How big a deal is this really: 3.3V Flash in Retro Consoles?

[Rick Dangerous]

Someone posted this article in a status update the other day and i've been thinkging about it quite a bit:

 

https://db-electronics.ca/2017/07/05/the-dangers-of-3-3v-flash-in-retro-consoles/

 

I have Everdrives for nearly all my cart based systems. I have the cheap Chinese multi carts.

 

Am I actually frying my systems slowly, or is this alarmist?

 

I've invested a lot in getting rare and sought after consoles, and modding them to perfection, so it would be a real pain to fry something and then need to replace it....

 

What is your take? I am certainly alarmed after reading this article. I've never had any problems personally, either with the cheap multi-carts, which work perfectly on my AV modded top loader, or any of my everdrives.

[phoenixdownita]

Dunno, see what Krikzz has to say wrt the EDs:

http://krikzz.com/forum/index.php?topic=6614.0

 

 

My opinion is that level shifters are the way to go BUT a simple resistor and how his flash cart works would already limit the potential for issues anyway so much so I am not loosing any sleep over it.

 

The worst carts in the EDs series according to that article have to be from the old series: MasterED v1, TBED v1, MegaED v1

[v2s have level shifters either everywhere or just excluding the databus which during gameplay is only used in read mode which means it's the 3V3 flash/PSRAM chip putting data on the 5V databus and that is perfectly safe, during flashing/writing Krikzz revealed that he lets the FPGA drive the databus as a speedup technique so once more it should be all safe as the FPGA is a 3V3 component, not sure if this last part is true for all the carts old included]

 

The issue with that article is the usage of an explosion as opening image and some alarmist tones without actual bench measurements .... I contacted the author via FB and he stated that once he has some more time he will capture the address bus and data bus with a scope to see how bad it really gets ... and that is really what I would like to see (I'm expecting very short overvoltages spike around 1/10 to 1/20 of his estimates to be fair but that's just speculation on my part)

Let's not forget that the way the article tackle the issue is from the point of view of feeding a constant 5V to all pins of a 3V3 flash chips which is not what happens in reality, not even close.

 

I don't think anyone (Krikzz included) defends the old design per se, just lowering the tones wrt the alarmistic nature of what's been said.

 

Here I say it: even using a couple of diodes to lower the voltage rail (some of the cheap multi do that) is acceptable as long as those diodes can dissipate the extra power .... say you need to drop 1.4V and you find 2 diodes each of 0.7V drop, if the chip ends up consuming a constant 20mA, each diode needs to be able to dissipate 20mA * 0.7V = 14mW which is really nothing:

https://www.fairchildsemi.com/datasheets/1N/1N914.pdf

that there can dissipate 500mW and conduct 200mA .... so even those chinese knockoff carts that use series diodes to lower the power rail are not as bad as depicted wrt that aspect mind you they still need resistors on the address pins to limit current/drop voltage ... but the point stands, he was attacking the usage of the series diode itself ... it's not ideal for sure but it's not that evil either (at 10+mA also that diode I linked the spec for would drop 1V dissipating then 20mW so a series of 2 would be feeding the chip just 3V and that is well within specs).

To be clear wrt cheap chinese knockoff, the series diode on the power rail is NOT the issue there.

 

In short wrt EDs you are NOT putting a nuke into your beloved old clunker.

 

NOTE: we all are assuming that the only ESD protection is by the 2 input diodes, reading around it turns out that that was the most basic old design to protect the delicate CMOS metal gate and companies have stepped up their game quite a bit by using 2 or 3 levels of ESD protection .... which means the diodes are not the only protection at play most likely ... that was because as geometry shrunk damage caused by ESD still during fabrication process was impacting the yield. I don't know if the specific flash used by the EDs is "well-protected" or not as the datasheet says very little about it but I suspect it fares way better than we seem to think.

[Tanooki]

It's alarmist and real, what he said there above: "My opinion is that level shifters are the way to go BUT a simple resistor and how his flash cart works would already limit the potential for issues anyway so much so I am not loosing any sleep over it." just below that krikzz link that explains things.

 

There's a smattering of a chance his stuff may cause a problem long term, but it's not shoddily built like chinese garbage multicarts and kits. I won't be using my 161in1 on my MVS anymore out of paranoia, but the super everdrive v2 I feel confident with.

[Austin]

The worst carts in the EDs series according to that article have to be from the old series: MasterED v1, TBED v1, MegaED v1

 

I've got a MegaED v1 and have used it consistently for six to seven years now. I'd say if there was really a problem, I most likely would have experienced it by now. Still, it's interesting to think about. The article is certainly alarmist.

