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View topic - I Designed A Digital Mockup For The Ultimate Mark III/ Master System To Megadrive/Genesis Adapter

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  • Joined: 27 Apr 2023
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I Designed A Digital Mockup For The Ultimate Mark III/ Master System To Megadrive/Genesis Adapter
Post Posted: Fri Apr 28, 2023 12:16 am
Please forgive the rough quality of the image as I'm not good with image editing. It has a TMS9918 built in to allow SG-1000 games to be playable on a Megadrive/Genesis. Feel free to turn this into a real product & all i request in return is a free unit
Mockup Part 1.png (841.82 KB)
Mockup Part 1.png

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  • Joined: 05 Sep 2013
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Post Posted: Fri Apr 28, 2023 11:47 am
Why don't you also add an YM2413? It should take 1 minute.
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  • Joined: 14 Oct 2008
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Post Posted: Fri Apr 28, 2023 1:44 pm
Would putting a TMS9918 in a cartridge actually do anything in real hardware?
Was the Genesis designed to be expanded that way? I know the 32X is a cartridge device that can expand the video capabilities, but that is only done through an extra video cable.
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Post Posted: Fri Apr 28, 2023 2:21 pm
Indeed, it would actually have to be a piggy-back complete SG-1000 for this to work, it’s not even remotely possible. You may as well paste a picture of a PS5 on there.
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Post Posted: Fri Apr 28, 2023 6:06 pm
Is there even any way to only borrow the Megadrive's Z80? As far as I can tell, there's no way for the cartridge to preempt the system-internal VDP, so although we could add a TMS9918 and 16KB DRAM and an entirely separate video output, I don't think the Z80 could ever read from the on-cart TMS9918.

Or am I forgetting something?
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Post Posted: Tue May 02, 2023 9:15 am
the main issue on having a TMS chip on the cartridge is that the chip won't be able to access the system's video RAM from there

the OP was probably just kidding.

right?
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