WindDrake Posted August 20, 2021 Share Posted August 20, 2021 Hey all. I'm normally over on the arcade side (same username on KLOV & ArcadeControls) but I've finally got a console project. After seeing how much that Ultra CD RAM Cart costs or the price of an original cart, I started working out the schematic from my Sega RAM cart. Then I stumbled onto l_oliveira's work on a RAM Cart over on the NFGgames forum. With a couple days of schematic drawing and PCB layout behind me, here's what I've got so far. Should be finalizing this by the end of the weekend and ordering my PCB's on Sunday. I've got a label worked up as well, just need shells, assuming I don't just print them. This is all totally open-source, with all the files available at github.com/WindDrake/SegaCD_Ramcart 4 Quote Link to comment https://forums.atariage.com/topic/324125-sega-genesis-md-cd-ram-cart-open-source/ Share on other sites More sharing options...
WindDrake Posted September 4, 2021 Author Share Posted September 4, 2021 Hey all! Boards came in today. Had a minor issue with the '138 decoder having A20/A22 swapped by accident,. It after a quick wire patch everything is working nicely! I've already corrected the PCB files (v1.1) on GitHub to fix this. This cart also doesn't have the Dark Wizard save glitch like the Castlemania Games Ultra cart. New cart label graphics will get uploaded to GitHub soon. I'm also working with the folks at RetroGameCases to offer the labels predone. Quote Link to comment https://forums.atariage.com/topic/324125-sega-genesis-md-cd-ram-cart-open-source/#findComment-4898977 Share on other sites More sharing options...
copperboy Posted September 5, 2021 Share Posted September 5, 2021 What's this? Is it a DRAM chip and it needs electricity to keep its memory? Also, you need something to write the game binary to the RAM chip? Quote Link to comment https://forums.atariage.com/topic/324125-sega-genesis-md-cd-ram-cart-open-source/#findComment-4899964 Share on other sites More sharing options...
WindDrake Posted September 6, 2021 Author Share Posted September 6, 2021 (edited) 9 hours ago, copperboy said: What's this? Is it a DRAM chip and it needs electricity to keep its memory? Also, you need something to write the game binary to the RAM chip? Battery-backed SRAM, actually. This is a open-source implementation of the Sega CD Back-up RAM Cart. You can move savegames from the internal memory of the SegaCD to the RAM Cart for long-term backup, and many games supported saving directly to the cart. In the case of Lunar Silver Star Story, it actually requires the cart to access Act 3, due to the savegame size being larger than the internal save RAM on the Sega CD. Edited September 6, 2021 by WindDrake Quote Link to comment https://forums.atariage.com/topic/324125-sega-genesis-md-cd-ram-cart-open-source/#findComment-4900315 Share on other sites More sharing options...
copperboy Posted September 6, 2021 Share Posted September 6, 2021 16 hours ago, WindDrake said: Battery-backed SRAM, actually. This is a open-source implementation of the Sega CD Back-up RAM Cart. You can move savegames from the internal memory of the SegaCD to the RAM Cart for long-term backup, and many games supported saving directly to the cart. In the case of Lunar Silver Star Story, it actually requires the cart to access Act 3, due to the savegame size being larger than the internal save RAM on the Sega CD. I see. I didn't know that product existed from SEGA. I guess you have made an equivalent version of it with similar chips. I assume the SEGA CD device can somehow identify that this card is inserted and copy the entire RAM to this cartridge. Is there a way to save standard SEGA Genesis/mastersystem games to something? Is there a way to save NES games to something? As a kid, I use to set a game on pause and leave the NES "ON" for hours, until I came back. I got tired after playing it for 2 -3 hours. Quote Link to comment https://forums.atariage.com/topic/324125-sega-genesis-md-cd-ram-cart-open-source/#findComment-4900683 Share on other sites More sharing options...
WindDrake Posted September 7, 2021 Author Share Posted September 7, 2021 6 hours ago, copperboy said: I see. I didn't know that product existed from SEGA. I guess you have made an equivalent version of it with similar chips. I assume the SEGA CD device can somehow identify that this card is inserted and copy the entire RAM to this cartridge. Is there a way to save standard SEGA Genesis/mastersystem games to something? Is there a way to save NES games to something? As a kid, I use to set a game on pause and leave the NES "ON" for hours, until I came back. I got tired after playing it for 2 -3 hours. The SegaCD/MegaCD goes looking at a specific address during bootup, and if it gets the correct byte back, it'll identify the cartridge and it's SRAM size. Not sure on the other questions - beyond the scope of this thread. Quote Link to comment https://forums.atariage.com/topic/324125-sega-genesis-md-cd-ram-cart-open-source/#findComment-4900895 Share on other sites More sharing options...
+-^CrossBow^- Posted September 8, 2021 Share Posted September 8, 2021 Now that you have this working, what about a version that use FRAM instead so that no battery is required? Quote Link to comment https://forums.atariage.com/topic/324125-sega-genesis-md-cd-ram-cart-open-source/#findComment-4901904 Share on other sites More sharing options...
