Questions for those that know about doing SNES Rerpoduction games!

Hi there Assemblers! I have some questions regarding reproduction SNES game stuff.


I recently obtained a Repro of Dragon Quest I&II for the SNES, problem is for whatever reason, the person whom made it. Made it using the 1.1 Translation Patch for the game...which came out in 2002...INSTEAD of the 2.0 Translation patch that came out in 2003...(10 damn years ago!). (Which has some bug fixes and other changes http://superfamicom.org/translations/info/dragon-quest-1-2-english)


My questions are things like; Is it possible to re-flash the EPROM or whatever with the correct data? Or would you need an entirely new set of chips? Or would it depend on the chip itself?



Here are some pictures of the PCB (Or rather, sandwiched PCBs)
(I really dont' know much about this stuff)

Side Pictures showing the two separate PCBs stuck together via contact points
https://i.minus.com/id7b4Ee9pEXGZ.JPG
https://i.minus.com/icXUJ6u6PZL15.JPG

Close up of the chips on the 2nd PCB
https://i.minus.com/iqLuYBB6qSFux.JPG
https://i.minus.com/ib0Zl7FOlbC7Dn.JPG


Missing MaskROM?
https://i.minus.com/iPFDf6Z6vXM7D.JPG


Misc/side views:
https://i.minus.com/ig8EpuIpURrHu.JPG
https://i.minus.com/ijMRzJt4MBr2G.JPG
https://i.minus.com/iSnIvGv5AdZF7.JPG

Rear view of the 2nd PCB:
https://i.minus.com/izXXyNW4yuCh5.JPG


Front of the PCB:
https://i.minus.com/i9nOvAeADqytF.JPG

 

Yes, you could have the EPROM removed, erased, reprogrammed, and put back on the board no problem. Also the MaskROM isn't "missing", it was removed and this sub board was connected to the MaskROM socket. The sub board just makes everything *very* neat by having a circuit board to hookup some decoding ICs and a big 16bit EPROM without a mess of wires. In theory it should be quite sturdy and easy to reprogram the EPROM. Ofcourse, if you aren't experienced desoldering you might want to get someone that is to do it. And electronics, plumbing soldering doesn't help. =)

But besides desoldering and soldering you would need an eprom UV eraser as well as a suitable eprom programmer that can program a 27C322 eprom. These will run you around 100$ or so. Alternatively you could get someone to program a new eprom for you. However you will need to supply them the original chip so they know the byte order needed.

 

Ok thanks. I do have some experience with electronics soldering. But I don't have an Eraser or programmer (Nor enough knowledge to probably use them well) and by the original chip do you mean the original MaskROM from the donor board?


I don't have that, but judging by this
http://www.snescentral.com/pcbboards.php?chip=SHVC-1A3M-10

http://www.snescentral.com/pcb.php?id=0505&num=0&side=front
NBA Showdown / NBA Pro Basketball '94 - Bulls Vs Suns seems to be the donor board (only one with the same Hyundai SRAM chip)


If I wanted to have someone re-flash it who had the proper equipment,would I need to get a copy of the donor cart for it's MaskROM?

 

You misunderstand. The MaskROM of the original game was removed. The MaskROM contains the game program. MaskROMs are made in a factory and are non-programmable.

This cartridge you have had it's MaskROM removed. A new PCB was made that is connected to the Socket the MaskROM used to go into. On this new PCB is an EPROM, which is electrically programmable (but not erasable) as well as a few basic chips that provide decoding. Since you want to change/update the software on the cartridge, you need to remove the EPROM from the cartridge. It is the chip with the UV window. It is a standard 27C322 part. It contains the software that normally is stored on a MaskROM.

So again, all you need to do is replace the EPROM with one containing the updated translation, or to erase the eprom and reprogram it with the updated translation. The one thing you do need to know is the byte order of the eprom. The EPROM used is 16bit where as the SNES uses 8bit ROM memory. That's what the decoding chips are for. The reason it matters to you is so you program the file in the correct byte order so it works. You could just assume whatever the common default is though. Or you could get two chips, with one byteswapped and try both.

So anyway, you don't need to worry about maskroms or what game the board originally had. You're just trying to get an update put on it. So it's just a simple issue of removing the old eprom and erase/reprogram or replace with an already programmed eprom.

 

Ahhhh OK thanks for clearing that up.