[phoenixdownita]

Krikzz has run more tests and shown the results (MasterED v1 and TB ED v1) and as expected the results are much much tamer than the article predicts (you can find the actual video links towards the end of his forum thread)

 

The point stays the same, the article albeit not incorrect wrt the mismatch between 5V and 3V3 discounts too quickly the actual ESD protections of the chips (which we can only guess) the actual duty cycle of the bus (it's not a constant 5V), the protection provided by even just 100ohm and in the end it should have at least done some measurements.

 

With a scope we likely would see some of the predicted overvoltages spikes, just not spiked enough or long enough to make the big difference he seems to imply.

 

Wrt the 161-in-1 only the address buses [NG having more than one ] signals could have issues (the data coming from the chips is again read out so the databus don't really have any bearings). If the address buses go directly to the chip then there's mismatch if instead they go thru the FPGA once more it takes the brunt but the chips are then fine. I am not suggesting to anyone to use/not-use just stating that even in that case reality maybe somewhere in the middle .... they are not high quality, no doubt about that at the same time without them I would never had the pleasure to experience the NG on the cheap (granted I have an AES and use the 161-in-1 via MagicKey so maybe there's another level of intercept and possibly a chance to "match the voltages" ... or not .... I can't recall if the MagicKey uses level shifters anywhere or simply tolerant components)

[Tanooki]

Maybe the NeoGeo instance is more unique.

 

Taken word for word from the NeoSD FAQ as the very bottom covers the shady 161in1 and others like it: "161 in 1 has no logic level buffering - 3.3v logic levels go straight to the Neo Geo chipset, this is BAD for the Neo Geo. NeoSD uses logic level buffering to protect Neo Geo boards and the NeoSD itself."

 

This isn't a good thing, it doesn't have the ability to fight the way that cart sets itself up and it can kill the hardware.

[Rick Dangerous]

Thanks guys awesome inputs... I think I am going to just keep using my Everdrives and SD carts with confidence.

 

Think I will have to leave the NES 500 in 1 cart on the shelf for a while and not buy any more of those......the old, if it seems too good to be true it probably is scenario.

[keepdreamin]

Some will freak out, that's a given. I'll keep using my mega everdrive until it dies, but that doesn't discount the points the author is making.

Like he said in the article, just because you've been smoking for two months and haven't gotten cancer, doesn't mean smoking doesn't lead to cancer.

 

My view on all this is a follows. When you're paying a premium for an Everdrive (or similar), you're taking it on good faith the expensive product you're buying has been properly designed. Which means the creator is observing all datasheet specs provided by the component suppliers.

"I tossed some resistors in there, and all seems ok" isn't going to cut it, sorry. If I wanted to take a shot in the dark and cheap out, I'd buy something off aliexpress.

 

The smart thing, and really only choice for Krikzz moving forward is to make the necessary design changes to be within manufacturer guidelines. There's nothing to argue against.

[Osgeld]

"161 in 1 has no logic level buffering - 3.3v logic levels go straight to the Neo Geo chipset, this is BAD for the Neo Geo. NeoSD uses logic level buffering to protect Neo Geo boards and the NeoSD itself."

 

 

This is exactly ass backwards from the real problem, hence smart hobby people != proper engineer, kind of like the author of the article having a hissy fit about ground planes, yes they are good, cept when they are not

 

jimbob's whacky cart emulator I doubt it makes one lick of difference

Edited July 12, 2017 by Osgeld

[Tanooki]

Fair enough, that makes sense. There are other problems with the 161 though (and it's smaller friends) such as the PCBs being made too thick so they eventually loosen up the cart pin slots on the board and that's over my head to pop off and fix. Then there are the other knowns such as broken games (2), various late betas (a few), a bunch of them with audio problems (quiet to deafening, drop outs, scratchy, etc.) It's all known. I've actually outside of Sengoku 3 on there and just a couple others own the ones I care about anyway so it's no real loss writing it off. I'd love Money Idol Exchanger but if I can get that Super Gameboy one for like $20 on ebay vs $300 for MVS I'd rather, not big on puzzles unless they're portable anyway. Might as well pass it on to someone who will enjoy it as it's mostly fighting games anyway on there.

 

That link in my signature, you can see I've rounded out to around 40 MVS carts which are a mix of most of the notable stuff not on the 161 and a good bit of the non-fighter goodies that are.

[Rick Dangerous]

What are people's thoughts on the Chinese NES multi carts (the 500 in 1, or 150 in 1 for example? Are those really going to fry an NES?

