====== Tandy TRS-80 Color Computer 3 (1986) ======
===== Features =====
* CPU: Motorola 68b09e (uses an external clock generator) 2 MHz (0.89MHz under RS-DOS for compatability 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
===== Usage =====
Read the entry for the Color Computer and Color Computer 2 drivers. Much of the information there also applies to this driver.
===== Known Issues =====
Besides fully emulating the Color Computer 3 this driver also contains some extras.
It contains an implementation of Jeff Vavasours' Virtual Hard Disk. See his Color Computer 3 emulator for information regarding it.
This driver also contains two different real time clocks. Currently they can be set under the "DIP switches". The two types are Disto and Cloud-9.
== 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
===== 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)//
===== Links =====
* 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
===== Other Emulators =====
* CoCo III Emu by Jeff Vavasour -- http://www.vavasour.ca/jeff/trs80.html#coco3
Generated on Sun Jul 19 10:17:28 2009