Color Computer 2
Color Computer 2



Setname:  coco2   
Year: 1983
Manufacturer: Tandy Radio Shack
Status: good  works
Type: Home Computer
Parent: Color Computer
Emulation info
Overall emulation:  good   
Color emulation:  good  
Sound emulation:  good  
Graphics emulation:  good  
Savestates:  unsupported   

Tech info
 Base hardware: (available in all slot configurations)
M6809E ("maincpu")cpu 3579545 Hz
Speaker ("mono")audio
DAC ("dac")audio
Wave ("wave")audio
Screen ("screen")raster horizontal 320 x 240 @ 60.000000
Media devices
cassette ("cassette") cassette cass wav, cas
cartridge ("ext") cartridge cart ccc, rom
harddisk ("vhd0") harddisk1 hard1 vhd
harddisk ("vhd1") harddisk2 hard2 vhd
RAM options
4K 4096
16K 16384
32K 32768
64K 65536
Software lists

 Optional hardware: (available with specific slot configurations)

 Configure the slot options for coco2:
 Slot Value

Show detailed info about 'Configurations' of this system

Right Controller Port (P1) Unconnected
 The Rat Graphics Mouse
 Diecom Light Gun Adaptor
Left Controller Port (P2) Unconnected
 The Rat Graphics Mouse
 Diecom Light Gun Adaptor
Hi-Res Joystick Interfaces None
 Hi-Res in Right Port
 Hi-Res CoCoMax 3 Style in Right Port
 Hi-Res in Left Port
 Hi-Res CoCoMax 3 Style in Left Port
Cart Auto-Start Off
Real Time Clock Disto
Becker Port Off
Drivewire Server TCP Port 65500
RX Baud 110
Start Bits 0
Data Bits 5
Parity None
Stop Bits 0
Artifacting Off

Show detailed info about 'Slot Options' of this system
Slot options

NameValueCompatible device(s)
ext banked_16kcocopak_banked
 fdcv11 coco_fdc_v11
rs232 keyboardserial_keyboard
 printer serial_printer

Romset info
ROM NameSizeCRC32SHA1Dump StateBIOS option
bas12.rom8192 543688050f14dc46c647510eb0b7bd3f53e33da07907d04fgood
extbas11.rom8192 a82a6254ad927fb4f30746d820cb8b860ebb585e7f095deagood


* CPU: Motorola 6809E 0.895 MHz (or 1.79 MHz)
* RAM: 16k, 32k and 64k, depending on models
* ROM: 8k (Color Basic) but later models had 16k (Extended Color Basic)
* Text Modes: max : 16 x 32, min : 16 x 8
* Graphic Modes: Several graphic modes, max : 256 x 192 (with 2 colors)
* Colors: 9
* Sound: 1 voice (6-bit DAC)
* I/O Ports: Tape, RGB, Joystick (2), Monitor, Cartridge, Serial RS232
* Keyboard: Full-stroke 53-keys keyboard + Arrow keys, BREAK, CLEAR, SHIFT (x2)
* OS: OS-9 Level 1
* Built In Language: Tandy (Microsoft) BASIC interpreter


MESS emulates two variants of the Color Computer 2

* coco2 [Tandy Color Computer 2]
* coco2b [Tandy Color Computer 2B]

For both drivers, MESS supports the following devices

- a "cartridge" (cart), for .ccc and .rom files
- a "cassette" (cass), for tapes in .wav and .cas format
- up to four floppy drives, "floppydisk0" (flop0) to "floppydisk3" (flop3), for disk images in one of the following formats: .dsk, .os9, .vdk and .dmk

Also a "snapshot" (dump) feature is available for .pak files and a "quickload" (quik) feature is available for .bin files.

Finally, the "printer" (prin) is emulated as well.


MESS supports .cas files. Not all of these work; don't panic.

You can pick the cassette image you wish to run from the FILE MANAGER in the Tab/Options menu. Once you've selected the image, go back into the CoCo2 emulation, and use "scroll lock" to set it back in keyboard emulation mode.

If it's a BASIC program, type

If it's an assembler programs, type

If you include the name of the file (eg. CLOAD "PROG") it will skip any files preceding the one you specified.


MESS supports .pak files. Go to file menu pick the .pak. It should automatically start running the game. If it does not run, it isn't supported yet.


MESS supports .rom files. Go to file menu and pick the .rom. Reset to CoCo2 and it will start running the game. If it does not run it isn't supported yet.

