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Comment by ssl-3

6 hours ago

Oh, it's fine.

The lack of clarity is in keeping with the USB C connector itself, which may supply or accept power at various rates or not at all, may be fast or slow, may provide or accept video or not, and may even provide an interpretation of PCI Express but probably doesn't.

It probably looks the same no matter what, and the cable selected to use probably also won't be very forthcoming with its capabilities either.

(Be sure to drink your Ovaltine.)

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ssl-3

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wongarsu  3 hours ago

The USB A connector stayed the same between USB 1, 2 and 3. Yet most manufacturers voluntary distinguished them by giving USB 1 and 1.1 a white insert in plug and port, USB 2 a black insert and USB 3 a blue one

This was neither standarized nor enforced, yet it worked remarkably well in the real world

Then we decided to just have no markings at all on USB C cables. On the ports at least we occasionally get little thunderbolt or power symbols

  • mbreese  2 hours ago

    The exterior of the USB A connector stayed the same. The number of pins increased when we went from USB 2 to 3. So, even in this case, it’s slightly more complicated. The colors helped because the capabilities were very different between the ports. But when the USB IF increased the number of options (and reduced the size of the connector), different colors became impossible to do.

    The problem is that there are too many uses for one connector. But this is wha we wanted - a reduced number of standardized connector/power options.

tomchuk  2 hours ago

… and a M1 MacBook will source 5V/3A all day long to a non-PD negotiated sink. Somewhere between the M1 and M3 Apple decided to buy into USB-IF compliance and limit to 500mA.

Has lead to some very embarrassing “works on my computer” situations on prototype boards shared with my EE colleagues (I’m a software guy who dabbles in hardware when I need to)

  • eigen  1 hour ago

    I think the Rd pulldown options are for 0.9/1.5/3A without PD negotiation.

reaperducer  2 hours ago

The lack of clarity is in keeping with the USB C connector itself, which may supply or accept power at various rates or not at all, may be fast or slow, may provide or accept video or not, and may even provide an interpretation of PCI Express but probably doesn't.

It gets even worse.

I now have two cheap Chinese gadgets (a checki printer and a tire inflater) that have USB-C ports for charging, but will only charge with the wire that came with the gadget. The other end of which is an old-style USB plug.

It seems that USB-C sockets are cheap enough parts to use them for everything, even if the manufacturer isn't going to put any actual USB circuitry behind them.

Edit: Three. I forgot about my wife's illuminated makeup mirror.

  • the__alchemist  43 minutes ago

    Note: If it just needs 5V power (Like many microcontroller-focused devices), USB C is convenient, because chargers and cables are ubiquitous. And they all (WIth exceptions like the one you mentioned) support 5V DC power.

    Bonus: YOu can enable USB 2.0 data transfer as well for firmware updates, computer interfaces etc.

    So: Cheap/ubiquitous part, everyone has cables + AC adapters to their local plug: I think it's a great default power connector.

  • ziml77  1 hour ago

    Ah that's a fun misuse of USB ports. The companies will often even dodge issues with the USB-IF by labeling the ports as Type C and letting the customer's mind fill in the word USB.

    I wish these devices would just use barrel jacks, labeled with the voltage and polarity. But these manufacturers know that the USB-C port weighs into buying decisions (and they know that most people have zero clue about the difference between a physical port and the electrical/protocol specs).

    • SoftTalker  1 hour ago

      I hate barrel jacks, it seems that every single time I encounter one it's different from any adaptor I have. Size, voltage, and polarity can all differ. People got sick of having 10 differnet power adatpters to charge stuff. Hence the demand for "single connector" which seems to have converged on the USB-C form factor.

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