Retro replacement carts

Hello all,

Ok, just by reading the topic you'll think "why post something like that in the development section?"

Simple: I'd like to know how many people would be interested in a device that lets you play Atari/NES/SNES/Genesis/GB/etc. on the original respective console?

I was thinking about making that kind of device, but not sure if it's worth the time vs. the amount of people who would use it

Greets,

Pit

P.S.: Please don't reply if you're going to suggest using an emulator

 

I enjoy gaming on the original console, so hardware that would let me move a ROM image to an actual cart would be neat to play with. However, past attempts to produce and to sell this sort of gear have always been priced outside of my comfort zone. That's perfectly understandable, as it's necessary not only to make a cartridge edge with working contacts, but also some sort of software to manage moving bits onto the (erasable) ROM.

Based on your description, I'm guessing that you're looking at making some sort of universal cart that fits into multiple consoles with adapters? That could cut your asking price some, but it would also mean using a more expensive chip. On the other hand, if your expertise is more on the software side, then you might be able to get away with using removable storage, like Compact Flash or something else IDE based.

 

Those exist since ages ago, and are still manufactured. Many HK enterprises do make them. Unless you give some good prices, expect to fail.

 

Can you give me some info on them? Which companies?

 

yes, I would like to know that too.

 

http://www.tototek.com/

 

tbh, I thought about using usb as an interface to write to nand flash or sd card...
making my own filesystem and all, but the loader would have to be done by someone else

and yes, it would just need an adapter

 

Most retro consoles just have an ROM soldered withouth any else circuitry, you would just have to plug an SRAM to the console bus and dump on that SRAM the NAND / SD card contents, then switch on the SRAM so the console reads it.

Some consoles (NES / Famicom and Neo Geo AES / MVS), are very difficult to replicate. NES does have many different types of cartridge mappers, Neo Geo has some crazy amounts of ROM (from 40 to 718 megabits), so you would need to reverse engineer all the mappers, or put some HUGE ammounts of SRAM / DRAM for storing the game contents.

Of course, you'll have to RE some carts for getting the bankswitching system used in them, how does SRAM work, or how does the protection system work (NES, Neo Geo, SNES...).

Of course I assume that you have some pretty damn good knowledges of electronics, console reverse engineering, programming in descripting languages, etc...

Cheers and good luck. I asure you, if you made a AES flash cart you'll get a lot sold. The problem is the price, actually.

 

I'm sure NES and similar won't be too hard to do, but AES flash cart? Isn't that what was cracked only recently?

 

On the contrary, NES is a real pain thanks to all it's custom mappers and the fact that 5V FPGAs seems to be getting rare (according to people that know more about this stuff then me) also NES, SNES and N64 also have the lockout chip.. thought the NES lockout chip have now been cracked (took a couple of years )

 

Pit: I don't think you realize how elaborate these cartridges are. For practically all consoles there's more to it than just emulation of a ROM. Even if the consoles were just ROM, NAND flash in practically all instances just isn't fast enough to emulate ROM for these consoles, especially SD cards which use a serial interface! You need intermediate storage such as RAM.

8-bit Atari: emulation of 1x 8-bit 1Mbit? ROM, 1x 8-bit 256Kbit? SRAM, CPLD for emulation of multiple memory mappers, to support all you'll need FPGA since there are a few which are logically huge.

Atari Jag: emulation of 32-bit 32Mbit ROM and small serial EEPROM.

FC/NES: emulation of 2x 8-bit 4Mbit ROM, 256Kbit 8-bit battery backed SRAM, mapper emulation (requiring FPGA) You will have to design logical clones of at least 30 mappers, some of them are just TTL chips, others are full blown LSI. You'll need to use Kevin Horton's CIC clone, or salvage them from carts (you'll get sued), or crack your own or add an additional cart connector to use a legit cart's CIC.

MKIII/SMS: emulation of 1x 8-bit 4Mbit ROM, 64Kbit? 8-bit battery backed SRAM, 2x mapper emulation configurations (requiring CPLD)

PCE: emulation of 1x 8-bit 8Mbit ROM for normal games, emulation of 20Mbit ROM + mapper for Street Fighter (requiring a handful of TTL or CPLD)

MD/GEN: emulation of 1x 16-bit 32Mbit ROM for all games, emulation of 40Mbit + mapper for Street Fighter, 8-bit 256Kbit battery backed SRAM. SRAM mapping can be done with TTL or CPLD. For RAM decoding multiple ways a CPLD is required.

