Re: [stella] Dumping ROM images

Subject: Re: [stella] Dumping ROM images
From: "Eckhard Stolberg" <Eckhard_Stolberg@xxxxxx>
Date: Sat, 12 Mar 2005 09:05:13 -0500
>I say to keep things simple.  Several years ago I made a cart reader from a
> 555, three 7LS161's and a 7400 NAND gate chip.  I connected this to the
> parallel port of a PC and wrote some code using QBASIC, hey it was what I
> had.  The 555 was set up as a one shot and was reset from one of the 
> signal
> lines from the PC port, this was how I synced the PC to the cart reader.
> Using this I ws able to dump the ROMs for Sir Lancelot and Moon Sweeper. 
> At
> the time the ROM image floating around for Moon Sweeper was only 4K, it is 
> a
> 8K game and some folks were looking for Sir Lancelot.  I can't remember 
> the
> details, I will have to check my old PC to see if the program is still on
> it.  It was nothing fancy but it worked.

Unfortunately that's a bit too simple for bankswitched games.
With this method you would always access all bankswitching
hotspots in a row. So the data after the hotspot addresses will
always be read from the last bank. In fact we had to add a special
bankswitching mode to z26, because people kept complaining about
these two ROMs. ;-) The games couldn't be started in the first bank,
because the system vectors were read from the second bank. So we
had to add a special bankswitching mode for these two F8 games
were the game gets started in the second bank.


Ciao, Eckhard Stolberg


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