Dragon Multi Cartridge version 1.6 (Rolo)

From The Dragon Archive


This is Dragon multi cartridge version 1.6 for Dragon (TANO) 32/64. It is a minor update of version 1.5. Functionally the same, but a little bit smaller. Display and controls now are in horizontal orientation. The PCB is mounted onto a solid aluminum plate, which makes it rugged and provides a stable seat in the slot, even when operating the controls. The dimensions are small enough making it possible, to build the cartridge into a standard ATARI VCS/2600 shell.

This device is exclusively designed for cartridge ROM programs, not for cassette or floppy disk programs.

It holds up to 64 8k (or 4k/2k) ROM images. It also can store 16k ROM images on adjacent slots. The cartridge uses a single 27C4001 EPROM (512 kBytes).

ROM images are selected by setting two 16 position rotary switches. A two digit LED display shows the number of the selected image (00 ... 63).

Autostart can be switched on and off. An additional switch combines the selected even numbered slot with the following one, providing a 16k slot for larger images.

No loading time:

- hold reset,
- select slot,
- release reset

and the program will launch immediately.

The project started as DRAGON-only, but drifted during the years more and more to be inter-console. In the meantime, most Dragon multi-carts probably are used with different systems.

Dragon ROM images

I successfully tested all the ROM images of this archive.

CoCo ROM images

Most of the CoCo ROM images of the archive are running. Some have to be adapted a little bit, to make them Dragon-compatible. For a list of compatible/modified ROMs please take a look at the forum (->Hints and Tips - Introducing: Dragon multi-cartridge (version 1.0) for ROMs). Modified ROMs can also be found in the forum (->Uploads).


DragonMCv1 6 free400.JPG

Support for other consoles

VideopacExtension Small.jpg

The Dragon/CoCo Multi-cartridge can also be used for other systems. Currently there are Extension Cartridges (adapters) available, which make the cartridge compatible with the VECTREX video game console, with the Odyssey 2/PHILIPS G7000/G7200/G7400 consoles, with the INTERTON ELECTRONIC VC 4000, with the 1292 Advanced Programmable Video System family, made by RADOFIN, ACETRONIC, PRINZTRONIC, HANIMEX, FOUNTAIN etc..., with the Emerson Arcadia 2001 family and its many clones and finally with the EPOCH Super Cassette Vision.
A compilation of rom-files for all the systems can be burned on a single eprom, adding versatility to the device. There are threads in the forum (->sale) showing pictures and giving more information about those add-ons. One multi-cartridge for six systems.


What is a Dragon/CoCo Multi-cart? The Multi-cart was designed to to hold a variety of Dragon/CoCo rom cartridge based programs, which are running directly from the eprom at address range $c000 to $ff00. The cart holds up to 64 8k-roms. It can play roms with a size of 1k to 16k. You simply select a memory slot from 00 to 63, press RESET on your Dragon, and the program launches. This enables you, to use your Dragon simply without further hardware setup: no cables, no drives, no extra PSUs, no controller-carts.

How about disk or floppy programs? Do not run unmodified on the Multi-cart. In many cases, a little loader routine can be put in front of the file, which copies the program from eprom to it’s proper ram-address range and launch. Reloaders are not working this way. Often the first part of the program is just the title screen, which is loaded into video-ram. In this case, this can simply be omitted and the procedure works again.

Why did you make the cartridge? I was looking for one some years ago, couldn’t find one, made one myself. Nowadays there are quite a few cartridges out there.

Why are there different versions of the Dragon/CoCo-Multi-cartridge? I started with version 1.0, using my components in the drawer, learnt some lessons and made version 1.5, realized some improvements and made version 1.6. Then v1.61 ... v1.67 with little changes. And now the new 8-16 and 16-32.

Is there a list of tested roms for the Multi-cart? For Dragon: yes. Please have a look into The Dragon Archive Forums’„Hints and Tips“ section([1]).
Concerning Videopacs, I did not find any non-working standard 1k/2k/4k/8k-roms. Exception Musician, Chess, Basic. So, almost all are running.
Same for Vectrex, but at the moment roms are LIMITED to a maximum size of 16k!
INTERTON VC4000: All games, that do not require extra cartridge RAM are running. Not running: Chess1 & 2, Draughts, Backgammon
EPOCH SCV: All games 8k/16k/32K not needing external RAM. That's the majority of the game library.

