Dumping for fun

carlsson · Post by **carlsson** » Fri Mar 31, 2006 9:09 am

If the cartridge autostarts, at least block 5 is used. Whether any more block is used can be hard to determine without:

1) Opening it and check the chips
or 2) Dump the first 8K block, then try to load it back and execute

If the computer freezes, it could be a sign part of the program is missing, and then you should dump blocks 3 or 1 as well. Up to now, I don't know of a single 16K cartridge that uses blocks 2 and 5.

Mayhem · Post by **Mayhem** » Fri Mar 31, 2006 2:01 pm

Now with the board I have, with the cart plugged in, if the "block 5" switch is in "5" position and not "normal" then the cart doesn't boot. This is how I can load the dumper program and get something out.

Do you think if I also had the "block 3" toggling, I could peek some memory to tell if something has been loaded into that block when the switch is in "3" position?

I had a look at Funet, and found Tank Wars there. Strange that Dirk had not taken it for the v1 of GB20. Guess I will have to check the other files there to see what others might be missing.

carlsson · Post by **carlsson** » Fri Mar 31, 2006 2:08 pm

Aha. I would suppose a cartridge always overrules the onboard RAM, so you don't even need a block 3 switch? In that case, a bit of POKEing and PEEKing could help you:

* If PEEK to an address returns the previously POKEd value for any value used, it should be RAM that shines through.
* If the PEEK returns random values, no memory at all is connected
* If the PEEK returns a different, but consistent value, it should probably be ROM.