xkeeper

welcome to my personal hell

dragon warrior iii for the game boy color describes me as "stubborn", and i'm tempted to agree with that assessment


co-owner tcrf.net. i run an old forum, jul.
i've been around the internet since '01.
i generally feel like the internet
peaked somewhere around '07.


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18+: @xkeeper-TI


plural / some kind of digital therian thing.
still discovering myself.
all of this is new to me.


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steelfoot
@steelfoot asked:

Hey, I'm part of a small team of people working on making a fully-functional copy of Robopon Star (US) from the unreleased ROM and a donor cart. I have EEPROM selection questions (in particular the usual EEPROM generally used for GB repros is too small and I'm trying to find a viable substitute) and am looking for someone who knows or has done this sort of thing. Know anybody who might be able to help?

i would not know where to begin, unfortunately; you have as much knowledge as i do regarding physical repro carts. (maybe a little more.)

maybe someone who does know more will comment or something? but i don't think i can be of much help beyond that.


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in reply to @xkeeper's post:

I am indeed starting with another Robopon cart as the donor. I wanted to make sure that all the functions are intact for preservation reasons, which is why I never even considered a standard-issue repro cart (though I did look at their boards to know what chips were generally used). Mercifully, the boards and ICs appear to be otherwise identical between the JP and EN revisions, so the cheaper JP board is being used instead of the $75 US Sun cartridge.

My biggest issue right now is getting ahold of a suitable EEPROM. Because Robopon is a huge ROM at 1MB in size, the common 512k EEPROMs used in most repros I've found are simply too small. (The large filesize, along with the person I've spoken with who is working on decompiling Sun stating that he believes it was compiled from C just from how clunky the code feels, is probably why it's so damned slow.) 32-pin, 1MB TSOP EEPROMs running at 5V seem to be weirdly uncommon, for some reason, so I've been shopping for alternatives.

Due to my lack of experience and rudimentary knowledge, I'm uncertain if the exact number of pins and exact size of EEPROM are completely necessary, or if I can go bigger. My assumption is that the code will just ignore the extra pins and use what it's "used to," and extra addresses will never get referenced so it's fine, but I'd really like to ask someone who knows before I go dump money on another batch of chips that won't work. (I already did on some that were advertised as 1MB but were actually 1Mbit. rip)

The code is definitely compiled from something higher level. I worked on the HuC-3 reversing so I'm well aware of how janky it is internally. I think it's some sort of high-level runtime that's completely unsuited to the GB which is why it runs so slow.

I do know how to work with additional pins on something like this, so I'd probably be able to figure it out from the pinout in documentation.

Cool. I would love to read about what's going on in that funny little thing, even if I would only be able to understand about half of it.

As for the datasheets, the chip on my US Robopon board (which I took apart to check) is an MX23C8006. I haven't been able to find one with the 6 at the end, but https://pdf.datasheetcatalog.com/datasheet/macronix/MX23C8000MC-10.pdf seems to be just about the same thing? As for the EEPROM, my current best match looks like this one: https://www.microchip.com/en-us/product/AT27C080

Hey, thanks. I don't really have the reach or know where to start looking for people, so I really appreciate the boost. c: I really hope I can get this thing together; I got Sun as a kid and spent years looking for Star only to find out that it was never released, then the whole thing where the ROM was found happened, and now I wanna see how it behaves in its "natural" environment and get it to communicate with Sun.