TRS- 80 Color Computer
1977- Project “Green Thumb”
1980 VideoTex Unit
Motorola 6809E
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-8 bit with some 16 bit features
-2-8bit accumulators (A and B could be combined into a 16 bit register)
-2-16 bit Registers (X and Y)
-2-16-bit stack pointers.
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The index and stack registers allowed very advanced addressing modes. Program counter relative addressing allowed for
the easy creation of position-independent code, while a user stack pointer (U) facilitated the creation of reentrant code. The
6809 was the first microprocessor able to use fully position-independent code without the use of programming tricks.
The 6809 was source-compatible with the 6800, though the 6800 had 78 instructions to the 6809's 59. Some instructions
were replaced by more general ones which the assembler translated into equivalent operations and some were even
replaced by addressing modes. The instruction set and register complement were highly orthogonal, making the 6809 easier
to program than the 6800 or 6502.
Other features were one of the first hardware-implementations of a multiplication instruction in an MPU, full 16-bit arithmetic,
and an especially fast interrupt system. Like the 6800, it included an undocumented address bus test instruction with the
nickname Halt and Catch Fire (HCF)
The 6809's state machine and control logic, unlike many processors of the day, was mostly implemented using a large PLA
and asynchronous random logic (a trait of early designs and, partly, of RISC) rather than microcoded. The 6809 used the
two-phase clock cycle directly as the basic machine cycle.
Although this means fewer clock cycles per instruction compared to the Z80, for instance, the latter's higher resolution state
machine allowed clock frequencies 3-5 times as high without demanding faster memory chips, which was often the limiting
factor. This is because the Z80 combines two full (but short) clock cycles into a relatively long memory access period
compared to the clock, while the more asynchronous 6809 instead has relatively short memory access times: depending on
version and speed grade, approximately 60% of a single clock cycle was typically available for memory access in a 6809
(see data sheets).
The 6809 had an internal two-phase clock generator (needing only an external crystal) whereas the 6809E needed an
external clock generator. There were also variants such as the 68A09(E) and 68B09(E); the internal letter indicates the
processor's rated clock speed.
S.A.M
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The SAM is a multifunction device that performs the following functions:
Clock generation and synchronization for the 6809E MPU and 6847 VDG
Up to 64K Dynamic Random Access Memory (DRAM) control and refresh
Device selection based on MPU memory address to determine if the MPU access is to DRAM, ROM, PIA, etc.
Duplication of the VDG address counter to "feed" the VDG the data it is expecting
The SAM was designed to replace numerous small LS/TTL chips into one integrated package. Its main purpose is to control the DRAM
but, as outlined above, it integrates several other functions as well. It is connected to a crystal at 4 times the television colorburst
frequency (14.31818 MHz for NTSC countries). This is divided by 4 internally and is fed to the VDG for its own internal timing
(3.579545 MHz for NTSC). The SAM also divides the master clock by 16 (or 8 in certain cases) for the two phase MPU clock; in NTSC
this is .89 MHz (or 1.8 MHz if divided by 8).
Switching the SAM into 1.8 MHz operation gives the CPU the time ordinarily used by the VDG and refresh. As such, the display shows
garbage; this mode was seldom used. However, an unusual mode available by the SAM is called the Address Dependent mode, where
ROM reads (since they do not use the DRAM) occur at 1.8 MHz but regular RAM access occurs at .89 MHz. In effect, since the BASIC
interpreter runs from ROM, putting the machine in this mode would nearly double the performance of a BASIC program while maintaining
video display and DRAM refresh. Of course, this would throw off the software timing loops and I/O operations would be affected. Despite
this, however, the "high speed POKE" was used by many CoCo BASIC programs even though it overclocked the hardware in the CoCo,
which was only rated for 1 MHz operation.
The SAM has no connection to the MPU data bus. As such, it is programmed in a curious manner; its 16-bit configuration register is
spread across 32 memory addresses (FFC0-FFDF). Writing even bytes sets that register bit to 0, Writing to odd bytes sets it to 1.
