EPROMS in Battle Kid carts

[98digger]

Hello, NESDEV.

I have recently ordered the original "Battle Kid: Fortress of Peril" homebrew for the NES. I was viewing pictures of the cart online and noticed that the PRG ROM chip is what appears to be an EPROM.

I am no fan of the EPROM chips, as they erase themselves over time.

So, my question here is to anyone who has recently purchased this cart: Do they still contain this type of chip?

I have noticed that the newer Battle Kid 2 contains no windowed chips, so I am suspecting that RetroZone in now using one-time burnable ROMs instead.

Also, what memory management controller do the Battle Kid games use?

Thanks!

[tepples]

What chips are on the Battle Kid board, other than the ROM, RAM, and CIClone? If you're uncertain of what mapper you're seeing, that might help you understand what's going on under the hood.

[Jeroen]

As I understand it, OTP chips nowadays are just UV erasable roms without the window. They will still suffer from bitrot over (a long) time.

The good news is that you can just overwrite any eprom with the data thats supposed to be on there to "refresh" it, that is if it has suffered from bitrot. Don't even have to erase it.

[lidnariq]

I am no fan of the EPROM chips, as they erase themselves over time.
So, my question here is to anyone who has recently purchased this cart: Do they still contain this type of chip?
I have noticed that the newer Battle Kid 2 contains no windowed chips, so I am suspecting that RetroZone in now using one-time burnable ROMs instead.

The newer ones use EEPROMs (possibly Flash variant) instead of UVEPROMs. Both have a lifetime somewhere between 20 to 100 years. Both have comparable total reprogramming cycles. The only difference between them is one of them is less tedious to reprogram later.

The set-up cost for a Mask ROM (as you are implying you want) is sufficiently large it's apparently not even close to economically feasible until you're ordering ICs in quantities of millions.

[Bregalad]

The set-up cost for a Mask ROM (as you are implying you want) is sufficiently large it's apparently not even close to economically feasible until you're ordering ICs in quantities of millions.

Only the very best games sells millions of copies. I don't know the market, but inserting "tousands" instead of millions in your sentence would probably make it correct. The situation evolved since the '80s though.

[98digger]

What chips are on the Battle Kid board, other than the ROM, RAM, and CIClone? If you're uncertain of what mapper you're seeing, that might help you understand what's going on under the hood.

Whoops, it looks like I mixed up the MMC with the Mapper.

I don't know for certain, but I think that either an MMC exists on the cart's pcb or it is somehow built into one of the chips. It is quite a large game, so it looks like some sort of MMC is behind it.

Also, the EPROM in the official stock picture of the cart has no sticker or tape over it. Could that potentially be dangerous to the cart?

[tepples]

I don't know for certain, but I think that either an MMC exists on the cart's pcb or it is somehow built into one of the chips.

Again, you sound unsure, and you're being unspecific. Tell me what chips are on the board, and I'll help you understand where the mapper is.

It is quite a large game, so it looks like some sort of MMC is behind it.

Consider another "Battle" game. Battletoads doesn't have an MMC, VRC, FME, or any other ASIC mapper, yet it's a large game. Instead, it has a couple tiny unassuming 7400 series integrated circuits that act as the mapper. A "discrete" mapper built out of 7400 ICs is unable to provide quite as many services as an ASIC, but in some games, those services are unnecessary. This way, the manufacturer is unburdened with the higher cost of an ASIC.

[lidnariq]

Only the very best games sells millions of copies. I don't know the market, but inserting "thousands" instead of millions in your sentence would probably make it correct. The situation evolved since the '80s though.

That's my point (the anymore bit). Most ROM manufactureres don't even manufacture mask ROMs anymore. It's just not worth it unless they're all spinning up a mask for an entirely new silicon die for other functionality (e.g. microcontroller, northbridge, whatever) and even then, most manufacturers have taken to preferred programmable memory to be able to fix things in case something is broken. Nintendo may well be the last company to have had short-ish runs of bare mask roms, in DS cartridges (although I remember someone insinuating they might have programmable too)—everyone else wanted some kind of cryptographic lock with it, or wanted reprogrammability, or had quantities of millions.

