Colecovision > MSX

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By gdx

Enlighted (4284)

gdx's picture

15-03-2014, 02:33

I do not know your SN76489AN emulator. I used Marcel de Kogel's sound routine from Mission emulator. This routine works very well and allows to play the sound on 4 SCC voices when necessary. This routine produces sounds with a variable number of loops. It slows down more or less depending on the number of loops.

With this new cartridge, sound routines are original so there is no slowdown and the sound is identical to the original games.

The best way to make a compilation is to make a BIOS that contains all the routines that change and alter calls in games. Otherwise the dip switches is an interesting idea.

By Maggoo

Paragon (1212)

Maggoo's picture

15-03-2014, 02:46

Wouldn't a Megarom Mapper be easier to implement than dip switches? I once made a very simple Rom menu that merges multiple Rom games into a Megarom. The first Megarom page was the menu and basically only allowed to select a Megarom page (or 2 for 32kb Roms) and launch the Rom program in that page. I use it in the Megaflashrom SCC+ (saves me the trouble of having to load the games or use a disk based menu each time or use a keyboard). I would imagine that the same principle could be used here too? I don't know much about the Coleco's system but I seem to remember that most Roms were 16 or 32 kb also right?

By ericb59

Paragon (1046)

ericb59's picture

15-03-2014, 08:36

@Maggoo, most of the Coleco Rom conversion GDX made are 64k large.
Is it possible to adapt your menu for 64k Roms ?

If you have the menu, I can produce cartridge up to 8Mbits, which is sufficient to handle near all coleco conversions I thinK.

By ARTRAG

Enlighted (6502)

ARTRAG's picture

15-03-2014, 10:03

All depends on the mapper you can use an on the memory layout gdx's roms expect to use

By gdx

Enlighted (4284)

gdx's picture

15-03-2014, 10:31

Coleco's Roms are 16, 24 or 32 KB but I add the BIOS and many routines. It is possible to reduce the size but it takes time. The games are not disassembled and a small change can upset the interruptions. My main goal was to run the games. We can do a few cartridges just to please the fans. The number will be very limited.

By hbarcellos

Hero (625)

hbarcellos's picture

15-03-2014, 11:51

gdx wrote:

I do not know your SN76489AN emulator. I used Marcel de Kogel's sound routine from Mission emulator. This routine works very well and allows to play the sound on 4 SCC voices when necessary. This routine produces sounds with a variable number of loops. It slows down more or less depending on the number of loops.

With this new cartridge, sound routines are original so there is no slowdown and the sound is identical to the original games.

I made my emulation routines from scratch. They're publicly available somewhere. I think mars hosted them.
Personally I think it's a waste of HW to include the original SN chip for that. If I remember correctly, the tones are absolutely equal, but MSX noise generator has less variations.
Take a look here: http://www.youtube.com/watch?v=ErvQtdttV40
AY-3-8910 has 32 different noise tones, and SN76489AN has more.
I was planning to map SN76489AN tone to the nearest AY-3-8910 noise tone. I bet almost anyone would notice a difference. But in the end, I was lazy enough just to transform noise to tone. If you take my Tutankham conversion and use the BOMB, you'll notice that the sounds are all there, but different.

Besides, as far as I can remember, my conversions were never more than 32k. I packed the Coleco BIOS (which is very small) and unpacked it to ram. Some games didn't even used the BIOS, so, with a little bit more effort, I would be able to remove it completely...
Why don't you take a look at my source code?

Best Regards,
Heitor.

By hbarcellos

Hero (625)

hbarcellos's picture

15-03-2014, 11:55

Maggoo wrote:

Wouldn't a Megarom Mapper be easier to implement than dip switches? I once made a very simple Rom menu that merges multiple Rom games into a Megarom. The first Megarom page was the menu and basically only allowed to select a Megarom page (or 2 for 32kb Roms) and launch the Rom program in that page. I use it in the Megaflashrom SCC+ (saves me the trouble of having to load the games or use a disk based menu each time or use a keyboard). I would imagine that the same principle could be used here too? I don't know much about the Coleco's system but I seem to remember that most Roms were 16 or 32 kb also right?

Absolutely better and more elegant. I also hate dip switches.
Im not a HW expert but, I suppose we would need a "megarom mapper" chip inside the cart, right? Those can be bought easily or we would need to destroy some original Konami cartridges?
I can easily create a menu for a multicart with my ROMS. Or even better, I can ask John to create a nice MENU music and Artrag to create some nice visual effects with his (above my level) coding skills, and then this multicart would be EPIC!!

By ericb59

Paragon (1046)

ericb59's picture

15-03-2014, 12:01

If you have the Menu and the Rom...
I have the cartridge set !

This is a Cartridge set handle a EPROM (512k or 1024K) or a Flash Memory (512K).
Mapper is ASCII 8k or ASCII 16K

I'm currently building another cartridge with Konami Mapper with a Falsh Memory (512k)

All is new hardware.
(Not compatible with SCC)

By gdx

Enlighted (4284)

gdx's picture

15-03-2014, 13:12

I compared several games with a AY-3-8910, a SCC and a SN76489AN.
With the AY-3-8910, the sound is often very close but the noise is different. With the SCC, the sound is less accurate but there are the 4 voices. However, games are slower in the two cases.

I have not removed the BIOS because I hoped make a common BIOS but I have not succeeded. I like also to see the coleco's logo on MSX. Smile

Finally, I think we'll do just the memory mapper cartridge with the internal SN76489AN.

By hbarcellos

Hero (625)

hbarcellos's picture

15-03-2014, 16:18

ericb or anyone else that would like to launch a cartridge with my roms:
apart with the original copyright (ie Parker Brothers), from my work, they're completely free. I don't demand any payment, royalty, free cartridges or discount on cartridges. Nothing.
I can even help creating a menu suited for my 32k roms for any kind of hardware mapper or even changing/adapting some of the roms.
All I ask is to put the name of my alter-friend, who converted the roms, somewhere in the package,and, a chance to be able to buy the physcical item (in case of a limited batch).

For some games, like Tutankham, a friend of mine even created some artwork, trying to copy the original konami style of the80's. those are also freely available.

just contact me for details: hbarcellos@gmail.com

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