Due to limitations in 40-pin packaging, the SAM contains a duplicate of the VDG's internal 12-bit address counter. Normally this counter's
settings are set to duplicate the VDG's display mode. However, this is not required and results in the creation of some new display modes
not possible when the VDG is used in a system alone. Instead of the VDG requesting data from RAM by itself, the VDG is "fed" data by
the SAM's internal copy of the VDG address counter. This process is called "Interleaved Direct Memory Access" (IDMA) by Motorola and
ensures that the processor and VDG always have full access to this shared memory resource with no wait states or contention.
There are two versions of the SAM. The early one is labeled MC6883 and/or SN74LS783; the later version is labeled SN74LS785. There
are some minor timing differences, but the major difference is the support of an 8-bit refresh counter in the 785 version. This allowed for
use of inexpensive 16K by 4-bit and certain 64K by 1-bit DRAMs. Some third party bank-switching memory upgrades that used 256K
DRAMs needed this 8-bit refresh counter to work.
VDG
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The MC6847 is a relatively simple display generator compared to the display chips of some of the CoCo's 8-bit
rivals. It is capable of displaying text and graphics contained within a roughly square display matrix 256 pixels wide
by 192 lines high. It is capable of displaying 9 colors: black, green, yellow, blue, red, buff (almost-but-not-quite
white), cyan, magenta, and orange. The low display resolution is a necessity of using television sets as display
monitors. Making the display wider risked cutting off characters due to overscan. Compressing more dots into the
display window would easily exceed the resolution of the television and be useless, as the periphery of a textual
screen would be unreadable.
Alphanumeric/Semigraphics display
Sample character set display of 6847 VDG
The CoCo is physically wired such that its default alphanumeric display is actually "Semigraphics 4" mode.
In alphanumeric mode, each character is a 5 dot wide by 7 dot high character in a box 8 dots wide and 12 lines
high. This display mode consumes 512 bytes of memory and is a 32 character wide screen with 16 lines. The
internal ROM character generator only holds 64 characters, so no lower case characters are provided. Lower case
characters were rendered as upper case characters with inverted color. Although simulated screen shots would
show this as green on black, on most CoCo generations it was actually green on very dark green.
Semigraphics is a hybrid display mode where alphanumerics and chunky block graphics can be mixed together on
the same screen. If the 8th bit of the character is set, it is a semigraphics character. If cleared, it is an
alphanumeric. When the 8th bit is set, the next three bits determine the color and last 4 bits determine which
"quadrant" of the character box is either the selected color or black. This is the only mode where it is possible
(without sneaky tricks) to display all 9 colors on the screen simultaneously. If used to only display semigraphics,
the screen becomes a 64x32 9 color graphics mode. The CoCo features several BASIC commands to manage
this screen as a low-res graphics display.
The alphanumeric display has two colorsets. The one used by default on the CoCo has black characters on a
green background. The alternate has black characters on an orange background. The colorset selection does not
affect semigraphics characters. The border in this mode is always black.
A programmer's reference manual for the CoCo states that due to a fire at Tandy's research lab, the papers
relating to the semigraphics modes were shuffled, and so some of the semigraphics modes were never
documented. CoCo enthusiasts created experimental programs to try to reverse engineer the modes, and were
able to reconstruct the missing documentation.
VDG
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The 6847 is capable of a Semigraphics 6 display mode, where two bits select a color and 6 bits determine which
1/6 of the character box is lit. In this mode only 4 colors are possible but the Colorset bit of the VDG can select two
different groups of the 4 colors. Due to a peculiarity of its hardware, only two colors are available in graphics
blocks when using Semigraphics 6 on the CoCo.
