Open Hardware SNES Repro PCB with FeRAM support

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soniccd123
Posts: 23
Joined: Sat Jun 27, 2020 12:01 pm

Open Hardware SNES Repro PCB with FeRAM support

Post by soniccd123 » Fri Nov 13, 2020 1:11 pm

Hello,

In the same vein that I shared my open hardware Genesis repro PCB, I am now sharing my SNES Repro PCB with the community. It is an open hardware project and everyone is welcome to modify and study it as needed. I've tested it extensively in the last months and I think that most bugs, especially correct save support for HiROM and LoROM are corrected.

So, here it is: https://github.com/soniccd123/SNES-FeRAM-Cart

Some of the PCB features:
  • ROM Support for up to 4MB
  • HiROM and LoROM software (set by jumpers)
  • 32KB of FeRAM for saving (256kb)
  • No need for backup battery
  • Rudimentary ROM bank switch (Permits multiple games on same ROM)
  • SuperCIC support (still untested)
The github page contain all the Gerber files needed to produce the PCB as it is if one wants too. Also contains all the project in KiCad format for easy modification.

Be welcome to ask questions and make sugestions. I'm not a professional engineer and it may have flaws that i didn't noticed. Hope you enjoy and this helps someone!

Soniccd123

PS: I coudn't test the SuperCIC because I don't have any. It is connected to the cartridge port as instructed. If anyone build the PCB and test it, please share it.

calima
Posts: 1298
Joined: Tue Oct 06, 2015 10:16 am

Re: Open Hardware SNES Repro PCB with FeRAM support

Post by calima » Sat Nov 14, 2020 1:02 am

Is feram still as expensive as it used to be, many times the price of sram+battery?

soniccd123
Posts: 23
Joined: Sat Jun 27, 2020 12:01 pm

Re: Open Hardware SNES Repro PCB with FeRAM support

Post by soniccd123 » Sat Nov 14, 2020 11:39 am

calima wrote:
Sat Nov 14, 2020 1:02 am
Is feram still as expensive as it used to be, many times the price of sram+battery?
Well, i don't know if its as expensive as it used to be, I got the chips for like 8 dolars for 5 chips. It was a personal choice for me because I really have some bad experiences with batteries lol.

But this can be easily modified in the project if you need. Find a suitable SRAM chip and the battery management circuitry, i think theres even chips pin compatible with the FM1808 that I used (The 62256 is pin compatible i think). There is plenty space in the PCB for adding the needed components.

DeLFuS
Posts: 1
Joined: Tue Feb 23, 2021 1:33 pm

Re: Open Hardware SNES Repro PCB with FeRAM support

Post by DeLFuS » Tue Feb 23, 2021 1:40 pm

Hello!

I'm looking at your project and I find it very interesting. I have been looking for the FM1808 and have found 2 types FM1808B and the FM1808. Are both valid? or it has to be B. I have looked for the differences and I have found that model B is the substitute for normal and that the only difference is "Standby Current". Could you clarify this question for me, thank you. I have also seen that on your github they say that on your U5 pcb + 5v is not connected to pin 20. Is that so?

Thank you very much for your contribution to the retro community!

soniccd123
Posts: 23
Joined: Sat Jun 27, 2020 12:01 pm

Re: Open Hardware SNES Repro PCB with FeRAM support

Post by soniccd123 » Wed Feb 24, 2021 10:49 am

DeLFuS wrote:
Tue Feb 23, 2021 1:40 pm
Hello!

I'm looking at your project and I find it very interesting. I have been looking for the FM1808 and have found 2 types FM1808B and the FM1808. Are both valid? or it has to be B. I have looked for the differences and I have found that model B is the substitute for normal and that the only difference is "Standby Current". Could you clarify this question for me, thank you. I have also seen that on your github they say that on your U5 pcb + 5v is not connected to pin 20. Is that so?

Thank you very much for your contribution to the retro community!
Hey, thank you very much!

I haven't really tested the non-B version of the FM1808, but it should work fine

Thank you for pointing the not connected U5 pin 20, facepalm to myself for letting such a stupid error go unnoticed, after i've produced the last prototype before sharing the project, i've made some needed adjustments based on tests and must have deleted that trace accidentally. Hope anybody has tried to built it like this because, while easy to fix, would prevent the cart to work at all. I guess thats the spirit of open projects, everybody can give insights and point problems to fix!

Will update it with a fix as soon as i get to my computer

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