WindDrake Posted September 8, 2021 Author Share Posted September 8, 2021 1 hour ago, -^CrossBow^- said: Now that you have this working, what about a version that use FRAM instead so that no battery is required? Ramtron/Cypress never made a 512k/4mbit 5v Parallel FRAM, sadly. Biggest around seems to be the discontinued FM1808, which is 32k/256kbit (stock cart was 128k/1mbit). There's I2C FRAM that big, but they are $50+ and would need a whole memory manager sitting between the parallel and serial bus. Not really worth it. Quote Link to comment https://forums.atariage.com/topic/324125-sega-genesis-md-cd-ram-cart-open-source/#findComment-4901959 Share on other sites More sharing options...
+-^CrossBow^- Posted September 8, 2021 Share Posted September 8, 2021 59 minutes ago, WindDrake said: Ramtron/Cypress never made a 512k/4mbit 5v Parallel FRAM, sadly. Biggest around seems to be the discontinued FM1808, which is 32k/256kbit (stock cart was 128k/1mbit). There's I2C FRAM that big, but they are $50+ and would need a whole memory manager sitting between the parallel and serial bus. Not really worth it. I've actually got a small stock of actual Ramton FM1808 chips. I have them for Saturn FRAM upgrades. Quote Link to comment https://forums.atariage.com/topic/324125-sega-genesis-md-cd-ram-cart-open-source/#findComment-4901976 Share on other sites More sharing options...
+Yurkie Posted September 17, 2021 Share Posted September 17, 2021 Very cool WindDrake Quote Link to comment https://forums.atariage.com/topic/324125-sega-genesis-md-cd-ram-cart-open-source/#findComment-4906896 Share on other sites More sharing options...
WindDrake Posted November 13, 2021 Author Share Posted November 13, 2021 More progress on this today, now that the labels have finally come in. First up, here's a 1.0 board with the line swap fix. Pretty low-impact, and it's been fixed on the 1.1 board. Here's the labels, printed by fireandclarity on Etsy. Labelled cart. Real deal Vs. My RAM Cart At this point I'd consider the project complete. Quote Link to comment https://forums.atariage.com/topic/324125-sega-genesis-md-cd-ram-cart-open-source/#findComment-4945442 Share on other sites More sharing options...
+-^CrossBow^- Posted November 13, 2021 Share Posted November 13, 2021 1 hour ago, WindDrake said: More progress on this today, now that the labels have finally come in. First up, here's a 1.0 board with the line swap fix. Pretty low-impact, and it's been fixed on the 1.1 board. Here's the labels, printed by fireandclarity on Etsy. Labelled cart. Real deal Vs. My RAM Cart At this point I'd consider the project complete. Awesome! How can I get one? Quote Link to comment https://forums.atariage.com/topic/324125-sega-genesis-md-cd-ram-cart-open-source/#findComment-4945490 Share on other sites More sharing options...
WindDrake Posted November 15, 2021 Author Share Posted November 15, 2021 On 11/13/2021 at 5:52 PM, -^CrossBow^- said: Awesome! How can I get one? I didn't really plan to offer these other than as a gift to the community, hence the open sourcing. I had one spare cart, but somebody snapped it up before it was even assembled. I'd love to offer a run of them or something, but I don't have enough gaps in my schedule to pull it off. Sorry! Quote Link to comment https://forums.atariage.com/topic/324125-sega-genesis-md-cd-ram-cart-open-source/#findComment-4946782 Share on other sites More sharing options...
+Yurkie Posted November 15, 2021 Share Posted November 15, 2021 I am the lucky guy that is getting the extra from WindDrake. The Ultra seems to be back for $69.99 not sure if the Dark Wizard save is fixed. https://castlemaniagames.com/products/ultra-cd-ram-cart Quote Link to comment https://forums.atariage.com/topic/324125-sega-genesis-md-cd-ram-cart-open-source/#findComment-4946811 Share on other sites More sharing options...
RevQuixo Posted March 8, 2022 Share Posted March 8, 2022 https://twitter.com/revquixo/status/1501190386127183874 @WindDrakeMight be worthwhile to indicate that the current CastleMania version appears to be safe. Quote Link to comment https://forums.atariage.com/topic/324125-sega-genesis-md-cd-ram-cart-open-source/#findComment-5017709 Share on other sites More sharing options...
WindDrake Posted March 8, 2022 Author Share Posted March 8, 2022 4 hours ago, RevQuixo said: https://twitter.com/revquixo/status/1501190386127183874 @WindDrakeMight be worthwhile to indicate that the current CastleMania version appears to be safe. I can't edit posts that old, but thanks for the heads-up. Glad they fixed it. Still seems like a lot of money for a cart. Quote Link to comment https://forums.atariage.com/topic/324125-sega-genesis-md-cd-ram-cart-open-source/#findComment-5017863 Share on other sites More sharing options...
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