Additional Semigraphics modes
By setting the SAM such that it believes it is displaying a full graphics mode, but leaving the VDG in
Alphanumeric/Semigraphics 4 mode, it is possible to subdivide the character box into smaller pieces. This creates
the "virtual" modes Semigraphics 8, 12, and 24.In these modes it was possible to mix bits and pieces of different
text characters as well as Semigraphics 4 characters. These modes were an interesting curiosity but not widely
used, as the Semigraphics 24-screen consumed 6144 bytes of memory. These modes were not implemented on
the CoCo 3.
Graphics display
There were several full graphics display modes, which were divided into two categories: "resolution" graphics and
"color" graphics. In resolution modes, each pixel is addressable as either on or off. There are two colorsets
available, the first was black dots on a green background and green border, the second, more commonly used one
has white dots on a black background with a white border. In color modes, each pixel was two bits, selecting one
of four colors. Again the colorset input to the VDG determined which colors were used. The first colorset has a
green border, and the colors green, yellow, red, and blue were available. The second colorset has a white border
and the colors white, cyan, magenta and orange were available. Resolution graphics have 8 pixels per byte and
are available in 128x64, 128x96, 128x192, and 256x192 densities. Color graphics have 4 pixels per byte and are
available in 64x64, 128x64, 128x96, and 128x192 densities. The maximum size of a graphics screen is 6144
bytes.
VDG
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Artifact colors
The 256x192 two color graphics mode uses four colors due to a quirk in the NTSC television system. It is not
possible to reliably display 256 dots across the screen due to the limitations of the NTSC signal and the phase
relationship between the VDG clock and colorburst frequency. In the first colorset, where green and black dots are
available, alternating columns of green and black are not distinct and appear as a muddy green color. However,
when one switches to the white and black colorset, instead of a muddy gray as expected, the result is either
orange or blue. Reversing the order of the alternating dots will give the opposite color. In effect this mode becomes
a 128x192 4 color graphics mode where black, orange, blue, and white are available (the Apple II created color
graphics by exploiting a similar effect). Most CoCo games used this mode as the colors available are more useful
than the ones provided in the hardware 4 color modes. Unfortunately the VDG internally can power up on either
the rising or falling edge of the clock, so the bit patterns that represent orange and blue are not predictable. Most
CoCo games would start up with a title screen and invited the user to press the reset button until the colors were
correct. The CoCo 3 fixed the clock-edge problem so it was always the same; a user would hold the F1 key during
reset to choose the other color set. On a CoCo 3 with an analog RGB monitor, the black and white dot patterns do
not artifact; to see them one would have to use a TV or composite monitor, or patch the games to use the
hardware 128x192 four color mode in which the GIME chip allows the color choices to be mapped. Users in PAL
countries saw green and purple stripes instead of solid red and blue colors.
Readers of The Rainbow or Hot CoCo magazine learned that they could use some POKE commands to switch the
6847 VDG into one of the artifact modes, while Extended Color Basic continued to operate as though it were still
displaying one of the 128x192 four-color modes. Thus, the entire set of Extended Color Basic graphics commands
could be used with the artifact colors. Some users went on to develop a set of 16 artifact colors using a 4x2 pixel
matrix, giving this set of colors: black, dark cyan, brick red, light violet, dark blue, azure (the blue above), olive
green, brown, purple, light blue, orange, yellow, light gray, blue-white, flesh, and white. Use of POKE commands
also made these colors available to the graphics commands, although the colors had to be drawn one horizontal
line at a time. Some interesting artworks were produced from these effects, especially since the CoCo Max art
package provided them in its palette of colors.
VDG
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Lower case and the 6847T1
Sample character set display of 6847T1 VDG in true lower case mode
The 6847 is capable of using an external character generator. Several third party add-on adapter boards would
allow the CoCo to display real lowercase characters.
Very late in the CoCo 2 production run, an enhanced VDG was available. Called the 6847T1, it included a lower
case character generator and the ability to display a green/orange or black border on the text screen. Its other
changes were mainly to reduce parts count by incorporating an internal data latch. The lower case capability of
this VDG is not enabled by default on this system and is not even mentioned in the manual. Only through some
tinkering and research was this feature discovered by intrepid CoCo users.
