Question on USB2

Thread view:

Enable EMail Alerts

Start New Thread

Thread rating:

gecko - 26 Jul 2008 00:35 GMT

Prev posted in wrong group mouse slipped sorry

I have read that the word 'enhanced' in Device Manager indicates my
machine has USB2. Now then - I have eight USB ports. Are they all
USB2? Is there some utility that will tell me which if not all are
actually running at USB2 speed? I fear that some may and some may
not.
Or maybe my fears are unfounded?

Thanks

-GECKO

Reply to this Message

kony - 26 Jul 2008 02:27 GMT

>Prev posted in wrong group mouse slipped sorry
>
[quoted text clipped - 8 lines]
>
>-GECKO

The easiest way is to tell us about your hardware, and/or
look up the chipset specs yourself.

Reply to this Message

gecko - 26 Jul 2008 12:39 GMT

>The easiest way is to tell us about your hardware, and/or
>look up the chipset specs yourself.

Posted.
Thanks
-GECKO

Reply to this Message

Joel - 26 Jul 2008 03:59 GMT

> Prev posted in wrong group mouse slipped sorry
>
[quoted text clipped - 3 lines]
> actually running at USB2 speed? I fear that some may and some may
> not.

The easiest way to find out is looking at the MANUAL of your motherboard
to see what it says, or if it's somewhere around 3-4 years old then the
chance to be USB2 is very high, and 8 ports is kinda unusual to me (all
momboards I have have 4 USB2 ports) so it seems like yours is very new and
they may be USB2.

> Or maybe my fears are unfounded?

I can't tell how much fear you have at your end. And what good to fear
the unknown for?

> Thanks
>
> -GECKO

Reply to this Message

Paul - 26 Jul 2008 05:11 GMT

> Prev posted in wrong group mouse slipped sorry
>
[quoted text clipped - 8 lines]
>
> -GECKO

There are typical ways they're set up.

In terms of USB 1.1 capability, two ports are connected to one
logic block. If you saw four of the lower speed entries in
Device Manager, that would be enough to control eight ports.

On USB2, there can be one logic controller which hooks to all
eight ports. So when you see the "Enhanced" entry, it applies
to all the ports on the Southbridge.

Say I had, a four port PCI based USB card, and I also had USB
ports on my Southbridge (chipset) chip. And I looked in Device
Manager and saw two Enhanced entries. The exact text string
for both would be different. One Enhanced entry would correspond
to the Southbridge (controlling all of its eight ports), and the
other Enhanced entry would be for the PCI card (controlling its
four ports).

So it helps to know how many chips are involved, because an
entry in Device Manager likely won't span two chips.

Some of the recent Intel Southbridges have opted for two
USB2 logic blocks, spreading the ports between the two
blocks. The motherboard would likely have more than 8 USB
ports on it. I'd expect to see two Enhanced entries there.

So those are some possible Device Manager patterns.

For Intel chipsets, you can download tech documents from the
Intel site, and see how many logic blocks are used. Intel
even provides a diagram, showing how the ports are dynamically
bound to a logic block (USB1.1 or USB2 block).

For example, try figure 5-14 on PDF page 222 here. EHCI is
an Enhanced logic block. The little switches on each USB physical
port, flip the port between a USB1.1 logic block, and a USB2
logic block, according to the capabilities of the newly plugged
in USB external device. In Device Manager, this computer would
have two Enhanced entries, for the two EHCI blocks.

http://www.intel.com/design/chipsets/datashts/316972.htm

Paul

Reply to this Message

gecko - 26 Jul 2008 12:38 GMT

>There are typical ways they're set up.
>
[quoted text clipped - 34 lines]
>logic block, according to the capabilities of the newly plugged
>in USB external device. In Device Manager, this computer would

have two Enhanced entries, for the two EHCI blocks.

>http://www.intel.com/design/chipsets/datashts/316972.htm
>
> Paul

Thanks Paul. I will try to digest what you say above.
As I have said in earlier un-related posts, I have two machines.
I looked closely at both and this is what I see:
Machine 1 (XP)
-MachSpeed K8M8MSR2 mobo.
-Six physical USB ports on the back.
-Four USB ports are connected to one part of the mobo.
-Two USB ports are connected to different mobo header.

Machine 2 (VISTA)
-ASUS K8V SE Deluxe mobo.
-Eight physical USB ports on the back.
-Four USB ports are connected to one part of the mobo.
-Four USB ports are connected to different mobo header.

