EPROMs & FlashROMs Question

[MottZilla]

I've been wondering a few things about EPROM and FlashROMs. Mainly does anyone know where you could find larger EP or Flash chips? I'm interested in 8M (1Mbyte) up to 32M (4Mbytes) chips but don't seem to see anywhere to buy such chips. More specifically I'm looking for 8-bit DIP type chips, although there are a few uses I would have for 16bit DIP chips.

So does anyone know where I could pickup some chips for a decent price? I'm looking into this before buying a new eprom programmer as the last one I bought was cheap and didn't work (it was a clone) and now I'm looking to buy a non-cheap one that should definitely work. But it's all pointless if I can't find the chips I want to put into cartridges and things.

[wildcat]

I would look in the yellow pages for a computer or electrionic whole sale in your area.

Make sure you have all the numbers on top of the chip or the chip with you, so they know weather they have it.

If they don't have the chip, just ask them were else you might get 1 cause they most likely will know if you can get it and were. Some times they have to order it in, that can take awhile, sometimes days or weeks.

[st!]

Sounds familiar... I couldn't find any flash chips in DIP package at that size, only eprom ones: 27C800, 27C160. However replacements like this (http://www.gotronik.pl/sklep/images/29f800/29F800_1.jpg) (TSOP48->DIP42) do fine for me. ;)

[Shogeki]

The good place to get cheap eproms is hk, there are really good deals right now on ebay:
http://myworld.ebay.com/ic-china/
That guy is really fast and he can even program the roms for cheap!
A 27C322 (32M), can go up to 40 bucks in the US, more than 20 in Japan, and only 2.5 bucks in HK ! (they have plenty of used eproms in singapore and hk).
If you are going to make snes games, some french team made some tsop --> dip adaptor to use flash roms (like 29F032) on the snes.

[wildcat]

Just out of question why do you say large? I thought from my experince there all 1 standard size? or at least basicly thats been my experince.

[Alchy]

Just out of question why do you say large? I thought from my experince there all 1 standard size? or at least basicly thats been my experince.He means capacity, but it's not like EEPROMs all come in the same size anyway.

[MottZilla]

Yes, capacity. The reason is that I don't want to make a SNES game that is 32mbit from wiring together 4 8mbit EPROMs and all that garbage. I'd prefer to cut traces on the board and rewire it for EPROM/FlashROM and have one chip.

Shogeki, thanks for the link. But I noticed the largest 8bit EPROM he has is 8Mbit. If I got a 32M 16bit EPROM, would I be able to wire up just the 8 data lines and ground or float the other 8 and essentially use it as a 8bit eprom? Also, do 32M 8bit eprom or flash even exist? Obviously I'm really hoping to find something I could solder directly to the board with some rewiring opposed to wiring between the board and the ROM.

Also, tell me more about this TSOP to DIP adapter for SNES. If it will fit in a cartridge with the DIP adapter soldered directly to the board that would be fantastic.

[wildcat]

Oh capacity,


My mistake! :rolleyes:

[Calpis]

If I got a 32M 16bit EPROM, would I be able to wire up just the 8 data lines and ground or float the other 8 and essentially use it as a 8bit eprom?
For 16M? Yeah you could but that's hella wasteful. You could instead use a couple MUX or buffers to get the full amount.


Also, do 32M 8bit eprom or flash even exist?
Yep, 27C320 are 8/16-bit but they're very rare. 32M 8/16 Flash shouldn't be very hard to find, the names just change with manufacturer.

[michal99]

You might know this, but if not there is nice article and cross reference about eproms and etc. http://www.mameworld.net/gurudumps/tutorials/how_to_dump/index.html

[Shogeki]

Yes, capacity. The reason is that I don't want to make a SNES game that is 32mbit from wiring together 4 8mbit EPROMs and all that garbage. I'd prefer to cut traces on the board and rewire it for EPROM/FlashROM and have one chip.

Shogeki, thanks for the link. But I noticed the largest 8bit EPROM he has is 8Mbit. If I got a 32M 16bit EPROM, would I be able to wire up just the 8 data lines and ground or float the other 8 and essentially use it as a 8bit eprom? Also, do 32M 8bit eprom or flash even exist? Obviously I'm really hoping to find something I could solder directly to the board with some rewiring opposed to wiring between the board and the ROM.

Also, tell me more about this TSOP to DIP adapter for SNES. If it will fit in a cartridge with the DIP adapter soldered directly to the board that would be fantastic.

Yeah apparently flash roms are the way to go.
Those guys scored some cheap one i guess (29f032, probably bought a lot of them to get a good price).
Everything is on this forum:
http://forum.ultimate-console.fr/

http://www.ultimate-console.fr/images/Divers/TSOP/DSC00463small.JPG

http://www.ultimate-console.fr/images/Divers/TSOP/DSC00463small.JPG

I was working on some of those for the neogeo, but eventually the price of eprom dropped. (tons of mvs bootlegs had those flash adapters in the late 90's release, i just copied some designs)
I7m wondering if you could just use a simple 27c322 and just rewire it, but if it would have been so easy i guess those guys wouldn't have gone through all that trouble.
They are working on a usb cart too, that can be really interested, especially for homebrews.

You can also use a simple adapter that you can find in any specialized shop :

http://ultimate-console.fr/images/Snes/DSC052412.JPG

http://ultimate-console.fr/images/Snes/DSC0526250.JPG

[grahf]

Hey Shogeki, thanks for the pics. Quick question, do you know any place local in Tokyo that sells flash roms?

