Tandyy TRS-80 Color Computer (1980)
YOU’LL NEED THIS
A COPY OF VCC
Downloads are provided on the project’s GitHub page. Extra system ROMs not required. https://github.com/VCCE/VCC/releases
THIS MONTH we explore a true American classic: the TRS-80 Color Computer, otherwise known as “CoCo” for short. Not to be confused with the original TRS-80 manufactured in the late 1970s, the CoCo was to be a new system for the 1980s, designed to take on Apple and Commodore with something more affordable, and in color no less.
The CoCo provides a sizeable library for any 8-bit enthusiasts. Unfortunately, running this software can be a tricky process, so we will guide you through the steps needed to emulate this groundbreaking machine. –JOHN KNIGHT
1
DEVELOPMENT AND RELEASE
The CoCo began life as a VideoTex terminal designed to provide farmers with access to real-time agricultural information. The VideoTex terminal used Motorola’s Video Display Generator (VDG) chip and 6809 processor. Although the VideoTex was commercially unsuccessful, in 1980, it was combined with newer hardware to form the basis of a new color computer.
>> Tandy removed the VideoTex’s internal modem and added expansion for ROM cartridges, cassette input, serial I/O, and joystick ports. Video output was based around a standard TV set.
>> The first TRS-80 Color Computer launched in September 1980, for an introductory price of $399. Although the base model was quite cheap, the system relied heavily on expensive peripherals and users even had to supply their own tape drive.
>> Despite its name, the CoCo shares nothing in common with the original TRS-80 and is not backward compatible.
>> The CPU is a Motorola 6809E clocked at 0.895MHz. Sound is basic, being handled by a single-channel 6-bit DAC, powered by the CPU. Graphically impressive for the time, the CoCo is capable of nine colors and a maximum resolution of 256x192.
>> The base specs provided 4KB of RAM and Color BASIC, a Tandy implementation of Microsoft BASIC, in an 8KB ROM.
>> Models with 16KB (and later 32KB) of RAM were also available, with the option of Extended Color BASIC.
2
SOFTWARE
The CoCo software library has a different emphasis from many systems. It featured better educational software than Commodore’s machines, though its limited 32-column text mode meant the machine wasn’t suited to business applications.
>> For anyone looking to get into BASIC programming, the CoCo is an excellent place to start. There are plenty of books and magazine listings, and Tandy’s own ‘Getting Started With Color BASIC’ manual was considered one of the best in the business.
>> For some gaming highlights, DungeonsofDaggorath (1982) is a particularly famous first-person dungeon crawler, with real-time gameplay and unique line graphics. Skiing (1980) is a personal favorite—its first-person 3D perspective is surprisingly effective, despite the machine’s graphical limitations. Zaxxon (1983) is a solid port and one of the system’s better titles.
>> Other games included TimeBandit (1983), SpeedRacer (1984), and Pitfall2 (1985), which is a great update on a classic. For titles that push the system harder, check out Thexder (1987), Springster (1987), King’sQuestIII (1988), and Rampage (1989).
>> Most software titles and reference manuals can be found at the excellent colorcomputerarchive.com website.
3
LEGACY
In 1983, the CoCo was upgraded to the Color Computer 2. These new models brought drastic price reductions and featured either 16 or 64KB of RAM.
>> The case was re-designed: consolidated chipsets allowed for a smaller footprint, and the iconic silver styling was replaced by beige. Later models, named the Tandy Color Computer 2, featured full-travel keyboards.
>> In 1986, the Color Computer 3 pushed CoCo architecture to its limits. A newer variant of the 6809 CPU allowed for twice the clockspeed and the CoCo came with 128KB as standard, upgradeable to 512KB.
>> The Advanced Color Video Chip allowed features such as memory bank switching, RGB output, 80 column text, 16 colors on screen from a palette of 64, and resolutions up to 640x192. Extra keyboard buttons were added, cursor keys were grouped in a more conventional layout, and more priority was given to Microware’s OS-9.
>> In October 1990, Tandy discontinued the line, though stores continued to sell CoCo stock. As for how many they sold, Tandy was notoriously tight-lipped on figures.
4
EMULATION
The easiest emulator is VCC, which emulates the CoCo 3, but its interface can be obtuse. VCC only supports Windows, but Linux users can run VCC through Wine or OVCC. Still, it can be a pain to install. You can try MAME, though you will need system ROMs.
>> The VCC’s Github page provides a self-extracting Windows executable, with a simple installer interface that will automatically create entries in your system menu.
>> Once you open the application, we recommend switching VCC’s keyboard layout to a modern PC key mapping, otherwise entering BASIC commands will be a nightmare.
>> From the main menu, choose Configuration > Config. In the new Options window, open the Keyboard tab, and in the Select Keyboard Mapping field, click Natural. There, it’s worth opening the Joysticks tab to define how you will control your games.
5
LOADING CARTRIDGES
Unlike the other storage mediums, loading cartridges is easy. Just choose Cartridge > Cartridge > Load Cart.
>> Select your cartridge image from the file browser, and the emulator will reset, loading the cartridge automatically.
6
LOADING TAPES
Loading tapes isn’t difficult, but it is unintuitive. Open the Options window by selecting Configuration > Config, then open the Tape tab. Click Browse to open a cassette image file, then click Apply. It’s worth keeping the Options window open and moving it to one side because you’ll need to use it again.
>> Click on the main window, and in the BASIC prompt, enter: CLOADM
>> The emulated Tandy will now wait for you to press Play on the tape recorder—in the Options window. Press Play and the BASIC prompt will flash an F character to indicate the program
is loading. Once finished, the prompt says “OK”, and has a blinking cursor.
>> To run the program, enter:
EXEC
7
LOADING DISKS
When it comes to loading disks, VCC’s method is bonkers. This also requires BASIC commands.
>> On the original CoCo, disk drives connected via a cartridge interface, so VCC does something similar. When you first start VCC, there will be no apparent way to load disks. But if you load a cartridge, the file browser opens in VCC’s installation folder, with the file fd502.dll.
>> When you open the Cartridge menu, there will be a series of floppy drive sub-menus called FD-502. Load a disk in the first drive by clicking Cartridge > FD-502 Drive 0 > Insert. Select your file and you’ll be taken back to the emulator screen.
>> To load a program, browse the disk and look for the filename. Browse the first floppy drive by entering:
DIR 0
>> In the output that follows, look for either BAS (basic programs) or BIN (binary programs) files. If there are any BASIC programs, try loading these first.
>> To load a BASIC program, enter the command:
RUN “0:BOOT.BAS”
>> We used BOOT.BAS as an example, but replace this filename with whatever you have on your disk image.
>> If there are no BASIC programs, run a binary program by entering (using Zaxxon as an example):
LOADM “0:ZAXXON.BIN” : EXEC