12 of 14 people found the following review helpful
Using with a Raspberry Pi,
Verified Purchase(What is this?)
This review is from: Transcend HUB3 4-port USB Hub - USB3.0 - with power supply (Personal Computers)
The Raspberry Pi requires a maximum of around 750 mA to be supplied via a micro USB port. (There is a 'polyfuse' of 750 mA).
The Raspberry Pi also has USB2 port for data communications.
The power that can be supplied by the Raspberry via its USB2 ports is limited. Insufficient to power USB drives and, probably, WiFi adapters. Hence the need for a powered USB hub.
I had planned to supply power via the TS-HUB3K "dedicated fast charging port" and use the other 3 ports for communications.
This will not work and Transcend have offered no solution.
The problem is that the Raspberry Pi boots when power is supplied, however shortly later the Raspberry activates it's USB2 ports and thus the hub's 'upstream' port. The hub reacts by momentarily interrupting the power supply. This causes the Raspberry Pi to reboot and the sequence loops. The power supply LED on the Raspberry flashes (about once a second).
However, there is a way around this problem. But this means that power cannot be supplied via the 'dedicated fast charging port'.
The solution is to power the Raspberry via one of the other hub's ports - NOT the 'dedicated fast charging port'
The USB3 standard says that a USB3 port can supply up to 900 mA (USB2 is 500 mA). If (this has not be confirmed) the Transcend port does this then this should be sufficient to supply the 750 mA needed. It might be the hub sees an 'upstream' port of USB2 not 3 and therefore limits to 500 ma.
In practice I have successfully run a Raspberry in this way with an external USB disk and WiFi adapter.
Also to get more power from the 'dedicated fast charging port' requires special drivers that are only available on Windows or OS/x
i.e. not the the Raspberry Pi Atom.
Finally it may need care on what devices are supported via the 'dedicated fast charging port' - they would need to tolerate a power interruption early in the boot process. WiFi OK?, hard disk used soon after boot?
In summary, I would say that I am happy with the port for use with a Raspberry Pi but that there are some limitations that had to be investigated at some considerable investment in time.
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Initial post: 14 Apr 2014, 13:00:42 BST
Thanks for this info. I'm using one of these hubs on my PC and planning to buy a second one as an expansion hub for the Pi, (it seems pointless to buy a USB2 hub these days) so I much appreciate your time and trouble to 'publish' this info.
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