I have a Mega Drive Multicartridge that contains 40 Games and I wonder if there is some way to dump it (other than Retrode).
Multicarts have custom mappers so you are going to have to write your own dumping software if you go Mask Of Destiny's MCD cable route.
Stuff like retrode also need to be able to support such a mapper.
Least painful way I suppose is to desolder tho ROM and dump it with a EPROM burner.
Assuming that you've got a Megadrive flashcart, or some other means to run your own code on the console, you could try something akin to
TapeDump for the NES:
* Write a dumping program that you load into RAM on the Megadrive.
* After the program has been loaded into RAM; swap your flashcart for the cartridge you want to dump. (I've no idea if the Megadrive has some sort of mechanical switch to reset itself if you remove the cartridge. If it does maybe you can put something in place to disable that switch).
* Once the cart to dump has been plugged in, your dumping program can proceed with reading the cart's ROM contents and write them to the console's audio output as a PWM stream. Record this to an audio file on your computer and decode the audio to get the original bytes back.
Note that your multicart may have some extra circuitry for bankswitching and whatnot, which you'll have to take into account when you read its ROM contents.
ok but could retrode 2 dump that 40-games cart?
If anything, it'll dump the cart's init code, which you (or the manufacturer? I'm not familiar with Retrode's firmware development model) can use to develop a plug-in to dump the rest of the cart.
In any case, I've read somewhere that the official Genesis multis like 6-Pak route interrupts through a dispatcher routine that calls the correct handler for each game. As in Donkey Kong Classics and Super Mario All-Stars, no program banking hardware on the cartridge is used.
If there's no epoxy blobs on the multicart (but there probably is), then we can probably RE it from a photo of both sides of the PCB, too.
lidnariq wrote:
If there's no epoxy blobs on the multicart (but there probably is), then we can probably RE it from a photo of both sides of the PCB, too.
no there is an epoxy blob on it and I'm gonna upload the images now
here r the photos of both sides
The two non-epoxy blobs say "MC74F174N" and "SN74LS32N", correct?
If so, I'm using this reference:
http://wiki.megadrive.org/index.php?title=ConnectorsReads or writes to $A13000-$A130FF latch A1 through A5
The latch is cleared on reset.
The values latched from A1 through A4 are ORed with A17 through A20, and then sent to the actual ROM.
The value latched from A5 is simply sent to the ROM. (So this should be a 2MiWord ROM)
This feels very odd to me, but I'm not familiar at all with the 68k memory map.
lidnariq wrote:
The two non-epoxy blobs say "MC74F174N" and "SN74LS32N", correct?
If so, I'm using this reference:
http://wiki.megadrive.org/index.php?title=ConnectorsReads or writes to $A13000-$A130FF latch A1 through A5
The latch is cleared on reset.
The values latched from A1 through A4 are ORed with A17 through A20, and then sent to the actual ROM.
The value latched from A5 is simply sent to the ROM. (So this should be a 2MiWord ROM)
This feels very odd to me, but I'm not familiar at all with the 68k memory map.
could retrode dump it?
The Retrode should have no trouble reading the bottom half of it, without any modification. Dumping the top half requires driving the /TIME line (aka pad B31). I have no idea if the Retrode can do that; you should ask them.
With the information I gave you above, it's probably best if you take that information to the retrode forum and ask there.
Once you have a dump you will not be able ta play the ROM in emulation (not in all functionality) until some emulator author adds this mapper to their emulator.
However, you should be able to 'break apart' the multicart once dumped, and play most of the games separately. I don't know how they fit 40 games into 32 slots, though.
lidnariq wrote:
However, you should be able to 'break apart' the multicart once dumped, and play most of the games separately. I don't know how they fit 40 games into 32 slots, though.
I don't know how any particular Genesis game is laid out, but I know of several examples of multiple games filling a single PRG bank on the NES:
- Donkey Kong Classics
- Duck Hunt + Clay Shooting
- Balloon Fight + Balloon Trip
I had to make some myself for Action 53 in order to fit a menu plus 20 activities, one of which is fairly large, in the sixteen 32 KiB banks of the STREEMERZ bundle:
- Concentration Room + Russian Roulette + NES15
- Thwaite + Lawn Mower
- LAN Master + Munchie Attack
- MineShaft + ZapPing + Axe (toy) + Zapper Calibration (toy)
- Slappin' + FHBG
so if I dump it , I won't be able to play it with the emulator?
You might be able to reconstruct individual games to play, but you'd need to modify the emulator to support a multicart mapper, just as emulators needed modified for Super Street Fighter II and anything else over 32 Mbit.
Not as a multicart, unless you modify the emulator yourself. You should be able to take the 4MB dump and split it into a series of two 2MB, two 1MB, four 512KB, eight 256KB, and sixteen 128KB images, which hopefully will play as the individual games separately.
ok so how can I modify the emulator?taking into account that once I downloaded a multicart and some of its games didn't work.
ouso1999 wrote:
ok so how can I modify the emulator?taking into account that once I downloaded a multicart and some of its games didn't work.
The modification in question is probably more along the lines of adding additional functionality to the emulator. How to do this depends on which emulator, what language it's written in, how much you know about writing software, and whether or not the emulator in question has source available.