Eprom sizes and Boards Types

goldendark007goldendark007
in Help Wanted!
As previously discussed, a 512kb eprom (such as the AM27C512) can be used on an NROM-256 board but only the first 256kb will be used.

I am curious if AM27C040 (the small eproms I have on me at the moment) can be used on a PNROM (MMC2) and SKROM (MMC1) board. According to NESdev wiki they are capped at 128kb. I am just curious if this works the same as what was discussed before.



Thanks!

 

Comments

  • goldendark007goldendark007
    bump
  • LincolnLincoln
    you can use the 512 chip but can only make use of 256k. it's a straight drop in.
  • MrPete1985MrPete1985
    A 512 chip should work but the NES will only be able to access 256k like Lincoln said. I would connect the highest address line to GND to always force the chip into the lower half.
  • goldendark007goldendark007
    I don't care so much about that. It's for Iwata Edition Balloon Fight so I don't need to access past that anyway.. correct?
  • GuntzGuntz
    Yes.
  • GuntzGuntz

    Originally posted by: goldendark007



    So I have used the 12MB board to make Star Ocean... and the 6MB board to Chrono Trigger:Crimson Echoes and Tales of Phantasia.. any other good suggestions for games to throw on these or is this all they're really good for?



    Thanks!



    Dragon Quest III English translation.
  • goldendark007goldendark007
    I've been meaning to check out dq3. Any others?
  • GuntzGuntz
    Not that I know of. I guess there's that oversized re-translation for Chrono Trigger but that's about it.
  • goldendark007goldendark007
    bump
  • LincolnLincoln
    dude stop changing your threads, you're deleting stuff that might help someone in the future. just make a new thread.
  • goldendark007goldendark007
    Originally posted by: Lincoln



    dude stop changing your threads, you're deleting stuff that might help someone in the future. just make a new thread.





    Very sorry. Just thought I was doing a favor recycling as not to create clutter. Will keep in mind for the future.
  • LincolnLincoln
    Originally posted by: goldendark007

     
    Originally posted by: Lincoln



    dude stop changing your threads, you're deleting stuff that might help someone in the future. just make a new thread.





    Very sorry. Just thought I was doing a favor recycling as not to create clutter. Will keep in mind for the future.





    no worries dude. if you have another question in the same vein just add it on. if it's entirely different then make a new thread.
  • goldendark007goldendark007
    Ok fixed it to include both topics - I will make new topics for new discussions from now on. Thanks
  • goldendark007goldendark007
    bermpf
  • LincolnLincoln
    You can always use an oversize chip, but you might be limited in how much of it is accessible. For skrom you can access 256K by default due to the way the mapper is wired on the board. MMC2 can only do 128K so that's the most you can use on a PNROM board without some crazy hardware hack.
  • goldendark007goldendark007
    So it's safe to assume I can always use a larger chip but only the first (whatever the capacity of the board is)K will only be accessible? So I can put a 128K PRG (copied 3 times and combined into a 512K PRG) onto a 512K and it'll be fine? Thanks Lincoln
  • LincolnLincoln
    yep
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