This is a feature of newer usb-c pd chipsets.
See, e.g., https://www.ti.com/product/TPS25751 in the features section.
Apple has historically used TI chipsets for their USB power controllers. The feature likely comes from this.
See, e.g., https://www.ti.com/product/TPS25751 in the features section.
Apple has historically used TI chipsets for their USB power controllers. The feature likely comes from this.
"The TPS25751 supports liquid detection by measuring the voltage level across the SBU pins of the Type-C connector. When a short occurs across the SBU pins to another Type-C pin(s), the TPS25751 takes action to protect the the Type-C port by disabling the power paths and notifies the embedded controller when applicable. Once liquid has been detected, the TPS25751 continuously monitors the SBU voltage. During the SBU voltage monitoring, if the liquid/short is no longer present the TPS25751 takes action to return to normal operation."
In other words, it's not actually detecting "liquids" but more of any conductive short. Non-conductive liquids, like oils and many other petroleum products, won't be detected.
Mostly yes, except for things like concentrated sulfuric acid which is highly corrosive but a bad conductor.
(And I'd probably watch it).
OTOH, I haven't seen any USB certifications on Apple USB cables or devices, so most likely Apple doesn't care.
This actually replaced the analog audio mode (good riddance- whoever thought adding analog audio into a port that also does digital audio was a good idea?)
Basically, it's only supposed to be used for USB-C-to-3.5mm adapters, and it was only implemented by some smartphones. It's not a reliable way to get audio out of a USB-C port, and because it's using the internal DAC the audio quality isn't going to be good anyways.
The proper solution is to use a USB DAC. This provides the same user experience but it actually works with all USB-C devices. Considering the official Apple USB DAC is available for $9, the Audio Alt Mode really doesn't have a reason to exist.
Unless I'm misunderstanding the mode, there could be uses to get audio out of a USB port that don't involve phones...
The ability to make this tradeoff should be up to the user.
The USB connector is detecting a short circuit--a direct connection between the two pins--and cutting power while the condition is present. If you wanted to put this in terms of household electrical, this would be closest to a self-resetting breaker. (And actually, most devices you have already _have_ this. There's usually a self-resetting fuse/PTC thermistor protecting your USB ports from over-current conditions. The only novel thing here seems to be that it's done in software.)
A GFCI, meanwhile, works by detecting in imbalance between the hot and neutral lines. The amount of current flowing through one should match the amount flowing through the other. If power is being drawn through the hot pin but not returning through the neutral, it has to be going _somewhere_ and it's not where we intended it to go. It cuts the power off rather than let it continue to flow out and find a path to ground through your kitchen sink/etc.
Even more nitpicky: it’s not a GFCI because GFCI does not detect current leakage between pins that shouldn’t carry current. It measures current imbalance between pins that should be carrying current.
The distinction is that a real GFCI (which this USB port is not) does not care whether the imbalance is returning through a third conductor on the power cord or some other path.
If this were a real GFCI, it would be able to detect when current flows out through the case, to your hand, though your body and then back though the puddle of watch you’re standing in.
That’s not what this is doing. It is measuring unexpected current between the pins within the port for the purpose of avoiding galvanic corrosion (the hint is in the daemon name reported by macrumors).
Smells of bad engineering - do they also have a batteryislowd? or a someonepressedtheMkeyonthekeyboardd?
> someonepressedtheMkeyonthekeyboardd
"Pages would like to access the 'M' key"
"Open System Preferences" "Deny"
It prevents the device from applying/draining power from any pin in such a state, mainly to reduce corrosion of the contacts and increase longevity.
(Without such a mechanism, an IPxx device may be unable to charge within a few weeks as the contacts of the connector can deteriorate quite fast)
As to why Apple ported the daemon from iOS to macOS....well, for sure a good indicator to reduce warranty repair-costs...
Less frequent of an issue for laptops I would hope :D