I'm wondering if this issue has to do with the padding. The Checksum I get for CRC32 is 0x4c3edb9c After padding it to 4mb I don't understand where to find the hashsum in Ucon64. The part I'm confused on is during the padding step. I actually tried it on a second donor board but that didn't work either. I double checked my work, tested continuity on everything but no dice. I tried using the SA-1 Origin version but couldn't get it to work. Unlikely but possible.ĭanexmurder wrote:I've tried to do this mod using the Shining Scorpion Donor PCB but haven't had any luck. Merely another working hypothesis.Ī faulty SRAM chip could at this point still be the cause for your PGA European Tour board, if patched Gradius III utilizes more SRAM at the beginning than the former (which should be a good bet: PGA European Tour uses an 8 kByte / 64 kBit chip, and I believe the SA-1 patches transfer quite a lot of stuff into BW-RAM at the beginning), and if only some higher addresses / cells of the chip return garbage data. But maybe differences in CIC signal processing behavior correlate with differences in patch compatibility. your and Arthrimus' findings (all other things being equal, an official ROM worked while a patched one didn't) results that a difference in CIC signal processing did not cause the failure. What was actually going on was/is probably that there are multiple versions of the SA-1 chip, and more games than just SMRPG affected by that variance – but there’s no way of knowing which is which by looking at it. But there’s no way of knowing which is which by looking at the cart" (see here). This reminded me of the old observation that "there are meant to be 2 versions of available, one will work on an PAL SNES with the lockout chip disabled, the other won’t. It was brought to my attention that with SA-1 games, it's different: some exemplars of the SA-1 chip check for the presence of a CIC signal of the correct region (if it's absent or of the wrong region, they refuse to work), while others, apparently, aren't bothered about the lack of a signal and only refuse to work if they detect a signal of the wrong region. Just as a note: the old-school way of making (a good share of) games from one region work on a console from the other region, was to disable the console's CIC by lifting pin 4 of the CIC. But I think chances are good that much could be learned already without this nontrivial and time-consuming procedure. The endgame would be an eventual decapsulation, imaging and analysis of the die, as has been done and is striven after regarding other chips, ideally different variants so that they can be compared. Perhaps the smaller but also affected SA-1 speed test ROM could be a good starting point. So the next step would perhaps be to logic-analyze the SA-1 pins to get an idea of what happens after the SNES system is powered on, which, given the existence of different SA-1 variants, would also have its own merits with regards to emulation accuracy / preservation. Obviously, the patches do something that official ROMs don't, but comparing the code introduced by the patches with the code of official SA-1 ROMs may be like looking for a needle in a haystack, the cause may be timing-related et cetera. Indications are that officially released ROMs that make use of the SA-1 work with all SA-1 chips. But what's more important is that the patches can be improved to work with all of them, so that one wouldn't have to worry about this anymore. It's inconvenient if one intends to build a conversion and fishes out a non-working exemplar. While sample size was small, a change in the package coinciding with a change in circuit design, in turn leading to some nuanced changes in behavior, would have been plausible. On the plus side all this soldering practice has really helped improve my soldering skills, which was one of my main aims of this project, so that's a win! But this has definitely got me very confused. The last thing I can try is swapping the RAM off the working Japanese version and seeing if that changes things, as maybe it's a faulty RAM chip. So the ROM chips are both working fine on the Japanese build, the SA-1 is working fine but both dot and chamfer behave the same, and the game runs fine with the original ROM chip of PGA European tour on it. Removed the RAM and inspected the pads, but everything looks fine. Put the ROM chip off the PAL version onto the Japanese version and this runs fine. Swapped the ROM for the working Japanese version of Gradius, and this had the exact same booting issue, stuck on the white boxes Passed this test as the game booted and ran fine Swapped the ROM for the original PGA ROM to confirm SA-1 was working OK. Same boot crash issue where it only shows the white boxes I replaced the SA-1 chip with a chamfered edge one. I have done quite a few bits to try and get the PAL version to work, but to no avail.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |