NAME  

Color Computer 3

MANUFACTURER  

Tandy Radio Shack

TYPE  

Home Computer

ORIGIN  

U.S.A.

YEAR  

1986

KEYBOARD  

Full-stroke keyboard, 53 keys.

CPU  

Motorola 68B09E

SPEED  

1.79 MHz

RAM  

128 KB upgradable to 512 KB

ROM  

32 KB

TEXT MODES 

32x16, 40x25, 80x25

GRAPHIC MODES 

Several graphic modes, the most interesting were: 320x200 (16 col.), 640x200 (4 col.),
640x400 (4 col. if 512 KB RAM)

COLORS  

64

SOUND  

1 voice (6-bit DAC)

SIZE / WEIGHT 

9 x 35 x 37,5 cm

I/O PORTS 

Tape, Composite Video, analog RGB connector for use with Tandy CM-8 monitor, 2 joystick ports, cartridge slot, RS232

OS  

RS-DOS, OS-9 Level 2 with disk-drives

POWER SUPPLY 

PSU built-in

PRICE  

$219.95 (USA, 1986)

 

Tandy Color Computer 3

Color Computer 3

 The "TANDY Color Computer 3" followed the 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 built-in Language, named Disk Extended Color Basic 2.1, was a Microsoft BASIC with enhancements by Microware. It was similar to that of the CoCo 2, but Microware added the commands/functions to take advantage of the higher resolution graphics and text.

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.

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 2 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.