Strangely (to me), Device Manager on BOTH machines show identical
results:
Universal Serial Bus controllers
USB Root Hub
USB Root Hub
USB Root Hub
USB Root Hub
USB Root Hub
VIA Rev 5 or later USB Universal Host Controller
VIA Rev 5 or later USB Universal Host Controller
VIA Rev 5 or later USB Universal Host Controller
VIA Rev 5 or later USB Universal Host Controller
VIA Enhanced USB Controller

It bothers me that Device Managers show the same thing, despite the
fact that the two machine have different USB layouts. How can that
be? It is not obvious to me how to relate each Device Manager entry
to specific USB ports. Therefore, I was thinking some utility might
exist that would be more specific in that regard, and might even tell
me what ports are USB1 and what ones are USB2. But maybe they ALL are
now USB2?

-GECKO

Reply to this Message

Paul - 26 Jul 2008 14:19 GMT

>> There are typical ways they're set up.
>>
[quoted text clipped - 77 lines]
>
> -GECKO

K8V SE Deluxe has a VT8237R Southbridge. Some specs are here.

http://www.via.com.tw/en/products/chipsets/southbridge/vt8237/specs.jsp

"Support for 8 USB 2.0/1.1 ports"

So what is the difference between a motherboard with 8 ports and one
with 6 ports ? Two ports aren't wired to anything, and are just
sitting there idle on the chip.

Some points to ponder.

1) What you see in Device Manager is "logic blocks" and not ports.
Ports are not shown.

2) Ports are switchable between operating in a USB 1.1 mode and a USB2 mode.
They support both and are backward compatible. That is accomplished by
having a switch at the port, to either connect the port to a USB 1.1 logic
block or a USB 2.0 logic block.

And that is why you should have looked at PDF page 222 of the spec I pointed
out, as once you see the diagram, it makes a little more sense.

If you want to see what is going on at the port level, you need this.
UVCView first appeared on the Microsoft site, and is part of some SDK.
It was downloadable for a couple years, and then disappeared. I used
to point people to a copy on web.archive.org, but at least one person
had a problem with that copy (the last byte of the file is missing,
but that didn't prevent it from running on my computer). This copy
appears to be intact, and the file information matches the original
I got from Microsoft. (You could always download the web.archive.org
copy, and add 00 hex to the file with a hex editor. But I don't want
to make this harder than it has to be.) You compute the md5sum with a
program called md5sum, and it is handy to have a copy of that sitting
around as well. I use it for verifying the checksum on some Linux
downloads.

ftp://ftp.efo.ru/pub/ftdichip/Utilities/UVCView.x86.exe

File size is 167,232 bytes.
MD5sum is 93244d84d79314898e62d21cecc4ca5e

In this sample screen shot (from a precursor of the current version),
you can see a USB device connect to port 3. The port 3 entry is
part of a Root Hub that has six port entries, and that tells you
the device is running in USB2 mode. If the USB device instead had
appeared in one of the upper entries, where the Root Hub has only
two entries, then you'd know the device was running in USB 1.1 mode.

Note that there is one anomaly with that picture, and one of the
USB 1.1 Root Hubs is missing in the displayed image. It might be
present when the left hand pane scrolls down.

To make sense of the parameters in the right hand screen, you need
to go to usb.org and download a copy of the USB2 spec. You can
also google the parameter names, and get info that way.

Paul

Reply to this Message

gecko - 26 Jul 2008 16:04 GMT

>K8V SE Deluxe has a VT8237R Southbridge. Some specs are here.

My Everest verifies that you are correct.
But you knew that, :<)

>http://www.via.com.tw/en/products/chipsets/southbridge/vt8237/specs.jsp
>
[quoted text clipped - 52 lines]
>
> Paul

Reply to this Message

gecko - 26 Jul 2008 17:54 GMT

>So what is the difference between a motherboard with 8 ports and one
>with 6 ports ? Two ports aren't wired to anything, and are just
>sitting there idle on the chip.

Think so?

I just checked and both halves of one set of four are connected to the
mobo. The other four are mounted right on the mobo.

I dunno.

-GECKO

Reply to this Message

gecko - 26 Jul 2008 18:02 GMT

>So what is the difference between a motherboard with 8 ports and one
>with 6 ports ? Two ports aren't wired to anything, and are just
>sitting there idle on the chip.

I eat my words! I just checked further, and the mobo connected to
only 6 USB ports indeed has another USB header unused. There's the
other 2!

Sorry - I was wrong as usual.

-GECKO

Reply to this Message