41–50 of 146 posts
USB-C seems like a really bad standard if the cable can destroy expensive electronics. EDIT: Even if the cable is wired and built correctly (which is apparently difficult for manufacturers to get right), cables fray and tear all the time. I foresee a lot of dead electronics upcoming.
Killed a laptop when plugging in my phone (with the old 30 pin connector). Turns out a bit of foil from a wrapper had become stuck in the slot on the phone. Since this was in the bad old day the laptop was fixable for under $200 so it wasn't too bad. Still, makes sense to keep an eye on what you plug into your computer.
I would love to know where or how I could repair it for and how much.
TL;DR; USB-C cable had GND tied to Vbus and Vbus tied to GND (opposite as it should be) Honestly, I'm surprised that this isn't something that thelaptop and other such USB adapters aren't equipped to deal with. This is only slightly worse in my book than a USB adapter being fried from shorting the Vbus and GND pins together
Why would you design in reverse polarity protection? It adds cost, and the mechanical connector already makes it impossible for VDD to short to GND in USB type C because of its rotational symmetry.
TL;DR; USB-C cable had GND tied to Vbus and Vbus tied to GND (opposite as it should be) Honestly, I'm surprised that this isn't something that thelaptop and other such USB adapters aren't equipped to deal with. This is only slightly worse in my book than a USB adapter being fried from shorting the Vbus and GND pins together
The protection against reversed voltages like that would be a crowbar diode between Vbus and GND, to convert the negative voltage into a short circuit. But even if it had that reverse protection, if the current was high enough (since the negative voltage was from a charger, it's not unlikely) the diode could burn open, and then you have negative voltages again. And I don't know how common these crowbar diodes are; they probably are rare, since the USB connector is keyed so it can't be plugged "backwards" (the type C connector is mirrored instead, either orientation connects the pins the right way).
Earlier quoted context omitted.
unless the connector were cut, or some other catastrophic failure. I tend to think ruining a devices USB controller should be near impossible short of something like the USB killer ( http://arstechnica.com/security/2015/10/usb-killer-flash-dri... )
I was playing with a FTDI (a clone :D) and an Arduino and accidentally mixed up VCC and GND from an external power source. I only realised because Minicom was failing to connect to the device. Then I realised what I had done, I tried removing it from the USB port and putting it back in, but it wouldn't work. I then tried a mouse too, but that wasn't working either. Thinking I'd killed a USB port on my Mac (well there…
HN has previously had a story on the author, a Google engineer who tests USB-C cables on Amazon to make sure they're spec-compliant. He does some amazing work: https://news.ycombinator.com/item?id=10508494 I don't have any devices right now that use USB-C, but whenever I see a deal pop up for one, I usually check the Amazon listing to see if this guy has reviewed/certified the cable yet. I recommend others do the sam…
Frankly the C plug spec seems overly convoluted. Each cable needs one of 3 resistors depending on them being a A/B-to-C cable, 1.5A C-to-C cable, or 3A C-to-C cable. Note that the A-to-C cable may well be able to carry 3A, but it shall never use the 3A C-to-C resistor (what many of the cables he find as faulty does). Note that all this resistor shenanigans are all independent of the Battery charging spec that has bee…
No, for C-to-C connections, the resistance is provided by the host ("downstream-facing") port, not the cable. The resistor in an A-to-C cable is basically emulating the signal that would otherwise be provided by the host.
There's no such thing as a "1.5A C-to-C cable"; all type-C cables are required to deliver at least 5A. The limiting factor is the host, not the cable, which means the cable must not incorrectly advertise capabilities that the host doesn't support.
> Never mind that a C port has so many extra pins compared to a A or B port, that one would think that id-ing a A-to-C cable would have been as simple as looking for life on any of those extra pins.
That's exactly what the new CC pin is used for. Right now the spec says "legacy cables should connect CC via a 56kΩ resistor", but it wouldn't matter if instead the requirement had been "legacy cables should leave CC disconnected"; the issue is that cable manufacturers are ignoring the spec.
Earlier quoted context omitted.
Yes, and that's why the USB spec puts the burden of protecting against electrical shorts on the controller. The device side shouldn't have to worry about trying to shunt 100 Watts of power somewhere. I mean this kind of protection is way beyond typical ESD protection due to the power involved. It would add a lot of cost to do this, maybe even a dollar or two in raw material.
If you stop the current from flowing, you don't have to shunt any power anywhere. You'd have to open the circuit in the face of 5V of potential hooked up backwards, not really a tall order.
Earlier quoted context omitted.
unless the connector were cut, or some other catastrophic failure. I tend to think ruining a devices USB controller should be near impossible short of something like the USB killer ( http://arstechnica.com/security/2015/10/usb-killer-flash-dri... )
I was playing with a FTDI (a clone :D) and an Arduino and accidentally mixed up VCC and GND from an external power source. I only realised because Minicom was failing to connect to the device. Then I realised what I had done, I tried removing it from the USB port and putting it back in, but it wouldn't work. I then tried a mouse too, but that wasn't working either. Thinking I'd killed a USB port on my Mac (well there…
I know because I've triggered it doing something with an arduino.
Earlier quoted context omitted.
Yeah, that's what the amazon review details. The ground is miswired.
The question isn't what was wrong with the cable, but whether it was just this one specific cable, or whether it's all of the cables in from this production run.
HN has previously had a story on the author, a Google engineer who tests USB-C cables on Amazon to make sure they're spec-compliant. He does some amazing work: https://news.ycombinator.com/item?id=10508494 I don't have any devices right now that use USB-C, but whenever I see a deal pop up for one, I usually check the Amazon listing to see if this guy has reviewed/certified the cable yet. I recommend others do the sam…
Frankly the C plug spec seems overly convoluted. Each cable needs one of 3 resistors depending on them being a A/B-to-C cable, 1.5A C-to-C cable, or 3A C-to-C cable. Note that the A-to-C cable may well be able to carry 3A, but it shall never use the 3A C-to-C resistor (what many of the cables he find as faulty does). Note that all this resistor shenanigans are all independent of the Battery charging spec that has bee…
It's just as complicated as it needs to be. And for godssakes, the pin-out diagram isn't that complicated; it only has 24 pins! There's no excuse for flipping two of them. 24 pins is not beyond the pale of what we would reasonably expect manufacturers to be able to wrap their heads around.
http://bi9he1w7hz8qbnm2zl0hd171.wpengine.netdna-cdn.com/wp-c...
