* CPU: Motorola 68b09e (uses an external clock generator) 2 MHz (0.89MHz under RS-DOS for compatibility with FD expansion unit)
* RAM: 128 KB (up to 512 KB. There were 1MB and 2MB upgrade boards as well)
* ROM: 32 KB
* Text Modes: 32 x 16, 40 x 25, 80 x 25
* Graphic Modes: Several graphic modes, the most interesting were: 320 x 200 (16 col.), 640 x 200 (4 col.), 640 x 400 (4 col. if 512 KB RAM)
* Colors: 64
* I/O Ports: Tape, Composite Video, analog RGB connector for use with Tandy CM-8 monitor, 2 joystick ports, cartridge slot, RS232
* Keyboard: Full-stroke keyboard
* OS: with optional disk drive : RS-DOS, OS-9 Level 2 was also popular
* Built In Language: Tandy Extended Color Basic
MESS supports three different systems
* coco3 [Tandy Radio Shack Color Computer 3 (NTSC)]
* coco3p [Tandy Radio Shack Color Computer 3 (PAL)]
* coco3h [Tandy Radio Shack Color Computer 3 (NTSC; HD6309)] - the MPU has been replaced by a Hitachi 6309, notice that this chip has extra features not documented by Hitachi
For each driver, MESS supports the following devices
- a "cartridge" (cart), for .ccc and .rom files
- a "cassette" (cass), for tapes in .wav and .cas format
- a "harddisk" (hd), for .vhd files
- 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. Real Time Clock
MESS contains two different real time clocks: Disto and Cloud-9. Currently they can be set under the "DIP Switches".
* Disto Real Time Clock
* Chip: OKI m6242B
* Addressed: $FF50 and $FF51
* Cloud-9 Real Time Clock
* Chip: Dallas Semiconductor's Phantom Time Chip DS1315
* Addressed: $FF79, $FF78, $FF7C Misc
Read the entry for the Color Computer and Color Computer 2 drivers. Much of the information there also applies to this driver.
MESS emulation also contains an implementation of Jeff Vavasours' Virtual Hard Disk. See his Color Computer 3 emulator for information regarding it. Keyboard
These systems require full keyboard emulation to work correctly. At startup, full keyboard emulation mode is enabled by default. Whilst in full keyboard emulation mode, some key associated functionality may be disabled (like the ESC key for EXIT). The keyboard emulation mode is toggled using the "Scroll Lock" key (by default).
Original Keyboard: QWERTY Full-stroke keyboard,
1! 2" 3# 4$ 5% 6& 7' 8( 9) 0 :* -= BREAK
ALT Q W E R T Y U I O P @ CLEAR Up
CTRL A S D F G H J K L ;+ ENTER Left Right
SHIFT Z X C V B N M ,< .> /? SHIFT Down
SPACEBAR F1 F2 RAM options
Different RAM configurations are possible for these drivers 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
History and Trivia
The Tandy Color Computer 3 is the successor of the Tandy/TRS-80 Color Computer 2.
The CoCo3 came with 128K RAM, an analog RGB video port, enhanced 640x192 graphics capability, a 64-color palette and much more. (All ports contained on the CoCo 1 and 2 models were also available on the CoCo3, e.g. RS-232 serial, cassette, right and left joystick and a 40-pin expansion slot.)
The CoCo3 was upgradeable to 512 KB RAM. (After-market RAM upgrades have gone as high as 8MB, with rumors that 16MB and 32MB RAM upgrades may also be possible). A Multi-Pak (a 4-port bus expander) plugged into the Expansion Slot allowed use of controllers for floppy disk drives, hard drives (MFM, RLL, SCSI and now even IDE), multi-port true RS-232 devices, MIDI units and much much more.
It can work with OS-9 Level II (an operating system designed for 6809 processors).
As its microprocessor was still an 8 bit (strange choice when Atari and Commodore were using a 68000), it couldn't access simultaneously to the 128k (or 512k), and thus used several RAM banks which could be switched (as the Thomson TO8, or MSX 2 computers). Unlike the CoCo and CoCo II the 3 had an interrupt controller. This did away with a lot of the timing loops used in its predecessors, and actually took some of the fun out of programming in Machine Language.
Tandy made several prototypes of a Color Computer model IV but it was never released.
(info from old-computers.com)
* CoCo Quest Color Computer Games and More! -- http://www.prowler-pro.com/coco/
* Sock Master's Web Page -- http://www.axess.com/twilight/sock/
* www.coco3.com -- http://www.coco3.com/
* CoCo 3 at old-computers.com -- http://old-computers.com/museum/computer.asp?c=109
* CoCo III Emu by Jeff Vavasour -- http://www.vavasour.ca/jeff/trs80.html#coco3