Re: Multiple USB 1.1 devices in USB 2 Hub speed ?

On Wed, 16 Jul 2008 16:55:14 -0700 (PDT), Adrian
<adrianbica@xxxxxxxxx> wrote:

On Jul 16, 5:41 pm, Anton Erasmus <nob...@xxxxxxxxxxxxxxxx> wrote:
Thanks, this what I needed to know. So if I need to combine 6 full
speed devices into one High speed channel, I would need something with
6 1.1 host ports and one 2.0 device port.

Basically, yes, but you need 2 host controllers to take care of those
this devices, one would not be enough, because of the high bandwidth
( 6 x 3Mbps). This should be two independent controllers, not a
controller with 2 ports, those just have an internal (root) hub. And
be sure the 2.0 device controller is a real 2.0, many controllers
pretend they are 2.0 but limited to full speed.

available that does this kind of thing? I have six USB 1.1 devices
(FTDI chips in FIFO mode) each needing to send data at 3 Mbps to
a host PC. The PC has 6 USB ports, but I need to take these through a
sealed bulkhead, and the connectors I can get is to big to fit 6 of
them. So I either need to get smaller IP-67 sealed USB connectors, or
a way to combine the data into a single channel. I might be able to
fit 2 USB connectors in which case the Full Speed limit per channel
should be OK.


The PC also should have more than one internal USB host controllers,
if it is just a hub, it won't do the job.

Thanks, I did not think of this. Is an internal USB hub the norm for
PCs, or is it normally more than one host controller ?

Regards
Anton Erasmus
.