The 6847T1 may also carry the part number XC80652P; these may have been pre-release parts.
1980-1982 TRS 80 Color Computer
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-4k at launch
Later upgrades include 16K, 32K, and 64K
Microsoft Basic and later “Extended” Basic
Initial versions of the CoCo were upgraded to 32K by means of piggybacking two banks of 16K
memory chips and adding a few jumper wires. A later motherboard revision removed the 4K RAM
option and were upgraded to 32K with "half-bad" 64K memory chips as a cost-cutting measure.
These boards have jumpers marked HIGH/LOW to determine which half of the memory chip was
good. This was transparent to the BASIC programmer since in either configuration 32K of memory
was available. As memory production yields improved and costs went down, many (perhaps most)
32K CoCo 1s were shipped with perfectly good 64K memory chips; many utilities and programs
began to take advantage of the "hidden" 32K.
Eventually the 32K memory option was dropped entirely and only 16K or 64K versions were
offered. All versions that shipped with standard Color BASIC could be upgraded to Extended
BASIC by simply plugging a ROM into an empty socket provided on the motherboard.
TDP -100
• Toward the end of the CoCo 1 production run, a version of the
"CoCo" with a white case, called the TDP-100, was marketed
through Tandy Data Products (TDP) and sold through a different
distribution channel. Except for the nameplate and case, the TDP100 was identical to the CoCo 1.
• At some point after this, both the Coco and the TDP-100 shipped
with a white case which had ventilation slots that ran the entire
length of the case, rather than only on the sides. This ventilation
scheme was carried over to the CoCo 2.
• Some late versions of the CoCo also shipped with a modified
keyboard, often referred to as the "melted" keyboard, which had
bigger keycaps but a similar rubbery feel.
• A number of peripherals were available: tape cassette storage, serial
printers, a 5.25 inch floppy disk drive, a pen and graphics tablet
called the "X-Pad", speech and sound generators, and joysticks.
1983-1986 Color Computer 2
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During the CoCo 1 production run, much of the discrete support circuitry had been re-engineered into a
handful of custom integrated circuits, leaving much of the circuit board area of the CoCo 1 as empty
space. To cut production costs, the case was shortened by about 25% and a new, smaller power supply
and motherboard were designed. The "melted" keyboard from the white CoCo 1 and the TDP-100 style
ventilation slots were carried over. Aside from the new look and the deletion of the 12 volt power supply
to the expansion connector, the computer was essentially 100% compatible with the previous generation.
The deletion of the 12 volt power supply crippled some peripherals such as the original floppy disk
controller, which then needed to be upgraded, installed in a Multi-Pak interface, or supplied with external
power.
Production was also partially moved to Korea during the CoCo 2's life-span, and many owners of the
Korean-built systems referred to them as "KoKos". Production in the USA and Korea happened in parallel
using the same part numbers; very few, if any, differences exist between the USA built and Korean built
CoCo 2 machines.
Upgraded BASIC ROMs were also produced, adding a few minor features and correcting some bugs. A
redesigned 5-volt disk controller was introduced with its own new Disk BASIC ROM (v1.1). This controller
added the "DOS" command which was used to boot the OS-9 operating system by Microware.
Later in the production run, the "melted" keyboard was replaced with a new, full-travel, typewriter-style
keyboard.
The final significant change in the life of the CoCo 2 was made for the models 26-3134B, 26-3136B, and
26-3127B (16 kB standard, 16 kB extended, and 64 kB extended respectively). Internally this model was
redesigned to use the enhanced VDG, the MC6847T1. This enhanced VDG allowed the use of lower
case characters and the ability to change the text screen border color. For compatibility reasons neither
of these features were used and were not enabled in BASIC, however the resourceful user could enable
them by setting certain memory registers. Midway during the production run of these final CoCo 2s, the
nameplate was changed from "Radio Shack TRS-80 Color Computer 2" to "Tandy Color Computer 2".
