N64 Memory Pak from scratch

Ever had your N64 memory pak battery die and lose all your precious saves from your childhood games? Or purchase an aftermarket pak only for it to arrive broken? I have, which is why I designed my own N64 memory pak. I used an FM28V020 FRAM IC which does not require a battery to retain the saves and according to the datasheet it will last 150 years! Most FRAM modded paks I see use parts harvested from an original nintendo memory pak so instead I designed my own pcb so I can build the whole device with off-shelf purchased parts.

The pcb will even fit perfectly in an original nintendo memory pak shell in that case that you want to swap them. I modeled the memory pak shell to be 3D printed.

The memory size is 256KB, which is the same size as the original pak. Due to the memory bank size, it is not possible to use a larger memory. Some aftermarket paks that advertise extra memory, quite literally have two memory ICs inside with a switch to activate either chip.

https://www.ebay.com/itm/254859745348

I think this has turned out to be a good product that is needed in the market flooded with over priced FRAM modded paks so I will be selling them on ebay. Get yourself a reliable memory pak that will keep its saves for generations!

6 thoughts on “N64 Memory Pak from scratch”

  1. Ordered, excited to finally be worry free with my n64 saves. Seems serendipitous that I find out about FRAM modded paks after my pak died, and I find your product on Ebay.

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  2. While this seems like a good idea, I think the execution isn’t perfect. The Ramtron chips that are used in it seem to have an address access time of 140ns (if the CE pin isn’t used, if I’m reading the datasheet correctly – and from what I can tell it’s not specifically connected to any thing except maybe ground) , which may be too slow for some N64 games (the original Sharp SRAM chips seemed to have a 70ns access time, and one 3rd party SRAM pak has a Samsung chip with an 85ns timing). Notably, my copy of Turok 2 complains that the save files written to my FRAM pak are corrupt, despite multiple attempts at saving new ones. It (claims to) write fine every time, though.

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    1. Very observant. I made a test and I had the same results on turok 2, it didnt make any difference if CE is ground driven or by the controller. I recently redesigned the memory pak project using a new circuit and it does work on Turok 2 I just tested. It’s a good test so thank you for noting that. Hopefully I will finish the project soon and share it.

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      1. Excellent, glad to hear it. I suspected that there were some timing issues when I was playing through Turok 1, because it would randomly complain about corrupt save files but then would load them without issue if I immediately tried again (seemed like 1 our of every 15 attempts). Of course Turok 1 uses a reasonable 16 blocks – Turok 2’s 90 (!) blocks really doesn’t help anything.

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      2. I would figure this only has to do with the N64 controller interface. But perhaps the game can determine how much data is read/write at a time. I am going to look into this and test every game. I just tested Mario Kart which is 123 pages, it seemed to work on both my custom paks.

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