nfg.forums

Dear forum, I am happy to announce that my static RAM expansion project is complete!

After trying to find reasonably priced and available RAM expansion, I decided to design and build my own. This board is based on fast and modern static RAM and is an open design available at github.

Feel free to build your own or order from me.

Prices without shipping are as follows:
2MB - 45EUR (Plays all games from Games3 directory)
4MB - 60EUR
6MB - 75EUR
8MB - 90EUR

PM me for shipping quotes.

PS: Don't trust the silkscreen on the boards in pictures.

Here are some pictures of the 8MB dev board. Production version will not have the debugging connector on top right.


Memtest success:


EDIT: Changed prices

Amazing timing, I was just about to start looking into doing one myself based on some schematic I found in files.

I'll send you a PM.

Really appreciate your work here and thanks for making it an open design as well.

If I hadn't bought an xsimm, I would have definitely had one of these!

Nice work, well done!

This is my first ever electronics design from scratch. And my first programmable logic work.

Any feedback would be welcome. I know that for next iteration, I will route another address pin to support older machines having 1MB built in memory.

Wow! Nicely done! And yeah, thanks for making this open. PMing you now with interest.

Great work. Sent you a PM.

Boards arrived today, working well.

Thanks for all the interest! Pitty you could not test it on a XVI. I need to look into overclocking my Expert to test 16Mhz as well

I have attached a pic of both of your boards:

Crossing fingers I'll get the XVI going again in the next few days - I "think" I have an idea where the issue is and will be starting to test to try to resolve from today.

And yes the XVI is going again.

Ran memtest68k at 16MHz and it passed 100%.  Took a couple hours to run but I figured it's more thorough than MTEST.

Great to hear that! I will update the github page.

Quote from: watto on September 20, 2020, 10:22:33 PMAnd yes the XVI is going again.

Ran memtest68k at 16MHz and it passed 100%.  Took a couple hours to run but I figured it's more thorough than MTEST.

Could you test with Geograph Seal? If the memory is not stable at 16mhz you will get a bus error

Yes, I played it for a while just yesterday.  No issues.

Nice project!

Pm sent.

Got the board today -- will check it out this weekend. Thanks @stas2k!

You are welcome! If anyone wants more, I have a hefty stock now.

Installed the 4MB version of this board from @stas2k in my ACE today and it works great. Finally played Daimakaimura on my X68k! Big thumbs up for this board.

Great! I will add the ACE system to the compatibility list on github.

Daimakaimura is hardcore difficult, it looks so cartooney, I did not expect that. We mostly play Final Fight whenever my brother visits, and still are not able to complete the game with 2 players.

Amazing work. I'll send you a PM once I get my Compact and my 68030 up to snuff to check for compatibility.

sent you a pm for a 6mb board. -Matthew

I've sent to you a PM for a 8MB board. Thanks!

Received my 4MB board today, great product! So cool that this kind of stuff is produced today again. Great work.

Wow interested in one PM sent

Thanks

Just curious to see if anyone could test the game Cybercore with this RAM board and see if there is audio crackling during the intro. My setup to reproduce this issue was: XVI + XSIMM VI + 4MB PIO RAM board. The 4MB PIO RAM board was causing the issue so I've since removed it. Wondering if this board has such issues or not. Thanks.

Payment sent to stas2k with thanks

And that was the last board I had. Next ones will be redesigned a bit, without buffers and GAL in a smaller package.

Thanks to everyone who ordered, I did not expect so much interest

Hello all,
Unfortunately I found this post long after finding the github, I could've order the project directly from you my friend and save time and money. Anyway I've ordered and got some v1.2 pcb and have the ic's coming from mouser loaded with taxes... My problem is I can't open the GitHub project on any version of kickad, I've tried from v4 to the latest 5.1 and all I get is errors. Can you please tell me what version you used so I can open it and study the schematic, the capacitors value, and the jumpers settings for the 4mb version. Thank you in advance.