[+GoldenWheels]

What are people's thoughts on the Chinese NES multi carts (the 500 in 1, or 150 in 1 for example? Are those really going to fry an NES?

I've used my 150-in-1 for months now, but then again I'm not sure how long frying should take.

[Good_Times]

Are those really going to fry an NES?

 

I've enjoyed endless multicarts on various cart-based systems for 30+ years without experiencing anything even resembling a problem....in fact, one of my favorites, a Chinese jobber called 'JUMBO', never leaves one of my GBAs.

 

All consoles & handhelds remain firmly unfried.

[Good_Times]

but then again I'm not sure how long frying should take.

Well, it all depends, really. For potatoes and tubers, I like to give them a nice cold soak pre-fry. Now, for proteins such as chicken and fish, I like to first.....

[phoenixdownita]

Some measurement finally

https://db-electronics.ca/2017/07/13/ac-analysis-of-clamping-diode-effect-in-5v-to-3-3v-mismatch

 

Interesting to see how the issue is actually when reading from the internal RAM rather than the flash (as expected somewhat).

[Keatah]

From Good to Bad:

 

Vintage 5V console parts + 5V cartridge parts or 3.3V cartridge parts and level translators

Vintage 5V console parts + 3.3V / 5V tolerant cartridge parts

Vintage 5V console parts + 3.3V parts and pullup/pulldown resistors & diodes

Vintage 5V console parts + 3.3V parts

 

The first one being totally safe and in-spec. The last one being unacceptable and highly stressful to both itself and the console.

 

I wonder what other sorts of add-ons and mods and accessories should be put under the spotlight?

[phoenixdownita]

Original article has been updated with this:

 

EDIT 2:

After witnessing several complete misinterpretations of my article I decided there was 1 word in the article that needed to change:

• Avoid -> Use sparringly
  • This was my original intent, avoid as in “avoid getting drunk too often”.

Let’s be clear that this article is NOT fear mongering, nor should the article be twisted in that way. In the article’s introduction I clearly state that I am an Everdrive user myself. There is no hidden agenda, my only intent was to inform people of a design flaw. Also, the explosion picture above is meant to represent how you should dispose of your NES and Neogeo Multicarts (not Flashcarts), after all, these are the only which I recommend to not use and to “burn”.

TL;DR

Stop using your Aliexpress multicarts, keep using your Everdrives – but know the design flaw.

[Flojomojo]

I would think plugging your old consoles into relatively dirty house power would be a lot worse than any minor internal variation in voltage. If this were a major problem, wouldn't we have heard more about it? Not that the average person would be able to distinguish everdrive-related frying from component failure due to being thirty years old.

 

I don't own any everdrive stuff, nor am I an electrical engineer, but my ignorant wishful thinking says to keep calm and carry on.

[Tanooki]

So the guy back pedaled a bit on his alarmist style posting a little. That would have been better saying sparingly instead of eluding to will cause cancer and death.

 

But flojo is right, I would love someone to prove without any doubt a flash kit let alone some crappy chinese multi(single) game cart fried their hardware that happens to also be 25-35+ years old. Not very likely given none of it was ever designed to be the cockroach of electronics to ride out a nuclear blast.

[Osgeld]

yea AVOID with images of fireball's isnt alarmist in anyway

[Flojomojo]

"Use sparringly"

[Tempest]

So those 144 in 1 Neo Geo carts will fry your system?

[Tanooki]

His idea of use sparingly is kind of like those garbage ads for medicine on TV the last decade once the FDA loosened up and drug companies started killing a few people with side effects.

 

All kits and Chinese knockoffs now require disclaimer. Use of this product can cause mild cases of voltage, irregular behavior, apparent dimentia on your save games, and potentially death. Use sparingly and contact the company if any of these side effects occur. (As if you're dead you can call them to complain anyway.)

[Keatah]

Don't know for certain, the specs and design of each cart need to be evaluated to be certain. This means reading datasheets and comparing specifications. That engineering stuff.

 

I seem to recall someone having problems with a disk drive emulator that had 3.3V (5V tolerant) parts in it, no level translators. And it did something to the drive ports. On more than one motherboard. IIRC.

[Tanooki]

Like you said, no one at this rate really knows for certain without going at it as an engineer and looking at the actual boards and the spec sheet they're designed by. Looking from the outside in and poking at it can only go so far, even if it is quite a ways towards an answer. I wouldn't doubt some stuff perhaps that's more borderline along specs being more twitchy or failing, but keeping the scope narrow to video game consoles and kits/bootleg carts I've really never seen any proven cases stuff like that vaporized someones hardware.