Hi all...

I want to create my own megarom-cartridges(256kb or 512kb) and release our games on it. (not the msxdev'08 version ofcourse, but we're building a sequel right along with it...because the msxdev'08 specs(128kb) limits us to do the complete design in one game)

I know my electronics so that's not a prob. but was wondering if someone already has or knows where to get the design of a megarom-cartridge. no SCC (persé..but is no prob if included) cause we want to be able support other sound also..moonsound..fm-pac etc

If searched the forum and found some topics...but not one that's really complete..and also links to japanese articles...well I dont speak japanese

I dont want to butcher old konami-roms...so no converting
And dont want anyone else (like shockware label) to build it for me

I really would like to do it myself....cause it's ofcourse also a hobby of mine....

Can anyone give me a boost in the right direction...pretty please???

Is the DIY aspect the main reason why you're opposed to, say, Shockware? Most people are all too happy to be able to 'outsource' this hardware work to specialists..

Indeed. First make sure that you've got a finished game. Production comes later.

Most people seem to use flash chips nowadays anyway.

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Is the DIY aspect the main reason why you're opposed to, say, Shockware? Most people are all too happy to be able to 'outsource' this hardware work to specialists..

Dont like people making money of my back...

And anyway just want to make three carts for ourselves...

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Indeed. First make sure that you've got a finished game. Production comes later.

I think that's up to me I think...when to do what and such...

I can try and figure out the design myself but that would take quite some time and instead of reinventing the wheel so to speak...maybe people have done it already and are willing to share...their knowledge...

cause one way or another I will make it happen...I always do...

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Dont like people making money of my back...

With Shockware, that is not the case. You get a percentage of the sale price, and don't have to bother with production and distribution costs. I'd say it is an ideal concept for game developers. Of course, you can do it all your way, because it is a hobby and a free world, but you'll end up spending more time and money than having someone doing it for you. I like to think that everyone has got his expertise in one way or another.

btw, everyone is making money of your back, the supermarket isn't charity.., and you do realize what % of your car gas goes to the government?

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And anyway just want to make three carts for ourselves...

I can make those three cartridges if you want. And don't need to lose/transfer the distribution rights.

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Can anyone give me a boost in the right direction...pretty please???

Just check ESE RAM Disk scheme (ERAM-CI.SR7 image). It is enough to figure out how to make your own cartridges. Replace the SRAM ICs with EPROM, flashROM, ROM or whatever you want. Also, you can replace the ASCII mapper with a CPLD.

make a 128k mapper is easy , open a megarom zemina cartridge you find 1x74LS02 1x74LS670 1x 27C010

make a 256k is possible if added a 74LS670 and replace 27C010 by a 27C020

make a 512k is possible if added a 74LS670 and replace 27C010 by a 27C040

this mapper is a konami mapper 4000 6000 8000 A000

good luck

It has been done before, in the way Jipe describes. Look for the design of the MegaRam, several versions available. You can replace dynamic RAMs with a large SRAM nowadays.

"....if someone already has or knows where to get the design of a megarom-cartridge"

You mean you want to build your own mould to make the plastic housing? That would mean investing around 10000 euros for the tool! And probably a minimum order quantity of 4000 sets.
If you want to use a rapid prototyping technique (no metal tool) you would be looking at around 40 euro per empty cartridge!
I can draw you a 3D CAD file (I am working in the design / plastic business) but what would your idea / room for investment for it?

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btw, everyone is making money of your back, the supermarket isn't charity.., and you do realize what % of your car gas goes to the government?

YEAH but they're not making money off of anything spawned out of my creativity...

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Quote: And anyway just want to make three carts for ourselves... I can make those three cartridges if you want. And don't need to lose/transfer the distribution rights. Quote: Can anyone give me a boost in the right direction...pretty please??? Just check ESE RAM Disk scheme (ERAM-CI.SR7 image). It is enough to figure out how to make your own cartridges. Replace the SRAM ICs with EPROM, flashROM, ROM or whatever you want. Also, you can replace the ASCII mapper with a CPLD.

these files are full of jibberish...? probably ..japanese text.. Is there a translated version perhaps?
how did you figure it out from this text? I can't make out what's what..

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make a 128k mapper is easy , open a megarom zemina cartridge you find 1x74LS02 1x74LS670 1x 27C010 make a 256k is possible if added a 74LS670 and replace 27C010 by a 27C020 make a 512k is possible if added a 74LS670 and replace 27C010 by a 27C040 this mapper is a konami mapper 4000 6000 8000 A000 good luck

thx..will have to search for one of those cartridges then..