Also, the EPROM in the official stock picture of the cart has no sticker or tape over it. Could that potentially be dangerous to the cart?

Yeah, that's bad. Put metal foil tape or at least electrical tape over it, if it arrives uncovered. I bet it won't, though.

[98digger]

I'll be sure to let you all know the specifics of the Battle Kid cart when it arrives.

Until then, I have found a picture on Screwattack of Battle Kid 2's prototype:

http://www.screwattack.com/news/battle- ... orking-now

I do know at the moment that all of the Homebrew games available on RetroZone use the "ReproPak" PCB, which supports a large amount of mappers.

I have also noticed that, judging by their stock pictures, RetroZone uses EPROMS in nearly every Homebrew game they sell.

Yeah, that's bad. Put metal foil tape or at least electrical tape over it, if it arrives uncovered. I bet it won't, though.

Unfortunately, every Battle Kid cart I have seen on the internet has an exposed EPROM window. I will, however, put electrical tape over it once it arrives. I just hope it doesn't void the 60 day warranty.

[lidnariq]

Keep it in a dark box when you're not playing it, and wait for the 60 days to pass, and then cover the window. The bits basically only erode on exposure to UV; 60 days in indoor lighting away from windows will be fine.

[MottZilla]

It takes a pretty long time to erase an EPROM without a proper eraser. You might be worried if the EPROM was programmed a long time ago, but a recently programmed one isn't going to be erased unless you make a habit of leaving it out.

I don't think I've seen any Battle Kid cartridge pictures that show the use of an UV EPROM. Even if they did, the colored cartridge case will provide some protection and if you store it in the black dust sleeve that is common it will be just fine. But I think most if not all Battle Kid cartridges (excluding bootlegs) probably use EEPROMs.

[98digger]

I don't think I've seen any Battle Kid cartridge pictures that show the use of an UV EPROM. Even if they did, the colored cartridge case will provide some protection and if you store it in the black dust sleeve that is common it will be just fine. But I think most if not all Battle Kid cartridges (excluding bootlegs) probably use EEPROMs.

On this site, there is a picture of the cart. Although difficult to see, There is a circular shape on the PRG-ROM, which I believe is an EPROM window.
http://chipmusic.org/forums/topic/1093/ ... ed/page/2/

Also, I think I may be getting a little too paranoid about it , but I found this article:
http://my.ais.net/~xtreme/SF/Bit-Rot/

So, I have been wondering, has the technology behind these EPROM chips improved since 1980/1990, so that they are less likely to erase over time?

[lidnariq]

UVEPROMs have gotten better, and even matured before both types of EEPROMs.

That said, you're really overestimating the rot rate: we're talking about decades for even the first 'PROMs with proper protection, and centuries now.

I can dig up 30-year-old UVEPROM datasheets that specify 20-30 year retention times, and 15-year old ones that specify 150-250 years.
For EEPROMs, those numbers are closer to 15 years old and 8 years old.

[tokumaru]

I do know at the moment that all of the Homebrew games available on RetroZone use the "ReproPak" PCB, which supports a large amount of mappers.

tepples has been insisting you say what ICs are on the board so he can tell you what the mapper is, but if you look around you'll see that this question has been answered a long time ago, and tepples has been hinting at the answer you first asked! =)

[98digger]

UVEPROMs have gotten better, and even matured before both types of EEPROMs.

That said, you're really overestimating the rot rate: we're talking about decades for even the first 'PROMs with proper protection, and centuries now.

I can dig up 30-year-old UVEPROM datasheets that specify 20-30 year retention times, and 15-year old ones that specify 150-250 years.
For EEPROMs, those numbers are closer to 15 years old and 8 years old.

I am hoping the cart contains UVEPROMS rather than EEPROMS, now that you have mentioned this. And judging by the pictures on the net, I would say they definately do contain UVEPROMS!

tepples has been insisting you say what ICs are on the board so he can tell you what the mapper is, but if you look around you'll see that this question has been answered a long time ago, and tepples has been hinting at the answer you first asked! =)

Thanks for bringing up that post! So it looks like the game is a UNROM cart.