Some recent discussion about official Nintendo test cartridges reminded me of one that doesn't seem to be discussed as often, the SNSP "Aging Cassette". It's basically an earlier Japanese version of the "burn-in test" from a couple of the other test carts (and get a load of that totally non-copyright-infringing background music!)
In addition to the normal test routine that runs on a loop when you fire up the cartridge, there's also an additional routine at CPU address $00B0D6 that does not seem to actually be called anywhere. Running it displays this screen:
which runs infinitely and reads some hardware measurements using registers at $21C0-1, $21C8-9, and $21CB-D. The text shown in this screen doesn't occur in any other test ROMs that I have.
Could there be some way to access this screen normally (i.e. without patching ROM) that I'm just somehow not able to find? Is this something from yet another test cartridge that I don't have / isn't dumped? Is anything known about the specific hardware that this screen uses to perform the measurements? I couldn't really find any info online about this particular cartridge, aside from the fact that it exists.
In addition to the normal test routine that runs on a loop when you fire up the cartridge, there's also an additional routine at CPU address $00B0D6 that does not seem to actually be called anywhere. Running it displays this screen:
which runs infinitely and reads some hardware measurements using registers at $21C0-1, $21C8-9, and $21CB-D. The text shown in this screen doesn't occur in any other test ROMs that I have.
Could there be some way to access this screen normally (i.e. without patching ROM) that I'm just somehow not able to find? Is this something from yet another test cartridge that I don't have / isn't dumped? Is anything known about the specific hardware that this screen uses to perform the measurements? I couldn't really find any info online about this particular cartridge, aside from the fact that it exists.