I probably should have linked this thread to github.

You need to use kicad 6 preview versions as I am using git builds. The new version has features that I could not just skip.

There are also gerber files attached in github releases if you do not want to do that. I have also attached the JED file to program the GAL as well.

Already have the pcb gerbers where fine, will try new version thank you.

I just want to leave this message here telling you all that I've ordered a 8MB Galspanic and it worked like a charm on my x68000 XVI. Thanks to stas2k.

@stas2k, I want to buy an 8MB card, I sent PM. Tks

Thanks @stas2k

I have installed the expansion and tested, all working perfectly.

You have been very kind and helpful.

Thank you.

Video:

https://www.nightfallcrew.com/download/x68k-galspanic-sf.mp4

The new board design looks nice!

@stas2k I want to buy the X68000 memory exp board ! Please contact me !

I would like to buy one of these for my X68000 Expert HD. Does anyone happen to have Bill of Materials (B.O.M) for the bare PCB?

(Edit): My Friend helped me find the Bill of Materials (B.O.M). Here's the link to what's needed if you buy a barebones PCB from eBay or PCBWay.

SN74AHCT245DW Buffer Chips: https://www.digikey.com/en/products/detail/texas-instruments/SN74AHCT245DW/375865

Ceramic Capacitors: https://www.digikey.com/en/products/detail/taiyo-yuden/EMK107B7104KAHT/7404019

Electrolytic Capacitors: https://www.digikey.com/en/products/detail/nichicon/UPW1A221MED/589481

ATF22V10C-10PU DIP-24 #A2 Address Decoder GAL Chip: https://www.ebay.com/itm/184367009522 (You can also get this on DigiKey, but it's on Backorder.)

CY62167EV30LL-45ZXI (5 Piece Lot) SRAM Chips: https://www.aliexpress.com/item/4000117073914.html? (According to my friend, this chip is out of production. AliExpress is the only way to get it.)

Here's the DigiKey short order my friend sent me. It contains right amount of Capacitors & Buffer Chips to get. https://www.digikey.com/short/8cz49ndn

Big thanks to my friend Dan for helping me assemble the Bill of Materials.

Sorry all, I have been away from the forums for a while. I still have remaining stock and sent out messages to those who wrote to me before.

If you did not hear from me, I am out of boards and will not be producing more. This is due to 3x price jump on the SRAM chip prices.

@PsychoLavos, your BOM is not correct on the SRAM chip area. You have 3.3v modules, and those will not be happy to work on a 5v system that is X68000. Mind you, it might work, but might also damage your precious system due to excessive current draw on bus pins. You will also have to program the GAL chip with JED files I published on github.

I do have around 8 blank PCBs of the v2 version to sell, so feel free to contact me for those.

Sorry to hear you won't be making more. If you're all sold out would you still be able to send me a new GAL for my board configured to 8MB internal ram installed?

I will check my stock to see if I have GALs in DIP package. Maybe you have a friend with a programmer to flash these chips? Then we don't have to ship these chips around

I don't unfortunately. I posted a wanted ad in the BST forums but no replies yet. I would be happy to cover the cost of shipping though

Quote from: stas2k on March 03, 2022, 10:49:53 PMSorry all, I have been away from the forums for a while. I still have remaining stock and sent out messages to those who wrote to me before.

If you did not hear from me, I am out of boards and will not be producing more. This is due to 3x price jump on the SRAM chip prices.

@PsychoLavos, your BOM is not correct on the SRAM chip area. You have 3.3v modules, and those will not be happy to work on a 5v system that is X68000. Mind you, it might work, but might also damage your precious system due to excessive current draw on bus pins. You will also have to program the GAL chip with JED files I published on github.

I do have around 8 blank PCBs of the v2 version to sell, so feel free to contact me for those.

Noooooooooooo

I brought a board of you some time ago love it, so happy I was thinking of getting another x68000 as one is not enough. don't supposed you will change your mind ??