NES -> SNES 'converter'?

[spinal]

I have seen a few r0mz on the internet which seem to be fully working NES games converted to work on a SNES.

AS - Mario Bro (NES Hack).smc

"_6@DDD@D@D@DDD@D@D@DDD" [Bad checks
um] LoROM, Corrupt, ROM, NTSC, SRAM:
Corrupt, ID:----, CRC32:5D59BBC6

They work OK in SNES9x and I tried a couple on the SNES Myth, they didn't work, although they are NTSC and I have a PAL SNES (and carts of course) I assumed that to be the problem.

Anyway, having read a few websites about the SNES, a lot of people seem to agree than the SNES should be backwards compatible with the NES yet Nintendo did nothing with that.

Does anyone know how these games were converted to run on the SNES and would it help in anyway to creating a NES emulator/converter for the SNES Myth?

[mic_]

The 65816 has an emulation mode which is compatible with the 6502. A lot of work would have to be done to patch memory accesses to certain areas, convert graphics data, and (especially) sound data/code.
For more details you should probably ask tomaitheous over at the nesdev forum, since he has ported a few NES games to the TurboGrafx (also a 6502:ish-based console), or Memblers who wrote an NSF player for the SNES.

[the|Gamer]

Hi,
well because Nintendo planed Compatibility for NES Games on the SNES there is a NES Mode in the PPU but I dont know how to activate it!

[mic_]

on the SNES there is a NES Mode in the PPU

Do you have a credible source to back that claim up with? I know that both 2-bpp and 4-bpp layers are available on the SNES PPU, but I've never heard of it having something like the NES's attribute tables for example.

[Dr.neo]

we are trying to make one HW to let SNES play nes/fc cart on it 

[mugenmidget]

we are trying to make one HW to let SNES play nes/fc cart on it 

AWESOME!!! 

[Conle]

we are trying to make one HW to let SNES play nes/fc cart on it 

Awesome news!
 

With 128Mb PSRAM + this new addition i think that no other flashcart out there could be compared with SNES/SFC myth.

 

[~tak]

sounds like a new tri-star/super 8 adapter?

 

[mic_]

Are you planning to use one of those NES-on-a-chip circuits and route the audio/video output to the SNES like the Super Gameboy does? If that's the case, I hope you're aware of the compability issues (I've never heard of a NoC that can play Castlevania III properly for example, and the audio is usually inaccurate for many games).

[Dr.neo]

Are you planning to use one of those NES-on-a-chip circuits and route the audio/video output to the SNES like the Super Gameboy does? If that's the case, I hope you're aware of the compability issues (I've never heard of a NoC that can play Castlevania III properly for example, and the audio is usually inaccurate for many games).

hehe you are right, but not 100%, our new adaptor can play Castlevania III perfectly, and support world-wide region very well, you can choose the region on your TV screen.

and, sound is not the issue with it.

[mic_]

That sounds great. Does it support expansion audio like MMC5, VRC7 and N106? What about FDS games?

[amptor]

There was a program to convert NES to SNES made over 10 years ago but it was very, very limited what it could do.  It could only process a handful of games and, after converting, they lacked sound.  And yes Anthrox converted a few more but those also lacked sound and in place of the sound as far as I recall they put their own music.  It had been discussed for years among sceners and yes they said that the SNES could emulate the NES but progress was never made on that beyond those few addon carts that were made which you still couldn't dump the NES cart from.  If Dr Neo is coming up with something to make this work on the neo snes myth cart, that is pretty cool though.  That would be a first for any copier that exists.

Also trying to copy your own ROM into the files that are already available is futile since they are all encoded from multiple files and a proprietary source code per game conversion.  All of this has been tried many times in the past when people found the tool or the anthrox games.