Jump to content
ralphb

Flash ROM Cart

Recommended Posts

Oh, now I see. Yes, you need either jumper of resistor -- otherwise, the signal is missing from the bank switching circuit!

Share this post


Link to post
Share on other sites

That resistor normally just keeps the cartridge reset circuit from being a dead short when cartridges are inserted into the console. It is such a low value to ensure it doesn't do much to interfere with the signal, but if it isn't present, you would need the shorting wire across the pads to ensure the reset circuit actually forces a reset.

Share this post


Link to post
Share on other sites
Jim, that's true for the connection between RESET and -5V, but this resistor has a different purpose.


It's used for bank switching, and dates back to Atarisoft cartridges. You can read all about it in this earlier post: http://atariage.com/forums/topic/250540-flash-rom-cart/?p=3549738


Back then there was an issue with incorrectly wired capacitor and resistor. Besides the incorrect wiring, it also turned out that modern components are so fast that the FlashROM doesn't need resistor or capacitor. But since you need to have something connecting the signal in the cart port to the 377 doing the switching, I just said keep the resistor.


EDIT: clarification

Edited by ralphb
  • Like 1

Share this post


Link to post
Share on other sites

If you don't want to build one, is the FinalGROM99 from the Brewing Academy the one way to go or are their other options?

 

My FinalGROM 99 is the successor to the FlashROM 99. The FinalGROM runs ROM, GROM and mixed ROM/GROM cartridges, and features 1 MB of RAM for images, among other improvements. You can get it from me via email, from Arcadeshopper (who sells my carts), or various other sellers offering clones of unknown quality throughout the web.

 

The demo you saw could only handle single-bank GROM images, at least at the time.

 

If you don't need an SD card for supplying images, there's also the very capable UberGROM (also at Arcadeshopper).

  • Like 1

Share this post


Link to post
Share on other sites

its too bad that a small part of that SDcard in FG99 can't be used as scratchpad to perm storage. As in allowing the minimemory to actually be emulated. As the way MM works in FG99 it loses memory stored on power down.

Share this post


Link to post
Share on other sites

its too bad that a small part of that SDcard in FG99 can't be used as scratchpad to perm storage. As in allowing the minimemory to actually be emulated. As the way MM works in FG99 it loses memory stored on power down.

Actually it can, using a modified MiniMemory binary, with an additional menu entry to save the contents back to the SD card.

  • Like 2

Share this post


Link to post
Share on other sites

ill try the .bin again, i did try a version yesterday and had no luck. maybe it was an old .bin..thank you very much for this change! it only makes sense and if i knew more i would have done something similar!! again, thanks sir.

Share this post


Link to post
Share on other sites

ill try the .bin again, i did try a version yesterday and had no luck. maybe it was an old .bin..

 

There was some discussion a while ago about the FinalGROM overwriting some bytes in the RAM area when writing back to the SD card. The solution was first to change the addresses of those bytes, but later it occurred to me that I just needed to read those bytes first.

 

To be honest, I'll have to recheck which version I'm shipping now with the FinalGROM. I may also have to re-create the Minimem image.

 

BTW, this thread is for the older FlashROM. For the FinalGROM, see here.

Share this post


Link to post
Share on other sites

its cool. BTW i put tape diwn that reset line and its still resetting on me..i looked at that layout showing pins..i went ahead and tried covering both sides of pin 1, like 1 and 2 anyway..but naaa..its gotta be me or maybe the tape is sliding...hmm maybe try whiteout...

Edited by GDMike

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...