USB-C Host Port Schematic Suggestion

[sakibnaz]

Hello there. I made a custom PCB with USB-C Host Port and an RK3128 ARM SoM running Linux.

I am facing a problem in my Board with USB-C Host.

- When I attach a regular PenDrive (with a Type-C to USB-A Female adapter cable) everything works. I can see that PenDive is detected by Linux.

- But when I attached a Samsung T7 SSD with a Type-C to Type-C cable then it did not detect .I tried different cables but no luck.

Below is some portion of my schematic block.

Any suggestions?

Regards.

 

[FvM]

Missing connection of CC pins.

 

[sakibnaz]

Missing connection of CC pins.

Thanks or reply FvM. But as per my understanding, its USB 2.0 Host Port. There are no SuperSpeed SSRX/SSTX lines for Orientation Detection. Hence I did not add any CC lines.

Please clarify if I am wrong.

 

[BradtheRad]

This may or may not be the root of your problem but recently I saw a Youtube video revealing seldom understood but big differences in USB-C cables, namely the type costing $10 and the other type ('Apple') for $130.

Both types were X-rayed. The cheap cable can do cell-phone charging and not much else.

Conversely X-rays of the expensive cable revealed it contains computerized circuity that made it capable of a much wider range of tasks, including rapid data transfer.

 

[sakibnaz]

This may or may not be the root of your problem but recently I saw a Youtube video revealing seldom understood but big differences in USB-C cables, namely the type costing $10 and the other type ('Apple') for $130.

Both types were X-rayed. The cheap cable can do cell-phone charging and not much else.

Conversely X-rays of the expensive cable revealed it contains computerized circuity that made it capable of a much wider range of tasks, including rapid data transfer.

Yes that can be a cause. So for USB 2.0 based Type-C HOST connector don't need CC pins ... it can be float like my design ... Am I correct?

 

[BradtheRad]

You've reached a level where one little change might make the project work. I have no more information than my reply above. If you can find a way to obtain verbose reporting from your devices then that should help you to diagnose.

The usual advice is 'Leave no input floating. Connect every input to a supply rail even if through a medium-ohm resistance.'

It looks as though manufacturers are trying all different tactics to satisfy demands for speed in our computerized devices. Just the introduction of USB seemed to be an enormous breakthrough years ago. Now they're revising it, upgrading it, combining protocols with ThunderBolt while trying to comply with all other protocols. Consumers can barely keep up with marketing tactics.

 

[FvM]

Why not refer to USB standard? It clarifies that CC has to be connected in the USB 2.0 host and cable. Only an USB 2.0 C to A or B legacy cable doesn't use it.
CC is required for host/device role determination. An USB-C device uses it during connection initialization.

--- Updated Apr 15, 2024 ---

Adding Rp according to available power should work.