An Engineer's Guide to USB Typе-С (2024)
189 points
6 days ago
| 7 comments
| ti.com
| HN
kubb
29 minutes ago
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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.

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rjh29
2 hours ago
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Pretty good summary. It can be confusing since type C is "just a connector" but it's pretty heavily coupled with the protocol now.
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imtringued
2 hours ago
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Guides like this explain why there are so many broken USB-C devices. The guide mentions that you do not need a PD chip for 5Vs, but then tells you that USB C is a cold connector meaning 0V is on VBUS when nothing is connected and jumps straight into the complexities of the PD protocol running over the CC pins instead of explaining how to get the 5V without the PD chip first.

Then in the section where it tells you how to do that, it fails to properly explain how to connect a load switch (10 cent component at 100 units) to get around the 10uF limit. The vast majority of applications will require less than 15 W and a good chunk of them can't get away with 10uF between VBUS and GND so a schematic how to do it in the lowest cost way would have helped here.

Edit: After reading until the very end I got the impression that this is just an ad for Texas Instruments PD controllers.

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crote
1 hour ago
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Basic 5V devices just need a 5.1k resistor on each CC pin to GND. It is pretty obvious when reading the actual USB-C Connector Specification.
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dvh
1 hour ago
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Now I want to know, how to add larger than 10uF cap?
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wolfi1
4 hours ago
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there is a timestamp as parameter, I don't know, what it is good for, but the link works without it as well
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account42
4 hours ago
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Might be for cache busting.
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wolfi1
3 hours ago
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could be, but for pdf documents I would assume that they are not changing this much
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crote
1 hour ago
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TI usually links to chip datasheets, which do tend to change from time to time. Having both a reference to a specific revision and a trivial link to the latest revision is quite handy in practice.
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Lex-2008
2 hours ago
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timestamp corresponds to Oct 08 2025, so probably the last time the file was modified
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delis-thumbs-7e
4 hours ago
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Nice one. I need to read this later.
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qwertox
7 hours ago
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Good find!
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faangguyindia
3 hours ago
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I use an Apple Silicon Mac and often use programmable keyboards like the Royal Kludge RK61 via USB C. when I press keys such as A, S, D, F, W, or nearby keys in quick succession, the keyboard stops responding completely until I unplug and reconnect it. I've even replaced the USB C cable with a new store bought cable, but the issue still persists.
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DaSHacka
2 hours ago
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Check if your keyboard has a way to enable n-key rollover (NKRO)

https://en.wikipedia.org/wiki/Key_rollover

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faangguyindia
1 hour ago
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You are genius! thanks this completely solved my issue, for those curious https://postimg.cc/75hV9tCK

I use usevia, all i had to do was find a keyboard definition file for my keyboard which claude found in 2 minutes!

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rjh29
2 hours ago
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Usb isn't the issue, you bought an extremely budget mechanical keyboard.
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thenthenthen
2 hours ago
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Also avoid Epomaker, had the same issues, but needed a full reflash (every other day), losing all my layers etc. (The import function was broken lol)
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faangguyindia
1 hour ago
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turns out it was just me not knowing my keyboard has full qmk support and can be configured via usevia, what N-key rollover (NKRO) is.

my keyboard is actually r65 by royal kludge i got that wrong!

I was gifted this keyboard and i just love its feel.

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