The red, green, and blue shapes were replaced with red, green, and blue parallelograms.
1986-1991 Color Computer 3
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On July 30, 1986, Tandy announced the Color Computer 3 at the Waldorf-Astoria Hotel in New York City.
It came with 128 kB of RAM, which could be upgraded to 512 kB. The keyboard surround and cartridge
door plastic were changed from black to grey. The keyboard layout was revised, putting the arrow keys in
a diamond configuration and adding CTRL, ALT, F1 and F2 keys. It sold in Radio Shack stores and Tandy
Computer Centers for $219.95.
The CoCo 3 was compatible with most of the CoCo 2's peripherals. Most older software ran on it. Taking
the place of the graphics and memory hardware in the CoCo 1 and 2 was an application-specific
integrated circuit (ASIC) called the "GIME" (Graphics Interrupt Memory Enhancement) chip. The GIME
also provided additional features:
Output to a composite video monitor or analog RGB monitor, in addition to the CoCo 1 and 2's TV output.
This did much to improve the clarity of its output.
A paged memory management unit which broke up the 6809's 64 kB address space into 8 x 8 kB
chunks. Although these chunks were considered to be too large by many programmers, the scheme
would later allow third party RAM upgrades of up to 2 MB (256 x 8 kB).
Text display with real lowercase at 32, 40, 64, or 80 characters per line and between 16 and 24 lines per
screen.
Text character attributes, including 8 foreground and 8 background colors, underline, and blink.
New graphics resolutions of 160, 256, 320 or 640 pixels wide by 192 to 225 lines.
Up to 16 simultaneous colors out of a palette of 64 displayable at one time (unless programming tricks
were employed to display more).
Omitted from the GIME were the seldom-used SAM-created Semigraphics 8, 12, and 24 modes. A
rumored 256 color mode (detailed in the original Tandy spec for the GIME) has never been found.
CoCo 3 , Microsoft and OS-9 etc
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Previous versions of the CoCo ROM had been licensed from Microsoft, but by this time Microsoft was not interested in extending the code
further. Instead, Microware provided extensions to Extended Color BASIC to support the new display modes. In order to not violate the
spirit of the licensing agreement between Microsoft and Tandy, Microsoft's unmodified BASIC software was loaded in the CoCo 3's ROM.
Upon startup, the ROM is copied to RAM and then patched by Microware's code. Although this was a clever way of adding features to
BASIC, it was not without some flaws: the patched code had several bugs, and support for many of the new hardware features was
incomplete.
Microware also provided a version of the OS-9 Level 2 operating system shortly after launch. This OS featured memory-mapping (so each
process had its own memory space up to 64K), windowed display, and a more extensive development environment that included a
bundled copy of BASIC09. C and Pascal compilers were available. Various members of the CoCo OS-9 community enhanced OS-9 Level
2 for the CoCo 3 at Tandy's request, but Tandy stopped production of the CoCo 3 before the upgrade was officially released. Most of the
improvements made it into NitrOS-9, a major rewrite of OS-9/6809 Level 2 for the CoCo 3 to take advantage of the added features and
speed of the Hitachi 6309 (if the unit has the Hitachi CPU installed).
Typical CoCo 3 system
The 6809 in the CoCo 1 and 2 ran at 0.895 MHz; the CoCo 3 runs at that frequency by default, but is software controllable to run at twice
that rate; OS-9 takes advantage of that capability. Some models of CoCo 1 and 2 were also capable of running at this higher speed, but
this was not supported or guaranteed.
A popular accessory was a high-resolution joystick adapter designed by CoCo enthusiast Steve Bjork. While it did increase the resolution
of the joystick/mouse interface by a factor of ten, it did so at the expense of CPU time. A modified version of this interface was included
with a software package by Colorware called CoCo-Max 3, by Dave Stamp. This was a MacPaint work-alike but added support for color
graphics. This was a very desirable product for CoCo owners and combined with a MacWrite-like word processor called MAX-10 (also by
Dave Stamp and internally named "MaxWrite"), provided much of the functionality of an Apple Macintosh, but with color graphics and at a
fraction of the cost.
