nesdev.org

Wanted to know if sfx2 is backwards compatible with sfx1. As in will a flashed sfx1 game work on a sfx2 donor board?


*Edit*
Someone also mention that lo roms can be loaded onto a high rom donor carts. It's how you burn the rom when programming or something like that. Also whats the difference with Slowrom and Fastrom as seen in http://nintendoallstars.w.interia.pl/ro ... eslist.zip?

Super FX games all use the same instruction set. If a game uses GSU-1, it will work on a GSU-2 board. Games that use the high speed mode (GSU-2 has it) may not work on GSU-1 or Mario Chip boards. Also, some Super FX boards have different amounts of RAM on board. So there is no clear yes or no answer. You'd have to be specific.

HiROM and LoROM mapping has nothing to do with how you burn the EPROM. It has to do with how the ROM is wired on the PCB to the Cartridge edge.

SlowROM requires a ROM (or EPROM) with a speed of 200ns or faster. FastROM requires a ROM with a speed of 120ns or faster.

MottZilla wrote:HiROM and LoROM mapping has nothing to do with how you burn the EPROM.

It does if you're running a LoROM program from an EPROM on a HiROM board.

Why would you do that? Wouldn't you be wasting a ton of ROM space?

If you've got a HiROM board and one EPROM and you want to load a LoROM game on to it, the waste would be to buy a LoROM board and make all the modifications, even though you could just load the LoROM game onto your HiROM game and "waste" space on the EPROM.

MottZilla wrote:Why would you do that? Wouldn't you be wasting a ton of ROM space?

In modern ICs, there comes a point where the packaging is far more expensive than the IC itself. At that point, there is little difference in cost between memory sizes, especially if a larger memory is already paid for.

Thanks for the reply MottZilla. Can we get a list of known ram sizes on games that use special chip sets. Mainly on dsp1/2, sfx1, sfx2, and sa-1 boards.

Well DSP1 games probably come with 2kbyte and 8kbyte ram chips, sometimes or maybe always battery backed. There are a fair number of dsp1 games and more than one version. DSP2 is used in 1 game. There is no other use for this board unless you develop your own game using it.

Super FX I think Doom has the most you can have which is 64kbytes. But I could be wrong. Doom also doesn't use a battery, and I don't think one could be added to it. Yoshi's Island, Star Fox, both have 32kbytes. Yoshi's Island is battery backed. Dirt Trax FX has 64kbytes. Stunt Race FX has 64kbytes + battery.

Kirby's Dreamland (sa-1) has 32kbytes. Kirby's Super Star (sa-1) has 8kbytes.

That's all I'll bother to list. To find out RAM on any game, load it in SNES9X and it will tell you imbedded ROM info when you load it up. ZSNES might too.

Will someone tell me what kind of sram carts use. As far as speed and sram type. There are a few different sram types listed here.

http://search.digikey.com/scripts/DkSea ... 980&k=sram

*Edit*

MottZilla wrote:Well DSP1 games probably come with 2kbyte and 8kbyte ram chips, sometimes or maybe always battery backed.

So with some dsp games there will be sram plus another ram ic on the board? what about sfx and sa-1. Will there be an sram + ram with either of these?

Cartridges will use your standard Parallel Static RAM chips with response times around what SNES MaskROMs were, so as fast as 120ns to no slower than 200ns.

No game will game SRAM and another form of RAM in it, that wouldn't have made much sense in costs. Again most SNES games contain a 8kbyte parallel static ram chip, probably with a 200ns response time or faster. Some games only have a 2kbyte chip. Few have a 32kbyte chip. I think 64kbytes is only found in Super FX games which would have the same type of chip but would be some kind of surface mounted version rather than DIP version.

I forgot the name of the game but there's this Japanese shmup authoring game with 1Mbit SRAM, although it's a regular cart. I think that's as big as it got for regular SNES titles.

edit: forgot to add that the manual (yeah I know) listed an SRAM bank select for SRAM, atleast that's what I remember. 128KB was apparently the max an SFX cart can hold. Wasn't used up obviously.

MottZilla wrote:Cartridges will use your standard Parallel Static RAM chips with response times around what SNES MaskROMs were, so as fast as 120ns to no slower than 200ns.

No game will game SRAM and another form of RAM in it, that wouldn't have made much sense in costs. Again most SNES games contain a 8kbyte parallel static ram chip, probably with a 200ns response time or faster. Some games only have a 2kbyte chip. Few have a 32kbyte chip. I think 64kbytes is only found in Super FX games which would have the same type of chip but would be some kind of surface mounted version rather than DIP version.

Although not used in retail cartridges, there are Super FX prototype pcbs with seperate save and work RAM:
http://dforce3000.de/?p=fdsingle&uid=95
http://dforce3000.de/?p=fdsingle&uid=161

The Super FX patent also mentions a DRAM controller, but I'm not sure if that was included in the mass-produced version.

Kirby's Dreamland (sa-1) has 32kbytes. Kirby's Super Star (sa-1) has 8kbytes.

Another SA-1 game, Pebble Beach no Hotou: New Tournament Edition, has 64Kbyte BW-RAM. 2Mbit are the theoretical maximum according to the official manual, in addition to the on-chip fast but tiny I-RAM.
Quite an interesting game with fully texture-mapped 3D-graphics. Hardly realtime, though. One single frame takes a couple of seconds to be rendered.

BW-RAM on the SA-1 is optional, both RAM types can hold savegame data (backup battery).

Apart from that, the BS-X host cartridge has 4Mbit PSRAM.