-Ben

[Shogeki]

I know a place in akiba but it's too expensive (4000円 for a 29F016!), there must have some other place, i'm gonna look on the web.
The place i know has some adapters liek on the last pics and everything that has to do with eproms (but over priced in my opinion)
The best place to get some of those has to be china, but unlike eproms i can't find them on ebay.
I can ask my supplier if he can get me any, maye he can (the guy on the ebay link, he's got some 64mbit flash for pretty cheap).
Also do you know a good online electric component shop in japan ?

[grahf]

Not that i've found so far.. But I've only been hear a little over a year, so i'm still having
communication problems. There's digikey of course, but they are always so pricey.

I still have about six 27C801s back in the US when I was building Starfox carts, but I agree with them being too bulky 2MB+ games.

I really want to build some Gameboy flash carts, so i'm looking out for am29f032 or am29f080 at the moment. I picked up a GBC and have been on a Gamboy binge for a few months now :D

[Shogeki]

Oh ok, for parts i'm usually just ordering them off auctions sites, they have some good refurbished things. (and akiba also, thereare a couple of good cheap shops when i just need resistors/capacitors etc...)
I think I have some 28f008 in my den, but i've just mailed the guy for some 29c032, so i'll let you know.

[TmEE]

I can buy 64 and 32Mbit 8/16 bit flash chips locally BUT they are 5V intolerant :(


YAY, I can buy 32MBit 5V 8bit flash chips locally too... around 15$ a piece, in TSOP package though
http://www.elfaelektroonika.ee/cgi-bin/web_store.cgi?artnr=73-860-70#!73-860-84

I'll need 2 to create a 64M cart for MD...

[Shogeki]

I found some on the bay for 8 bucks a piece:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=360115429608

You will need some sort of adapter like that and then i guess there won't be any problems for using with the md (tsop 40 ---> dip40)

Something like that i guess:

http://img53.imageshack.us/img53/6250/tsopcz2.jpg

Btw are you making a some kind of flash cart or an it exist an actual megadrive game that is 64mbit ?

[TmEE]

I'm making a proto cart for the game I'm making... it is going to be a 64M game and my 32M proto cart is getting small for it :)

And seems it will be cheaper for me to buy those flash chips locally... 8$ for chip, 8$ for shipping... actually 8+8+12, but when I buy locally, I don't have to wait :)
And I need at least 90ns anyway, as I'd like to tinker with 32X also, and 90ns is quite on the edge for 32X.

I need to look for such TSOP adaptors... making a board for a TSOP by hand using not so great methods is PITA.

http://www.hot.ee/tmeeco/EEPROM/INACT2.JPG

[wildcat]

Thanks for those pic Shogeki,



Nice project, sound interesting,



Good Luck!:icon_bigg

[grahf]

Yeah, pretty cool. I've seen a lot of your projects on various boards, and they're always interesting to see.

[MottZilla]

So I'm a bit confused still, does anyone have a good place to get a DIP (even if through an adapter) for SNES that is 32Mbits and 8-bit? The French site I'm not sure will help much being that I don't speak that. If anyone knows though, do they sell you the adapter they designed? You don't have to make it? The other thing would be would I have to solder the memory onto the adapter myself then?

I really just haven't see any real alternative yet to buying 8mbit 8bit eproms and doing the mess to wire them all together.

Would whatever you have to do to use the 27C322 (16bit) with the 8bit configuration of the SNES be particularly difficult or expensive?

I could probably do the multiple 8mbit roms it's just that when you have a 32M game you can't seem to solder the roms all into the socket which seems annoying to me. Although I've heard some games actually have two ROM sockets in which case I guess you could do things a bit easier.

So really what are the options for 32mbit SNES carts? I'd like to build a few games which are almost all 32mbit.

[CaptainN]

Hi Mottzilla,

Did you find out anything on this? I also found out about the Tsop to DIP adapter the french guy designed. It's pretty neat! Do you know if they sell them? There are some detailed pictures of the adapter available on the french site, and some schematics (http://nintendoallstars.w.interia.pl/romlab/tsop2snes.htm) (http://nintendoallstars.w.interia.pl/romlab/tsop2snes.htm%29). Does anyone know where/how to order a couple of those pcbs, like from some Chinese manufacturer or something?

[Michael]

I'll have some 29f032 to dip to sell very soon from here in the US. I've got almost 50 made (with the flash soldered on), and I'm just kinda working out my setup to program and verify them. I assume I'm going to have to program them before I ship them out. I'll put something in the marketplace soon.

I actually started before I heard about the french guys (but of course we probably both stole the idea from nintendoallstars).

I don't have any extra pcb's. If I do another batch I could order extra pcbs.

[CaptainN]

Hi Michael,

Does your adapter have dip pins, or do you still have to connect wires from the SNES pcb to the pads on the adapter's pcb? If it has pins, can you just put the adapter into a programmer and program it as if it were an eprom?

And does it require any rewiring? I've been told the adapter of the french guy requires one wire. Did you make any changes to the schematics on the romlab website? Does it work with all SNES pcb's (lorom/hirom)?

I realize that I asked quite some questions, but I hope you're willing to answer them. :)

[Michael]

Yes, dip pins are soldered onto the board. Programming it isn't that simple, I'll provide more info soon. Really it depends on how your eprom programmer programs 29f032 (it's 40 pin, sometimes it's easier to see the tsop adapter for your programmer so you know what is needed to make an adapter for this if that makes sense). I personally feel this is a better solution for repros, not for a reprogrammable cart.

I don't remember if I made any changes to the schematics or not. If so, they were minor. lorom/hirom are the same pinout and don't matter (but without making changes, you don't get lorom/hirom off the same game circuit board). I think they only needed the extra wire for onboard programming .