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An Engineer's Guide to USB Typе-С (2024)

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Re: An Engineer's Guide to USB Typе-С (2024)

#41

Post by interloxia »

wredcoll wrote: post #38
mapt wrote: post #25

Earlier quoted context omitted.

My phone's USB-C port is worn out, and so now it's a brick if I don't have a wireless charging dock around. Is it physically impossible to get bandwidth and power out of something as durable as a Magsafe connector, even a larger-scale version?

How do you "wear out" a usbc port? Is this phone like 15 years old? My imagination is boggled.

My old Sony xz2c's USB C port wore out after about three years use. About the same length of time they bothered to update Android. :/

Re: An Engineer's Guide to USB Typе-С (2024)

#42

Post by mtabini »

elhart05 wrote: post #17

The EPR safety design is the part worth highlighting for anyone not deep in USB PD. The handshake is deliberately structured so a single message error can't accidentally push a port into a 100W plus contract, the sink has to actively drive entry into EPR mode and the source verifies cable capability before sourcing anything above 20V. That's a sensible failsafe given how much heat and current you're dealing with at 4…

Not only that, but EPR contracts must be actively maintained in order to remain in effect. The sink needs to send a ping to the source every ~500ms, or the source pops out of EPR mode and forces a renegotiation. This ensures that, if the sink crashes, the source doesn't keep pumping power into a device that can't take it anymore.

Re: An Engineer's Guide to USB Typе-С (2024)

#43

Post by mtabini »

Bit of self-promotion: I spent the last year or so designing an open-source USB-PD protocol analyzer[1], and the complexity of the protocol can be mind-boggling. Most of the time, the communication between source and sink is really straightforward, but it can get amazingly complicated when both devices are dual-role or come from the same vendor[2].

As messy as it is, however, it's also a very useful protocol that allows even small players to take advantage of the same economies of scale that large companies can take advantage of. Pity that the communication often requires dedicated chips, though thankfully those are relatively inexpensive. I was able to get an RP2350 (the same MCU that's in the Raspberry Pi Pico 2) to interface directly with USB-PD, but they could have made it easier and more accessible.

[1] https://github.com/T76-org/drpd or https://www.crowdsupply.com/t76-org/dr-pd [2] https://hackaday.io/page/399885-a-mac-and-an-ipad-walk-into-...

Re: An Engineer's Guide to USB Typе-С (2024)

#44

Post by ajsnigrutin »

leokennis wrote: post #29
kubb wrote: post #22

My new iPhone with USB C charging is such an improvement! Thank goodness for the European Union. If it weren't for them, we'd all be stuck with these flimsy Apple charging cables forever.

Even if Lightning was possibly a nicer or smaller connector; nothing beats a true industry standard. Makes the entire “what chargers and cables to bring to connect my stuff” question so much easier.

Sadly, that's far from truth...

"back in the day", you had an ericsson charger that fit in an ericsson phone and charget that ericsson phone well... and you had a nokia charger for you nokia that charged your nokia. They physically looked different, they wouldn't fit into any other device, and when you needed a charger, you'd take the one that fit the charging hole and it would charge.

Now, you have a bunch of usb C bricks, some just 5V usb, some USB PD, some QC(2, 3).... then you have a bunch of usb C cables, some with ID chips, some without, some able to carry 15 watts, some 100 watts, and then you have devices, some that can do QC, some that can do smart PD, some with just some resistors, some without even those.

Everything fits in every hole, every charger can take any cable and any device can take the other end of the cable.... but will this particular combo charge your laptop? The cable fits.. will it charge? What about those cheap earbuds that just want 5 volts? The USB-A to usb-C cable that came with them works, but the USB-C to USB-C that you bought after, doesn't. How about that smart LiPo charger, it's USB-C, but it needs at least 9 volts to charge, and not every power brick gives out that voltage. What about charging speed? Will it do fast charge? Your laptop charging light is on, but the battery percentage is going down... why? What about a powerbank, does it charge your laptop? How does it know who does the charging, and who is getting charged?

I mean sure, if you know your standards, you'll know what devices need PD and which ones use QC, you'll read the specs on the power bricks, you know how many watts your laptop needs, how to switch the current directions, which devices can't do proper handshakes, and need usbA->C cables, etc, and you'll get yourself a baggie of a few power bricks and cables for different stuff, but i had to label the cables for my mom, because while everything physically fits, many combinations won't actually charge your device. 10 years ago, this wasn't a problem, since her laptop charger didn't fit her wireless earphones, now it fits and it doesn't charge them.

