Open Hardware SNES Repro PCB with FeRAM support

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Kayumba
Posts: 246
Joined: Sun Mar 01, 2020 2:36 am

Re: Open Hardware SNES Repro PCB with FeRAM support

Post by Kayumba »

lidnariq wrote: Wed May 26, 2021 3:51 pm Note that memories with "V" in the part number are 3.3V devices: they will be damaged by being operated at 5V, and will damage 5V parts if they are operated at 3.3V without voltage translation.
Thank you, it's good to know about "V" indication.
Yes, dont worry, I will use voltage translation.
soniccd123
Posts: 46
Joined: Sat Jun 27, 2020 12:01 pm

Re: Open Hardware SNES Repro PCB with FeRAM support

Post by soniccd123 »

Kayumba wrote: Wed May 26, 2021 2:55 pm Hi soniccd123,

I would like to use 1024 Kbit FRAM like FM28V100 or CY62128EV30LL vs 256Kbit.
FM18W08 : pin 1 (A14) and pin 26 (A13) have different connections for LoROM and HiROM.
pin 1 :
LoROM cart 39 = A14
HiROM cart 42 = A17

pin 26 :
LoRom cart 38 = A13
HiROM cart 41 = A16

Should I do the same with 1024 Kbit FRAM for A13 and A14 address pins ?
Thank you
Yeah, thats correct, but if you want the SNES to see all the 1024Kbits of the FRAM, the mapper need to be updated to address the rest of the chip address space. As almost no games use more than 256Kbit, I supose that you want to create some bank switching scheme for multcarts right? If thats the case, then connecting A13 and A14 as you said will work.
Markfrizb
Posts: 607
Joined: Sun Dec 02, 2012 8:17 am
Location: East Texas

Re: Open Hardware SNES Repro PCB with FeRAM support

Post by Markfrizb »

As almost no games use more than 256Kbit, I supose that you want to create some bank switching scheme for multcarts right? If thats the case, then connecting A13 and A14 as you said will work.
There’s only 1 game that uses more than 256k sram, at least on the standard non-special chip carts.
http://snescentral.com/pcbboards.php?chip=SHVC-1A7M-01
I forget the name at the moment though.
poorstudenthobbyist
Posts: 252
Joined: Fri Jun 24, 2016 4:20 pm

Re: Open Hardware SNES Repro PCB with FeRAM support

Post by poorstudenthobbyist »

I believe it was Dezaemon 2.
Kayumba
Posts: 246
Joined: Sun Mar 01, 2020 2:36 am

Re: Open Hardware SNES Repro PCB with FeRAM support

Post by Kayumba »

soniccd123 wrote: Wed May 26, 2021 5:21 pm
Yeah, thats correct, but if you want the SNES to see all the 1024Kbits of the FRAM, the mapper need to be updated to address the rest of the chip address space. As almost no games use more than 256Kbit, I supose that you want to create some bank switching scheme for multcarts right? If thats the case, then connecting A13 and A14 as you said will work.
Yes it’s for Multirom rom.
First I will do Multirom by reset, then maybe once I will learn how to do Multirom with menu selection.

And yes, I know that There is only one game (with no special chip) that need 1024kbits, Dezaemon 2.
That will be sad if that my PCB wouldn't accept this one 😊
soniccd123 wrote: Wed May 26, 2021 5:21 pm the mapper need to be updated to address the rest of the chip address space.
What do you mean ?
Do you mean chip mapper ‘139 decoder ?
Can you explain me please.

Or do you mean that :
If I will use 1024Kbit chip and will use pin 1 (A14) and pin 26 (A13) to alternate between LoROM and HiROM, like that SNES will see only 256Kbit size.
Is that right ?
Zauberlolly
Posts: 1
Joined: Sat Dec 18, 2021 12:39 pm

Re: Open Hardware SNES Repro PCB with FeRAM support

Post by Zauberlolly »

Hello Guys,

Can anyone please post a picture of the Front and Backside from a finished pcb? I want to see the correct chip orientation. Thank you.

Best Regards Zauberlolly
Kayumba
Posts: 246
Joined: Sun Mar 01, 2020 2:36 am

Re: Open Hardware SNES Repro PCB with FeRAM support

Post by Kayumba »

Hi Sonic,
I see that you dont use "multiplexers" like 74HC257.
74HC245 is an octal transceiver.
Are they here to convert from 16bit to 8 bit?
arquino
Posts: 2
Joined: Thu Aug 18, 2022 6:44 am

Re: Open Hardware SNES Repro PCB with FeRAM support

Post by arquino »

Hi guys, I'm having the same problem mentioned above. Games just have a black screen.
I didn't find anything related to byteswap for 27c322. Can you explain to me how I do this byteswap process?
Markfrizb
Posts: 607
Joined: Sun Dec 02, 2012 8:17 am
Location: East Texas

Re: Open Hardware SNES Repro PCB with FeRAM support

Post by Markfrizb »

I recently purchased this pcb and I wanted to share a few things about it. Now, in all fairness, I make and sell SNES repo pcbs but I wanted to comment on SonicCD123's design, share my observations and recommendations, parts links, all of which is contained in this pdf linked.
OpenSource Snes w Fram.pdf
(189.05 KiB) Downloaded 124 times
I have not read all 4 pages of comments and questions so if all this has been addressed before, sorry for the duplication. Maybe this will be helpful for some looking to take on this project. I'll post some pictures in the near future.

Edit: pictures of chip orientations. Arrows show pin 1
31452F44-28E6-414B-93A7-982F5E1AEC5E.jpeg
71B28E78-97CC-41C8-B3E2-90DB80655342.jpeg
Also I did a video review:
https://youtu.be/5dJqAjGZy20
vadymvatsenko
Posts: 1
Joined: Fri Jun 23, 2023 11:20 am

Re: Open Hardware SNES Repro PCB with FeRAM support

Post by vadymvatsenko »

soniccd123 wrote: Wed May 26, 2021 5:21 pm
Kayumba wrote: Wed May 26, 2021 2:55 pm Hi soniccd123,

I would like to use 1024 Kbit FRAM like FM28V100 or CY62128EV30LL vs 256Kbit.
FM18W08 : pin 1 (A14) and pin 26 (A13) have different connections for LoROM and HiROM.
pin 1 :
LoROM cart 39 = A14
HiROM cart 42 = A17

pin 26 :
LoRom cart 38 = A13
HiROM cart 41 = A16

Should I do the same with 1024 Kbit FRAM for A13 and A14 address pins ?
Thank you
Yeah, thats correct, but if you want the SNES to see all the 1024Kbits of the FRAM, the mapper need to be updated to address the rest of the chip address space. As almost no games use more than 256Kbit, I supose that you want to create some bank switching scheme for multcarts right? If thats the case, then connecting A13 and A14 as you said will work.
Hi, soniccd123, have you tried testing Aladdin? My game hangs. Are there any nuances?
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