While the CoCo 3 featured many enhancements and was well received, it was not without problems and disappointments. As initially
conceived, the CoCo 3 had much hardware acceleration and enhanced sound. However, internal politics crippled the design so it would
not be perceived as a threat to the Tandy 1000.
T his again limited the platform's potential as a game console. Early versions of the GIME had DRAM timing issues which caused random
freezes. Due to bugs in the GIME some features that were problematic were marked as "reserved" or "do not use" in the programming
and service manuals.
The power supply was marginal, and some would overheat if the system memory was expanded to the full 512 kB capacity due to the
considerable heat generated by the additional static RAM on the optional daughterboard.
Typical CoCo 3 Setup
Competition
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The CoCo's main competition was from the Commodore VIC-20, Commodore 64, Apple II, and the Atari 400 and Atari 800.
While the CoCo sported perhaps the most advanced 8-bit processor ever made, that processing power came at a significant price
premium. In order to sell the CoCo at a competitive price, its relatively expensive processor was not tied to any specialized video or sound
hardware. In comparison, the 6502-derived processor in the Commodore, Apple and Atari systems was much less expensive. Both
Commodore and Atari had invested in advanced graphics and sound chip design for arcade games and home gaming consoles. By tying
these specialized circuits with an inexpensive processor, Atari and Commodore systems were able to play sophisticated games with high
quality graphics and sound. The trade-off is between a system with an expensive CPU that does a lot of work, or an inexpensive CPU that
controls the registers of its sound and video hardware.
The CoCo video hardware was derived from a chip designed as display for a character based terminal, and is a completely "dumb"
device. Similarly, the sound hardware is little more than a 6-bit DAC under software control. All graphics and sound require direct CPU
intervention, and while this allows for great flexibility, its performance is much lower than dedicated hardware.
Games drove system sales then as they do now, and with its poor gaming performance, the CoCo attracted little interest in officially
licensed ports of popular games. The CoCo 3 did improve graphics capability and doubled CPU performance, but still contained no
hardware graphics or sound acceleration. Drawing was performed by the CPU, and most of the new graphics modes required at least
twice as much processor time due to increased display resolution and color depth. The sound hardware was not changed at all.
Every computer platform is a compromise, and despite the significant graphics and sound handicap the CoCo may have had, it still had a
sophisticated CPU under its hood with extremely high performance. There were many independent clones of popular games available,
but far more important was the availability of "killer apps" for the CoCo. For instance, CoCo-Max and Max-10 were clones of MacPaint
and MacWrite. The OS-9 operating system, a UNIX-like multi-tasking multi-user environment, was also available. Even the BASIC
interpreter was one of the most powerful available, and provided the user with a rich set of easy-to-use commands for manipulating onscreen graphics and playing sounds.
Some of the hardware limitations were overcome with external add-ons, particularly expansion cartridges. Some were made by Tandy,
some by other manufacturers. Examples are:
RS232 Program Pak, which provided a real RS232 UART for serial communications (the 6551A)
The Speech & Sound Pak, which provided a speech synthesizer and a sound generator chip
Word-Pak and Word-Pak II 80 column display adapters produced by PBJ, Inc. allowed connection to an external monochrome monitor
(not needed for CoCo 3).
300 baud modem pak
Advanced floppy and hard drive controllers (mostly for OS-9)
Key to taking advantage of these expansion capabilities is the Multi-Pak interface, which permits up to four devices such as these to be
attached to the system at the same time.
