Horun wrote on 2024-01-25, 03:15:

Good job ! Glad you got some that work. May sound strange but can you post a picture of them ? you do not need remove them, just a general close up be ok, am curious of the chip layout.

Oh certainly! Attached are front and back pictures (from the eBay listing).

Btw Im not so sure about the parity being at all important here. Id wager a guess its ignored completely and parity output is not even connected to anything on the motherboard.

That is entirely possible, I did not uninstall the board and traced the pins...
Having said that, looking at the different modules schematics, the only difference between these modules and the other modules that don't work is that the ones that don't work use these quad cas chips for parity, as far as I can tell.

Thanks for the pictures ! Their layout is different than mine and the datasheet, but am not surprised 😀

I am trying to source yet another kind of modules, with a different layout, will report on those too...

Jollyroger wrote on 2024-01-25, 01:26:

I am very pleased to confirm that it works! The THM362020ASG-70 are doing the trick, I have a full complement of 32MB now 😀

Good thing I mentioned these what you need to look for helped so much for you.

That's happy ending.

Cheers,

Jollyroger, I have also a Sophia dev. Kit and mine came with 4 SIMMs. My question ( which look stupid) is what is the purpose of this additional ram to this dev kit ? I know that you can play Sega Saturn games without all of them, so what is the intention to have them all installed?

debugging

rasz_pl wrote on 2024-10-10, 05:11:

debugging

Debugging, any idea how ? Does the Sophia need the E7000
Or any other tools to use it .

Since this is a dev kit its main purpose is debugging. No clue about this particular model software package.

When the Sophia was introduced, the Hitachi E7000 ICE and its software package was the preferred method of tracing/debugging software for the Saturn.
Eventually these were superseded by the CartDev system and its own software package, which can work either with the specially modified Cross Saturn console, or with a Sophia programming box.

And yes, the purpose of the SIMM modules was to provide extra memory for debugging purposes. One could load/store in there data that could be accessed at runtime beyond the stock capabilities of the Saturn console. It's very common for development kits to have more RAM than the stock console units for that reason. The Sophia could host up to 32MB, which was a huge amount for the time.
Maybe this was also a way to enable development for the ST-V system that used ROMs instead of the CD drive.

Too bad that the SIMM modules don’t act like an expansion ram memory for games. My Sophia can’t boot games that require ram expansion ( 1 or 4mb), so i hoped to find a way to use the SIMM to boot them… unfortunately it doesn’t. I also tried the Saroo but it doesn’t work and i can’t boot anything with it. I also tried to change the bios ( 1.003 original to a 1.01) but then I had not picture.

Fun fact : king of fighters 95 with its ROM cartridge works fine on my Sophia.