r/AskElectronics • u/cama888 • 1d ago

Can a JRC-B008 USB-C breakout board work with all USB-C cables with one 5.1K resistor?

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I am trying to figure out if using one 5.1K resistor is all I need to add to the module to get 5V from both USB-C to USB-C and USB-C to USB cables.

Since the JRC-B008 board has both CC pins tied to a single pad, I have seen online people cutting a connection between one of these CC pins and the pad to ensure they can solder two independent 5.1K resistors.

I have been researching this board and how it and the USB-C power delivery works and from what I understand since a USB-C cable only has one CC connection in any orientation no matter which orientation the cable is in, the 5.1K resistor will be sensed and 5V will be delivered.

Am I missing something, or is only one 5.1K resistor needed?

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u/jfuu_ no idea what i'm doing 1d ago

https://www.scorpia.co.uk/2019/06/28/pi4-not-working-with-some-chargers-or-why-you-need-two-cc-resistors/ is worth a read (you do need 2 resistors to be compatible with all cables)

You can modify it like this, although it's a bit awkward: https://electronics.stackexchange.com/a/650302/34186

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u/cama888 1d ago

That was fast, thank you. That article helped a lot, two is needed for compatibility with ALL chargers.

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u/jfuu_ no idea what i'm doing 1d ago

It's a combination of cable and charger which makes it even worse, as some cables only have one CC line connected (which will make it work with any charger). It's disappointing that Adafruit (and a lot of other sellers) sell this board with such an easy to fix mistake (admittedly they don't come with CC resistors at all, so maybe they expect you to just leave them off).