Re: An Engineer's Guide to USB Typе-С (2024)

#45

Post by Kirby64 »

hutattedonmyarm wrote: post #40
gwbas1c wrote: post #30

Earlier quoted context omitted.

> the lightning connector itself is better than the usb-c connect in my opinion. I get that having the pins on the male* plug is a theoretical advantage in durability but that has not been my experience with usb-c connector durability on either end. I always end up picking a lot of dust out of my usb-c ports on my phones; or otherwise the port wears out and disconnects before charging completes. (Right after my wife…

> I always end up picking a lot of dust out of my usb-c ports on my phones Lightning has the same issue sadly

The advantage of Lightning here is there is a totally open port, so picking lint out of the port is substantially easier. With Type C you have to work around the 'tab' and it requires much much smaller tools.

Re: An Engineer's Guide to USB Typе-С (2024)

#46

Post by rconti »

kubb wrote: post #22

My new iPhone with USB C charging is such an improvement! Thank goodness for the European Union. If it weren't for them, we'd all be stuck with these flimsy Apple charging cables forever.

honestly, the lightning CONNECTOR was far better, but man, I really appreciate the standardization. We have one device on the house left using lightning (my wife's iPhone 13 mini) and .. well, I just wish they'd release a new mini, that's all.

Re: An Engineer's Guide to USB Typе-С (2024)

#47

Post by ocimbote »

ajsnigrutin wrote: post #44
leokennis wrote: post #29

Earlier quoted context omitted.

Even if Lightning was possibly a nicer or smaller connector; nothing beats a true industry standard. Makes the entire “what chargers and cables to bring to connect my stuff” question so much easier.

Sadly, that's far from truth... "back in the day", you had an ericsson charger that fit in an ericsson phone and charget that ericsson phone well... and you had a nokia charger for you nokia that charged your nokia. They physically looked different, they wouldn't fit into any other device, and when you needed a charger, you'd take the one that fit the charging hole and it would charge. Now, you have a bunch of usb C…

You may be right, and I've had to live some of that myself with docking stations, thunderbolt, and such.

But those moments are the exceptions. In my everyday life, when I need to charge _anything_, except maybe for the laptop itself, I just look for a charger with USB-C and it works. It maybe faster or slower depending on everything you just wrote, but it works.

On a side-note, when I take the charger of my laptop, it can charge absolutely everything.

So yes, that's a true and honest improvement.

Re: An Engineer's Guide to USB Typе-С (2024)

#48

Post by tonymet »

kubb wrote: post #22

My new iPhone with USB C charging is such an improvement! Thank goodness for the European Union. If it weren't for them, we'd all be stuck with these flimsy Apple charging cables forever.

Give it time. I have 10+ year lightning connnectors working great. usb c isn’t quite as sturdy

Re: An Engineer's Guide to USB Typе-С (2024)

#49

Post by [deleted] »

ajsnigrutin wrote: post #44
leokennis wrote: post #29

Earlier quoted context omitted.

Even if Lightning was possibly a nicer or smaller connector; nothing beats a true industry standard. Makes the entire “what chargers and cables to bring to connect my stuff” question so much easier.

Sadly, that's far from truth... "back in the day", you had an ericsson charger that fit in an ericsson phone and charget that ericsson phone well... and you had a nokia charger for you nokia that charged your nokia. They physically looked different, they wouldn't fit into any other device, and when you needed a charger, you'd take the one that fit the charging hole and it would charge. Now, you have a bunch of usb C…

[deleted]

Re: An Engineer's Guide to USB Typе-С (2024)

#50

Post by tonymet »

A helpful guide, but usb c usability from a consumer standpoint is atrocious. From the specs it runs so many modes, PD (at various power levels), classic 5v , alternative modes. Sadly, there’s no way of knowing which mode a device or cable is supporting.

They could have done a better job color coding the connectors like resistors, so you could know the protocols supported by the cables and devices.

I have to label my own cables according to data support, PD, max power, etc. And many of my “usb c” devices only work with usb-A to usb-C cables.

The connector design targeted the industry and not consumers. Hopefully they will improve that.

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