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billywo · Joined: 08 May 2009 Posts: 14

I've just got my hands on a Super Wildcard DX2 which I need for a development project on the SNES. I need a SWC DX2 as it allows a DSP pass-through which is essential for my work.

My project is to create a Super Mario Kart semi-sequel which will be playable on the console rather than an emulator. Now, I'm at the stage through my project where I'm happy with the progress using an emulator and I want to start developing on the target platform.

I found this:
http://www.algonet.se/~sledge/swc/SWCDX2FAQ.pdf

This doc explains that Super Mario Kart is compatible with the SWC and has been tested by the author.

I don't have any DSP version compatibility issues as I'm using the original cart as the pass-through.

Now here's the problem. The SWC seems to operate fine. It plays all the original SNES games I have from the above pass-through slot, internal memory & floppy disk. However, when I make an attempt to play Super Mario Kart (the only 1 game that I actually need it to work with) - it doesn't work properly. The game initially appears to be fine until you get into a race. Once the MODE 7 graphics start rotating around the screen, I get a graphical corruption when the player moves around.

I can guess that this may be a DSP problem since this is the co-processor that deals with the scaled & rotated sprites (ie the track surface). All the other graphics/sprites are fine.

Now - is there anyone out there that has a SWC that can test Super Mario Kart on their setup for me? I need to establish if the SWC is broken or if the claims that SMK work on a SWC are false.

Any help on this would be greatly appreciated.

Tanooki · Joined: 11 Jul 2008 Posts: 73

Mario Kart works perfectly on my DX2...

madman · Joined: 07 Jul 2006 Posts: 598

Have you tried using a different SNES? I have seen some later SNES consoles not play well with the SWC DX2. On some it flat out will not even bring up the menu, I've never heard of the problem you describe but it's something to try. But DSP pass-thru is definitely a feature on the DX2 so it should work fine. You should even be able to run SFX games from the cart slot on a DX2.

xiaNaix · Joined: 10 Apr 2009 Posts: 67

Are you using a power supply with the SWC or is it being powered by the SNES? Some consoles cannot supply enough power to the copier and graphical corruption will occur.

billywo · Joined: 08 May 2009 Posts: 14

xiaNaix · Joined: 10 Apr 2009 Posts: 67

I've heard that a Genesis power supply will work with it. I use one of the dual power supplies that had adapters for both SNES and Genesis. 9VDC 1000mA center negative.

amptor · Joined: 14 Nov 2003 Posts: 207

You shouldn't need to worry about the polarity of the power supply. I opened two SWC DX's and they both have a device inside that switches the polarity over to what the unit needs to run. So if you plug it in backwards, it won't fry the unit. It will just work.

I'm not sure how much current these require. I have a 800mah one and plugged it in my DX and it really makes no difference at all to the operation of the unit. I think I pawned my genesis 1 adapter on ebay since I had no use for it after I sold my GDSF7. I think one faq states that you should use 900mah for the SWC DX2. I plugged in a 12V 2.0A power adapter (core positive, mind you) the other day to mine and saw no difference whatsoever in the function of the unit.

madman · Joined: 07 Jul 2006 Posts: 598

Well if your swc dx already works without the power adapter, what kind of difference did you expect with one plugged in Very Happy

Silver · Joined: 21 Dec 2006 Posts: 34

I don't think power is the issue here - you would see similar problems on other games, unless the fx chip in the mario cart is drawing extra power. Any other fx chip games to test?

I've seen similar issues from dirty contacts - check the cart, the dx2 (both sets) and snes itself. All this kit is now decades old, and can get either dirty or slightly 'loose' (i.e. pushed out of position). The DSP games like mario kart use more pins than standard snes games (extra ones at the ends of the cart slots) which is why it can be fine on normal games...

You can clean with any isopropanal cleaner, and use a small screwdriver to bend contacts back.

The only other issue I can think of is timing. Games which use chips in the cart (any game with special chips - e.g. mario kart) are passing data timing critical data to/from a CPU in the cart - much longer traces than on Snes PCB. Going through (any) copier really increases the trace length so the signals take longer to get to/from the extra cpu. I've had games in the distant past that worked fine on one copier and not on another (both supporting passthrough).

billywo · Joined: 08 May 2009 Posts: 14

Thanks to all who have responded. All advice is noted.

I haven't managed to get my hands on a power supply yet but I'm working on it!

I'll give all cartridge slots a decent clean as soon as I'm out of work tonight and try again.

I studied the corruption yesterday and found it to have a pattern. If you imagine a top view of the course your playing, the corruption only occurs when you are facing North, West, South & East EXACTLY. Any in-between angles you have the kart & the graphics are perfectly fine. Very odd! Confused

I'll post again when I've explored all possibilities you've all suggested. Thanks again. Smile

SpooNMan · Joined: 31 Oct 2007 Posts: 89

I can verify Super Mario Kart and several other DSP carts work fine in the slot of my SWC DX (32MB). I use SMK to play other DSP games.

I've never needed an external power supply with my copiers (SWC, SWC DX, SMC, PFX).

I would clean the cart contacts with a pencil eraser and try some canned air and/or Nintendo system cleaner on the SNES and SWC (make sure not to spray an icy blast though!)

sledge · Joined: 20 Jul 2009 Posts: 27

So you found the information on my site? Great to hear that it's still interest in the DX2. I haven't been using the DX2 for quite some time now, but I do think I have the same problem with my unit together with Mario Kart. I can't remember, so I have to try it out. Will be back with info...

amptor · Joined: 14 Nov 2003 Posts: 207

Maybe try a different copy of Super Mario Kart in your unit. I used to borrow one from a friend in high school and it'd glitch out and put me off course and I'd have to be carried back onto the track. I have a "Made in Mexico" version of Super Mario Kart which I bought brand new so I know where it has been and it works perfectly fine.

MottZilla · Joined: 08 Sep 2004 Posts: 765

If you cartridge is dirty it can result in crashes, corrupt graphics, and in the case of Mario Kart all sorts of wackyness if the response or interaction with the DSP chip inside it is suffering from a bad connection.

Cleaning your cartridges, is important. Even more so if you've ever rented cartridges or bought cartridges that have been rented out. If you have a cartridge that hasn't been handled as much you may get away without cleaning it.

Also Mario Kart does not use the extra pin connections of the SNES at all. The DSP1 chip doesn't use those connections. Cx4, SA-1, SDD1, OBC1, SFX, and some others do, but DSP1 doesn't.

One more note, you definitely should clean any games with important save data on them. If your cartridge is dirty it's not that hard for the game to corrupt your save data and you'll lose it. I've lost save data before because of a dirty cartridge. Not a very nice experience.

Mystic_Merlin · Joined: 15 Oct 2007 Posts: 496 Location: Bangkok

Also another thing I noticed recently, it seems the PAL version of SMK does not work properly on a SFC, I get all sorts of glitches/freeze.