Where do I find the Dragon modified roms? They are somewhat scattered and hidden in The Dragon Archive Forums’„Uploads“ section, i. e.: [2] [3] .. .. .. .. [4]

Is there a shell available? No, I changed the dimensions two times. I am mounting the pcbs on protective metal bottom plates. This is sufficient and fits nicely into the Dragons cartridge port. For people, who absolutely want a shell, I recommend to use recycled ATARI VCS cartridge shells and physically modify them with an electric drilling tool, to adapt them for the Multi-cart.

What are these Extension cartridges? Simply adapters/interfaces which you plug between your Odyssey2, Vectrex, INTERTON, 1292 console, Arcadia 2001 console, EPOCH Super Cassette Vision and the Dragon/CoCo Multi-cart. This enables you to use your Multi-cartridge on different systems, which makes it a quite cost-efficient solution.

Do Extension-cartridges store programs, too? No. They are only interfaces.

Which Extension-cartridges are out there? At the moment Odyssey 2 (Videopac), Vectrex, INTERTON ELECTRONIC VC4000, 1292 AVPS, Emerson Arcadia 2001 and EPOCH Super Cassette Vision.

More to come? Maybe yes, from time to time.

Why should I buy a Multi-cart plus an Extension-cart, when I can have dedicated cartridges for all systems? Buy what ever fits your needs the best. If you already own a Dragon/CoCo Multi-cart, then the extensions are expanding your possibilities to use your cartridge. It's a cheap solution which you can for currently six systems, if you swap eprom and extension.

Why do you use eproms instead of a SD-card? I like eproms: they are cheap, easy to put into applications and easy to operate - and very „retro“. Every retro-fan should have an eprom-burner and an UV-eraser. These are cheap tools (on ebay for example) and can be used for all kinds of old computers. Making SD-card based devices is more complicated and usually makes these devices more expensive. Whereas SD-cards are quite useful on dynamic systems, which are getting new software all the time, eproms are good for older systems with a more or less static and limited software library.

Will you never make an SD-cart-based Multi-cart? Maybe sometimes. I don’t know. I think, there already are plenty to be found.

What programs are initially stored on the Multi-cartidge, when delivered? None. Since I do not know the legal situation of all those roms and do not know, which licenses you own, I better deliver an empty eprom. Decide yourself, which roms you may copy and which still are legally protected.

How do I get programs on the cartridge? You need an eprom programmer like the well-known Willem-programmer or any other device. You find plenty of those on ebay. Consider, that some devices need a genuine parallel printerport, which unfortunately passed into oblivion on modern PCs. So maybe look for an USB-only programmer. The programmer burns a single, exact 512k-file (512 x 1024 = 524288 bytes) onto the eprom. You make sure that all program roms are exact 8k or 16k, this means, with the help of an hex-editor you might have to pad zeros at the end of a file. Most roms already have a correct length. Or multiply small files to get 8k-files, i. e. concatenate a 2k-file four times to get an 8k-file and save it. How is concatenating done? On Mac and Linux systems there is a standard shell-command: cat file1.bin file2.bin … filen.bin > result.bin. On Windows there is an ancient DOS-command: copy file1.bin + file2.bin + … + filen.bin result.bin. You simply concatenate exact 8k- or 16k-files until your result.bin is 512k. Take care, that 16k-files are aligned to even 8k-slots. It’s simple and fast. I’m normally making intermediate files first, consisting of eight 8k-roms (64 kbytes). I’m doing this eight times and finally concatenate the eight intermediate files to the final binary. This make debugging and changing roms a lot easier.

How do I get rid of programs into my cartridge? Put your eprom into an UV-eraser box for 15 to 20 minutes.

Can I mix roms of different systems on the same eprom-chip? Yes, any order you like.

What’s the use of the 8k/16k BANK-SIZE switch. It combines two adjacent 8k-slots to a 16k-slot. 16k roms must be aligned. Always even-odd, like 2-3 or 10-11…

What happens if the BANKSIZE-switch is in the wrong position? Position 16k: Small programs, no effect. But you can’t access the odd rom-slots, only even slot-numbers. Position 8k: Large programs won’t work properly.