Send in the Clones
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Because the Color Computer is basically an “off the shelf” licensed Reference design by Motorolla, a number of Clones were made:
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The Dragon 32 and 64 computers were British cousins of the CoCo based on a reference design from Motorola that was produced as an
exemplar of the capabilities of the MC6809E (MPU) when coupled with the MC6847 (Video Display Generator - VDG) and the MC6883
(Synchronous Address Multiplexer - SAM). The BIOS code for the Dragon 32 was rewritten based on specifications and API drawn up by
Microsoft and, to a certain extent, PA Consulting of Cambridge. The Dragon was a much improved unit with video output in addition to the
TV output of the CoCo and CoCo 2. It also featured a Centronics parallel port (not present on any CoCo), an integrated 6551A serial
UART (on the Dragon 64), and a higher-quality keyboard. In 1983, a version of the Dragon was licensed for manufacture for the North
American market by Tano Corporation of New Orleans, Louisiana. Tano started production at their 48,000-square-foot (4,500 m2) facility
in September 83 and were running at capacity just one month later. Unfortunately sales weren't as good as expected and Tano stopped
production and support just one year later. A California surplus equipment company, California Digital, bought the remaining stock of
Tano built Dragon 64 shortly after and has had new in-the-box Dragon 64s available for purchase as of December 2009.
In Brazil, there existed several CoCo-clones, including the Prologica CP400 Color and CP400 Color II, the Varixx VC50, the LZ Color64,
the Dynacom MX1600, the Codimex CD6809 and the "vaporware" Microdigital TKS800.
In Mexico, the Micro-SEP, a CoCo 2 clone with 64 kB of memory, was introduced by the Secretary of Education. The Micro-SEP was
intended to be distributed nationally to all the public schools teaching the 7th to 9th grades. They were presented as a design of the
Center of Advanced Research and Studies (CINVESTAV) of the National Polytechnic Institute (IPN).]Like the Dragon, these computers
also included video output. Whether these computers were "designed" by this institute, or were licensed from the original design, is
unclear.
A Taiwan-based company, Sampo, also made a CoCo clone, the Sampo Color Computer.The Sampo was supposedly available in
Taiwan, Korea, and possibly other Asian countries. It is believed that Tandy blocked sales in the US with legal action due to copyright
infringements on the ROM code.
A cousin of the CoCo, The MC-10, or Micro Color Computer, was sold in Radio Shack stores as a lower cost, more entry-level computer
than the CoCo. Released in 1983, it was similar in appearance to the Timex Sinclair. It also used the MC6847 VDG and Microsoft Basic,
but featured the MC6803 instead of the 6809. It was just as bare-bones as the little Timex Sinclair model as well, lacking such things as
an 80 column printer and disk storage system, as well as a "real" keyboard. Accordingly, it did not sell well and was withdrawn after just
two years of production. An MC-10 clone, the Sysdata Tcolor, was available in Brazil with 16 kB ROM.
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Today..
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Today , there is still a dedicated an loyal user base. A US based company Called “Cloud 9 Tech” is still making
hardware “Upgrades” for the CoCo 3.
An open source implementation of OS9 called NitrOS9 is constantly being updated and maintained.
In 2001, RadiSys purchased Microware to acquire the Intel IXP-1200 network processor resources. This
acquisition infused Microware with capital and allowed Microware to continue OS-9 development and support.
On February 21, 2013, Microware LP (a partnership formed by Freestation of Japan, Microsys Electronics of
Germany and RTSI LLC of the USA) announced that they signed an Asset Purchase Agreement to buy the rights
to the names Microware, OS-9 and all assets from RadiSys.
RadiSys gave it’s blessing to the CoCo Users and NirOS9, but As of today, Mircroware LP, has not commented,
approved or done anything to the NitrOS9 project, so until an “official” word comes down, all development has
been put on hold.
CoCo fests are still being held every year at the end of April in Chicago. They always call it the “LAST” one, but
record crowds still keep it a feasible event for the Glenside Computer Club (hosts).
Lately, all Commodore Collecting has prices for any hardware gone “through the roof”, the CoCo is still cheap
enough of a hobby to get into without costing and arm and a leg.