GB: emulation of 1x 8-bit 32Mbit ROM, 8-bit 256Kbit battery backed SRAM, mapper emulation. There are ~5 popular mappers to emulate, large CPLD for emulation of most functions, FPGA for full emulation of all mappers.

SFC/SNES: emulation of 1x 8-bit 32Mbit ROM for most games, 48M for all normal games, 8-bit 1Mbit battery backed SRAM for all normal games, For RAM/ROM decoding, and address shifting multiple ways a CPLD is required. CIC chip hasn't been cracked yet so you'll need to salvage chips off carts (you'll get sued) or crack it or add an additional cart connector to use a legit cart's CIC...

N64: emulation of 1x 16-bit 512Mbit ROM, 1x 256Kbit 8-bit? SRAM, 1x 16Kbit serial EEPROM, 1x 1Mbit Flash ROM, CPLD required for latching/demultiplexing the address bus + address counter. CIC hasn't been cracked yet so you'll need to salvage chips off carts or add an additional cart connector to use a legit cart's CIC or crack them or use boot emulator (you'll need to get permission from authors or they'll be mad)

Neo Geo AES: emulation of 2x 8-bit 8Mbit ROM, 1x 16-bit 128Mbit ROM, 1x 16-bit 256Mbit ROM, 1x 32-bit 512Mbit ROM, CPLD required for multiple character bankswitching schemes, CPLD required for multiple program bankswitching schemes, CPLD/FPGA required for decryption (optional, games can be cracked beforehand), TTL/CPLD required for audio ROM latching, TTL/CPLD required for character ROM latching, CPLD required for character ROM multiplexing chip emulation (you will have to RE this big 64-pin package since nobody has released info on it.)

 

Pit? Where are you? o.o

 

http://www.weilei.com.cn/vp180E.htm

alot of carts can be hacked to take an eprom already, but for those that can't you need to reverse engineer the cartridge and then someone like this to make you a load.

http://www.pcbexpress.com/

you then fill in the rest of the components.

Or you can sometimes pick up the official developer cartridges, which often used eproms/flash chips.

 

ahhhhh sorry

what I meant was, only the cartridge itself, nothing more
that is, for instance, I won't use battery backed-up srams, but will just store them on nand flash
it will really just be something that converts parallel flash to nand flash...
nothing more

oh, and a programmer for it of course!

 

So you are talking about putting a flash inside a cartridge, and connect it to an adapter for inserting them into consoles. Sincerely, that's a pretty stupid idea.

I think that using a SD card would be way more efficient, even with it being serial. Put the BIOS on a EPROM, load the BIOS on the console RAM, let the user select the game, load the SD game to the cart RAM, use the RAM as if it was ROM.

 

flash, sd card, cf, whatever it's all the same, only different interfaces

All I (have to) care about is how the cartridge looks to the console...
Which is a memory space...it reads and writes in that memory space...
The cartridges use eeproms and sram along with asics to choose where exactly to write (sram for saves, asic for bank switching) or read (eeprom)
Here we just give it a specific address space and that's it
really simple idea...start + offset0 = eeprom; start + offset1 = sram; start + offset2 = bank switching (which will be done by internal logic to switch banks)

 

Buddy, it's NOT really simple, how do you think you'll translate ROM access into NAND access in ~100ns, much less for multiple 8-32-bit buses?!

And what will you do to RECONFIGURE the logic for different bankswitching methods?

I'm not convinced you've really thought this out, please reread all the requirements in my previous post.

 

I still say that you should read the contents of the flash / SD / FTP server, whatever, and dump them onto a common SRAM, being it connected to the actual console bus with all the ciruitry required. Not directly passing data from the NAND to the console.

 

SRAM is not a good option for the 16-bit consoles, SRAM costs ~$8/512KiB and the largest chips you can find are 512KiB. For Neo Geo that would only cost $1200-1400 inside 177 SRAM chips

You can get enough DRAM modules Neo Geo for like $10, and ~$20 of SRAM.

 

Oh well, I didn't know how the prices / sizes did go, DRAM then.