Floppy Disks

MESS supports .dsk files. Basically the same as cassette images, except you insert the image in Floppy Disk#1 from the file manager. Once you return to the coco2 emulation, switch back to keyboard emulation mode by pressing SCROLL LOCK and type

To load a binary file (/BIN), type
(replacing the ":1" in LOADM with the appropriate drive designation ":0" through ":3" )

To load a basic file (/BAS), type

(Thanks to "Axe" for the command summary)


These systems require full keyboard emulation to work correctly. At startup, full keyboard emulation mode is enabled by default. Whilst in full keyboard emulation mode, some key associated functionality may be disabled (like the ESC key for EXIT). The keyboard emulation mode is toggled using the "Scroll Lock" key (by default).

Original Keyboard: QWERTY Full-stroke keyboard, 53-keys

1! 2" 3# 4$ 5% 6& 7' 8( 9) 0 :* -= BREAK

Up Q W E R T Y U I O P @ <- ->


SHIFT Z X C V B N M ,< .> /? SHIFT


RAM options

Different RAM configurations are possible for these systems in MESS. You can switch between them, changing the -ramsize parameter. At command line, you simply have to add ''-ramsize ram_value'', where //ram_value// can assume one of the following values

64k (default)

History and Trivia

The TRS 80 Color Computer 2 (coco2) replaced the Color Computer "Model 1" in 1983. It has the same characteristics than the Model 1 but has a better keyboard and a more integrated circuitry.

There were several models of the Coco2, some with only 8k ROM (Color Basic) called Standard Color Computer 2, and others with 16k ROM (Extended Color Basic) called the Extended Color Computer 2. Some later models differ also in RAM capacity (16k, 32k or 64k).
It was replaced with the TRS-80 Color Computer 3 in 1986.

Tandy Color BASIC versions

(info from Lee Veal): In reality, the 'dialects' of BASIC on all versions of the TRS-80 Color Computer 1s & 2s were written by Microsoft for Tandy. That includes Color BASIC (CB), Extended Color BASIC (ECB) and Disk Extended Color BASIC (DECB). In fact, with very few modifcations, BASIC programs from an IBM-PC or compatible using Microsoft BASIC could run on a CoCo and viceversa. (The way I know that is that I did it. Some were quite complex graphics oriented programs.) Within one-half K of the beginning the Color BASIC ROM address, there's a character string that reads "COLOR BASIC 1.0(C) 1980 TANDYMICROSOFT". When you fire up a CoCo 1 that has only the Color BASIC ROM, you'll see on the screen
(C) 1980 TANDY

The authors of Tandy's Color BASIC (Microsoft) left their name in the code, but they left it off the opening display. Subsequent levels of CoCo BASIC (Extended CB and Disk Extended CB) had Microsoft prominently displayed in the opening display. Thus, Color BASIC was quite compatible for obvious reasons with the BASIC that Microsoft develped for the PC. Extended and Disk Extended versions of CoCo BASIC were
even more compatible with Microsoft's BASIC for the PC.

On the other hand, the BASIC dialects contained in computers like the Commodore-64, TI-994A, etc were quite incompatible with any version of Microsoft BASIC.

The BASIC developed by Microware (the developers of the OS-9 operating system and originally Tandy's first choice of a BASIC developer), called BASIC09, was NOT compatible with Microsoft BASIC. BASIC09 is and was a powerful language that compiled to intermediate code but it is more akin to Pascal then BASIC.

== CoCo & CoCo 2 Double Speed ==

(info from Gary Clouse): The double speed mode was not really accomplished by changing the clock speed. The Synchronous address multiplexor (SAM) chip by default generated memory refresh cycles for the entire address space. The "double speed poke" disabled the refresh cycle for the upper 32k memory address, where the ROM was mapped. Since the ROM was static, it didn't need this and since BASIC spent most of its time in the rom routines, it would appear to nearly double the speed. The flip side of this was that many I/O functions that relied on timing loops would be unusable, such as saving data to a tape. Also if you were using the upper 32k of ram, the double speed poke would wipe the memory.

(info from


* CoCo Quest Color Computer Games and More! --
* Sock Master's Web Page --
* --
* Dragon & Tandy CoCo Resources --
* CoCo 2 at --

Other Emulators

* Color Computer II Emu by Jeff Vavasour --

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