How do I remember, if a rom is 8k or 16k? Write a list, a table of content.

What’s the use of the AUTOSTART-switch? Dragon/CoCo only: It’s activating/deactivating the autostart feature. For games autostart is fine, but for some development tools memory must be cleared manually before launching.

Which direction do I plug the cartridges in? All cartridges and extensions are always facing up (components and labels on top) or when plugged in vertically, facing to the front of the console.

What happens if I plug it in, in the wrong direction? Errrgh, don’t do it.

What happens, if I selected a wrong rom of another system? No damage. Dragon/CoCo usually crashes. Vectrex runs inbuilt MINESTORM, instead of cartridge game. Odyssey2 does not show „SELECT GAME“, but garbles screen. INTERTON is simply not working. 1292 AVPS is simply not working. Arcadia 2001 is simply not working. EPOCH Super Cassette Vision displays the balloon test pattern.

Can I mix roms of different systems on the same eprom-chip? Yes, any order you like.

Do you have plans to cancel the project soon? No. As long as people are buying cartridges from time to time, I try to always have the needed parts and components at home or produce a new version.

This cartridge has been out for quite some time. There is nothing new? Yes, there now are the the 8k based „8-16“, offering 64 8k memory blocks (512k eprom) and the 16k based „16-32“ offering 64 16k memory blocks (double size 1MB eprom chip). Both cartridges are able to join two adjacent blocks to a single double-size block (8-16: 16k and 16-32: 32k) and both now are able to evenly split a block into a lower and an upper half (8-16: 4k and 16-32: 8k).

What’s that good for? Two different cartridge types better adapt to different console generations. Very old consoles (like INTERTON VC-4000, etc.) used small roms, maybe 2k/4k/8k and the "8-16" is right multi-cart for those, whereas the next generation (VECTREX, SCV) needed larger ones like 8k/16k/32k, which are provided by the "16-32". So finally the Multi-cart also plays 32k-VECTREX games. Storing two small roms into two 4k sub-blocks saves a lot of memory, instead of padding each of them to 8k and using full blocks. In theory, you could store 128 x 2k /4k roms in a 64 block 8-16 multi-cartridge.

How do I keep track of the rom-files? Isn’t that confusing? Yes, it is more complicated than a fixed, equally spaced configuration. Compiling binary burn-files is more work, but it is not THIS COMPLICATED after all. A table of content is recommended. You find an example for an "8-16" in the next section. 16-32 works the same way. Compiling the binary burn file can be a bit tricky. I usually do this in separate steps with the help of folders, which makes it easy to change single roms or remove errors.
I'm using one folder for each console. I'm ordering console roms biggest to smallest, making it easier to ensure parity/oddity of joined blocks.
The command line is your friend. Linux or Mac-users simply use: cat $(ls -S1) > ../consoleXY_part.bin to sort and concatenate all files in current folder to a single file one level above.
I check whether parity for all of those consoleXY_part-files still is fine. If not, I insert or delete roms in the subfolder and do it again.
And finally I join the parts to make the big burn file, i. e.: cat SCVpart.bin VECTREXpart.bin Dragonpart.bin > burnfile.bin

Is it complicated to operate the cartridge? No. Apart from the rotary switches for slot selection, there are three sliding switches on the cartridge:
1. AUTO-START: This one ONLY works for the DRAGON computer. Plugged into a different system it’s doing nothing.
2. BLOCK-SIZE 8k <-> 16k or 16k <-> 32k: That is doing the joining.
3. SPLIT lower <-> upper: This is doing the splitting and it is selecting which rom to start, the lower one or the upper one.

Example: Table of content for 8-16 multi-cartridge

Example TOC MC.jpg

Each line represents an 8k block, which can be split into two 4k blocks (the cells in the illustration), like slot 00 shows. So two independent games in slot 00.
Two 8k lines can be joined to a 16k block, like Arkanoid in slot 02. Lower 8k in even number slot, upper 8k in odd number slot. Notice the light blue and white background.
Slot 04 Berzerk holds a 8k rom.

The new "8-16" and "16-32" cartridges

MC8-16 400px.jpg and MC16-32 400px.jpg