O
Centronics	O
parallel	B-Device
port	I-Device
(	O
not	O
present	O
on	O
any	O
CoCo	O
)	O
,	O
an	O
integrated	O
6551A	O
serial	O
UART	O
(	O
on	O
the	O
Dragon	B-Device
64	I-Device
)	O
,	O
and	O
a	O
higher-quality	O
keyboard	O
.	O
</s>
<s>
In	O
Brazil	O
,	O
there	O
were	O
several	O
CoCo	O
clones	O
,	O
including	O
the	O
Prológica	B-Device
CP	I-Device
400	I-Device
Color	I-Device
and	O
CP	B-Device
400	I-Device
Color	O
II	O
,	O
the	O
Varix	O
VC	O
50	O
,	O
the	O
LZ	O
Color	O
64	O
,	O
the	O
Dynacom	O
MX-1600	O
,	O
the	O
Codimex	O
CD-6809	O
,	O
and	O
the	O
vaporware	B-Application
Microdigital	O
TKS800	O
.	O
</s>
<s>
In	O
Mexico	O
,	O
the	O
Micro-SEP	O
,	O
a	O
CoCo	B-Device
2	I-Device
clone	O
with	O
64	O
KB	O
of	O
memory	O
,	O
was	O
introduced	O
by	O
the	O
Secretary	O
of	O
Education	O
.	O
</s>
<s>
A	O
Taiwan-based	O
company	O
,	O
Sampo	O
,	O
also	O
made	O
a	O
CoCo	O
clone	O
,	O
the	O
Sampo	O
Color	B-Device
Computer	I-Device
.	O
</s>
<s>
It	O
is	O
believed	O
that	O
Tandy	O
blocked	O
sales	O
in	O
the	O
US	O
with	O
legal	O
action	O
due	O
to	O
copyright	O
infringements	O
on	O
the	O
ROM	B-Device
code	O
.	O
</s>
<s>
The	O
TRS-80	B-Device
MC-10	I-Device
,	O
or	O
Micro	O
Color	B-Device
Computer	I-Device
,	O
was	O
sold	O
in	O
Radio	O
Shack	O
stores	O
as	O
an	O
entry-level	O
computer	O
at	O
a	O
lower	O
cost	O
than	O
the	O
CoCo	O
.	O
</s>
<s>
Like	O
the	O
CoCo	O
,	O
it	O
uses	O
the	O
MC6847	B-General_Concept
VDG	O
and	O
Microsoft	B-Language
BASIC	I-Language
,	O
but	O
with	O
the	O
MC6803	O
instead	O
of	O
the	O
6809	B-Device
.	O
</s>