Guess I just need to find someone who can burn this specific EPROM then, found a pair for a decent price on Ebay
http://www.ebay.com/itm/ST-M27C322-100F1-27C322-32MBIT-UV-EPROM-x-2PCS-/160702725462
(at least this is what I found when I put in the model number on the EPROM on my board)


Thanks for all the help and information. :=)

 

Or half the price here:

http://www.ebay.com/itm/251122516536?ru=http%3A%2F%2Fwww.ebay.com%2Fsch%2Fi.html%3F_from%3DR40%26_sacat%3D0%26_nkw%3D251122516536%26_rdc%3D1

 

Oh even better thanks! Now I just gotta find someone who could burn them I guess. (Well that and I need a new soldering Iron because the tip of my Solder gun is too big for SNES PCB work I think)

 

who made that repro? is very nice that method he use with the attached pcb to the mask.

 

I'm not sure. I got it off Ebay for ~30$ in an auction (Which is a steal for what Repros normally go for)


Here's the seller, he's got others and I'd assume he probably wasn't terribly pleased with the final price as the rest are BIN now.

And i'm not sure if he's the one who makes them or if he got them somewhere else and is trying to resale for profit(I'm thinking the latter considering the prices you'd pay for the same stuff from websites that make repros. But given the uniformity of the label designs and how they are consistently poor or incorrect in areas he may actually be the one making them)
http://www.ebay.com/sch/lazypedro/m.html?_nkw=&_armrs=1&_from=&_ipg=25&_trksid=p3692

 

<---- can burn pretty much any chip.

 

Which is great. Except shipping to the UK from the US seems to have gone up a lot recently. Though since they are small, it shouldn't cost Too much.

And I don't really have the money ATM ,since i'd also like to compensate for the help and I need a new soldering Iron,and some other stuff.


But now that I KNOW. I know who I can contact in the hopefully very near future!

 

Well, chips could be shipped directly to me.

for eproms (things that cant go letter - like thin chips can) would be £4-5 shipping

So in total, not much more than you were originally going to pay just for the chips.

 

That doesn't sound too bad. If you buy the auction and have it shipped to you and can burn them. I can pay you for the EPROMs(+Shipping to you) and the shipping to me.

and a little extra for the help.(wont' be too much I don't have a ton of money right now)

 

If you examine the add-on PCB, the byte order could be figured out so you could only need 1 correctly programmed eprom rather than having both byteswapped and not byteswapped EPROMs programmed and just trying each one and seeing which works.

The MaskROM A0 pin is involved in deciding which 74*257 outputs. And which one outputs and what Data lines on the 27C322 are connected will tell you the byte order.

I only see the MaskROM Socket, 27C322, and the two 257s on the pcb's bottom size. It's possible the top side has a surface mount chip. Bad_Ad84 can figure it out I'm sure.

 

You would hope its big endian, as its supposed to be using 8 bit chips and you could program it directly without byte swapping.

Is this saying to order them now? or are you planning to do it in the future and PM me?

 

You can do it now. I've got enough money ATM for this. I can Paypal you the money for the chips to be sent to you now. And when you ship it out to me, I can do the rest(Won't know the shipping cost to me until it's sent right?) PM me your Paypal address

I thought about PMing you before but I thought you'd reply eventually hah sorry.



Also:

Would taking a picture at a different angle of the addon board help you determine this? Or is it part of the board that is hidden underneath the original PCB?

 

You'll have to ask Bad_Ad, he knows how his programmer is setup. I've never had to program 16bit chips myself. But when sending files off to get programmed for Genesis I found that they needed to be byteswapped. This may or may not be the case with the SNES board you have. If you can see where A0 goes, it should go to a 74*139 I think.

If the 139 is connected like this you can figure if it's big or little endian.
1. SNES /OE
2. SNES A0
3. SNES /CE
4. Some pin of one 257 chip
5. Same pin but of the other 257 chip.

This is actually for the use of 245s, im not sure if 257s is the same. But the point is A0 determines which of those chips puts data on the bus, and by which data lines they connect to on the 27c322, you know if the first byte of the rom file should be D0-D7, or D8-D15. I would imagine no swapping is needed, but that would be if the endian setting on the programmer is correct too. The easiest thing is just trial and error. Get two chips, one with the data programmed normally, and the other byteswapped/opposite endian. Try using the normal one first, if it works great. Erase the other one sometime and use it for something else. If it doesn't, try the second, if it works, the first one can be recycled later. If neither work then you need to check your soldering job.

 

Thanks i'll keep that in mind!

 

Damn! any way we could get a picture of the board attached to the SNES PCB desoldered from front and back? I would love to copy the design and use it for my own repos, plus these chips are cheap right now.

 

£3.09 for the chips to me
£4 for shipping to you (its crazy that the Chinese can sell the item AND ship it for less than my shipping costs)

I have bought them, so PM me for my paypal details and to give me your address.