Originally posted by: Kosmic StarDust
Originally posted by: Great Hierophant
I would strongly urge everyone never to use these cartridges or anything like them (which appear to include the FF7 Repros and those 8-bit Music Famicom carts) on official/real hardware. They are dangerous to vintage hardware, as described in better detail here :
https://db-electronics.ca/2017/07/05/the-dangers-of-3-3v-fla...
Leave them to the clones, which they appear to be designed for anyway.
I'm going to rebutt this article for a moment. I first read this the other day but I think the risk to hardware is grossly exaggerated. If anything this article is perpetuating fear mongering against unlicensed devices, whether the source is Far East bootlegs or botique flash carts...
I can and do run clones and everdrives in my hardware, as you well know from my Music Machine dumps. These flash chips are not shorting the CMOS logic to ground; in fact there's barely more than 1V of droop on the output if that, and I'm skeptical they are really pulling anywhere near 12mA per output. Yes, the voltage output will droop a bit, but it's no worse than original cart hardware that exibits "bus conflicts" or other issues. During a "bus conflict" event, the on cart logic circuit attempts to write a different value to a register compared to the CPU. Bus conflicts can and do occur on bidirectional busses, and typically with CMOS the grounded output wins over the high logic output. Since the high outputs are weaker than low output, and it is the high output being pulled low, if CMOS or TTL logic chips (yes they are different families with different characteristics but I'm not going down that rabbit hole) are designed robustly enough so that during a bus contention event, they fight each other, pulling high outputs low enough to register a low signal on another input (LOW logic <= 0.8v according to specs), without damage to either logic chip, then I don't see how a 5V CMOS chip, which does not see damage when a high logic output is pulled down to below 0.8V during a common bus conflict event, is going to see any damage at all when a high logic is pulled down to 3.9V. The maximum current ratings is the maximum current the chip is capable to supply while maintaining a proper logic level within specs. Exceeding this threshold the chip won't burn up, but the signal level will experience brownout. These electronics are built by design to have relatively high output impedance characteristics dealing with signal logic, such that overloading the output will never cause enough internal heating to burn anything up. The chip may run say five degrees warmer above ambient temperature, but certainly it won't get scalding hot, and certainly not generate enough heat to achieve a thermal runaway scenario or reach breakdown temps at the silicon junction.
Room temp 25C. Body temp 37C. Water boils at 100C. Solder melts around 200C. MOSFETs break down above 300C.
There are exactly two ways to destroy MOSFET transistor junctions, one is to exceed the breakdown voltage, ie through an ESD event, which occur well above the nominal 5V or 3.3V operation. The other failure method is extreme heat. Enough to cause the junction to literally break down and release it's magic smoke. Sure, operating logic at well above rated voltage will cause thermal issues. Twice the voltage is equivalent to twice the current and four times the heat dissipation in a purely resistive load, but it is worse with semiconductors. Silicon diodes have a nominal voltage drop of .6-.8V, and any series of logic will have series voltage drops in addition to some resistance threshold. Generally the junctions also pass more current when changing state than when steady. So small increases in voltage will consume more current and power than small increases to a purely resistive load. But the 5V logic isn't being operated over 5V, it's just sinking excess current into the 3.3V device. And look at how insanely huge those DIP 5V chips are compared to the 3.3V SMT parts. That cockroach sized CPU or PPU or whatever vintage 5V processor could dissipate an order of magnitude more heat before it burns up than that tiny housefly sized logic chip on your unauthorized device. I would be far more concerned with the safety of your unauthorized device running at 3.3V and interfacing with a higher voltage logic bus than I ever would be with your console's 30-year-old 5V hardware.
End Rant.
Also dayum. Oh, snap! The only burning you'll see is from that rebuttal. lol