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bigmik

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Joined: 20/06/2011
Location: Australia
Posts: 2914

Posted: 03:06am 30 Jun 2023

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Hi All,

I recently bought several (all different types) of USB3 A-C cables to power my bench mounted USB3 4 port Hub, The image below looks identical to the one in question.

This is fed from the PC's USB3 port via a USB3 A-A cable from the underneath (The white cable) This cable is supplied with the unit and is a USB3 A-A type, it works fine but is a bit short on length.

In my wisdom, I chose to buy USB3 A-C cables as my PC has a couple of USB-C sockets handy.

To my surprise every one of these new cables did not power the HUB.

I did suspect that these were all POWER cables and not meant for data but I tested them with an external HDD that has USB-C and they are all fine.

So my question is:

Why will power go FROM USB3-A TO USB3-C perfectly but not the other way?

I am sure there is something I am missing but a search on Dr Google didn't prove fruitful.

Regards,

Mick

Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<<

phil99

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Joined: 11/02/2018
Location: Australia
Posts: 2137

Posted: 03:53am 30 Jun 2023

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Something worth a try, not all USB-C plugs are wired the same on both sides so try turning the plug over and see what happens.

Mixtel90

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Joined: 05/10/2019
Location: United Kingdom
Posts: 6798

Posted: 06:37am 30 Jun 2023

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A USB-C socket won't necessarily deliver power even though the VBUS pins are connected, it may only accept it. It's a very clever system. :) It depends on data on the CC1 and CC2 pins to configure how it's going to work.

You need termination resistors on CC1 and CC2 to tell the power source to provide 5V to the USB-A connector and these are missing. A 5K1 pull-down resistor on one of the CC pins tells the host which way up the plug is. The value of it also tells the host which current level is required. Unfortunately CC1 and CC2 aren't run through to the USB-C connector.

You can get USB-C plug to USB-A female adapters and leads specifically for this job.
Edited 2023-06-30 16:38 by Mixtel90

Mick

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Preliminary MMBasic docs & my PCB designs

bigmik

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Joined: 20/06/2011
Location: Australia
Posts: 2914

Posted: 06:59am 30 Jun 2023

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Hi All,

@Phil,
Sorry Cant do that, its a Type A at the HUB and type C at the other end of the cable, I was hoping to plug that into my PC's Type C port

@Mick
That makes sense, I think that may be the reason, If so I cant see a neat way around it.
I don't want to modify my PC port and CC1 and CC2 will presumably not be connected in the socket end of the cable and I don't feel like cutting away the neat moulding of the cable.

I could make a breakout board using a male and female type C. I will see what I have lying around here, or I may order a couple of connectors.

Or better still may order a longer USB3 A-A cable.

Thank you for your replies.

Regards,

Mick

Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<<

phil99

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Joined: 11/02/2018
Location: Australia
Posts: 2137

Posted: 08:14am 30 Jun 2023

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Quote Sorry Cant do that, its a Type A at the HUB and type C at the other end of the cable

I should have been clearer. It is the USB-C plug that you turn over, not an end to end swap. The USB-C plug has two sets of contacts so you don't need to know which way is up but on some cables they don't wire all of the second set. That doesn't matter if the socket has both sets fully wired, but not all do.

bigmik

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Joined: 20/06/2011
Location: Australia
Posts: 2914

Posted: 08:29am 30 Jun 2023

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Hi Phil, All,

Except the hub only has a type A input, I will look at doing a breadboard adapter for the learning experience as I find it interesting.

However I have bought a proper 1.5m A-A usb3 cable as the original is only 1m and fits, just, I can bump the cable as it’s a bit on the tight side, the extra 0.5m will give me a bit more ‘wriggle room’.

The A-C cables will find a good home as I see TYPE-C the future of usb.

Regards,

Mick

Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<<

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