usb ports

  ponytail 20:48 07 Jan 2008

Have just fitted a new case and motherboard the case had two usb ports at the top and they work fine but the four from the motherboard do not worl and all the connections seem fine.ny ideas anyoneY

  Jim_F 08:39 08 Jan 2008

I can think of two possibilities:

1) The hubs are not enabled in bios

2) The header pinouts are not the same (not applicable if these are actually on the board itself)
click here

Also beware that some serial/firewire headers look just like USB ones !

If you have the USB sockets on brackets then unles they were supplied with the board this would be the cause.

Fortunately the colours are standard so you can compare these against your motherboard manual.

One tip with testing. I always test with a passive device such as a mouse as this reduces the risk of damage if you have made a mistake.

  wotbus@ 08:49 08 Jan 2008

Have you installed the drivers?
Usually USB support comes with the mobo disc.
Look in Device Manager for a yeller question mark. If you find any against anything as well as USB - right click it and select Properties then Update Driver.
You should get it sorted easily so don't worry too much ;-)

  DieSse 11:12 08 Jan 2008

"I always test with a passive device such as a mouse as this reduces the risk of damage if you have made a mistake."

Just a comment - How is a mouse a passive device?. It uses power from the USB, and feeds data in.

  DieSse 11:13 08 Jan 2008

".. but the four from the motherboard .."

Do you mean the four ON the motherboard, or four on a bracket fed via a cable FROM the motherboard?

  Jim_F 00:16 09 Jan 2008

Hi DieSse,

I meant passive as in it only interacts with the USB connection - it dosen't have a PSU and so prod 5v into what potentially could be a data connection. Maybe 'bus-powered' would be a better description ?

  DieSse 00:23 09 Jan 2008

Hi Jim_F

There aren't any devices that put power back into a USB port - the danger is the lines coming from the motherboard may get mixed up and blow the attached device. You can't stop that by using different attached devices.

It may however be good to use a low-cost device if you're worried about USB miswiring!

  DieSse 00:24 09 Jan 2008

"...and blow the attached device."

and/or the motherboard!

  Jim_F 00:48 09 Jan 2008

Hello again DieSse,

On a powered device the data connections will carry voltages so I don't completely agree but I do agree that there is always an element of risk with any miswired connection.

The general advice - use a bus powered mouse rather than a USB HDD with its own PSU to test with has worked well for me. If we had a more standardised approach to USB headers that would be better of course !

  DieSse 01:00 09 Jan 2008

No, Jim - data connections carry data - that's all. Though of course the data itself is a varying voltage signal :-

"Transmitted signal levels are 0.0–0.3 volts for low and 2.8–3.6 volts for high in Full Speed and Low Speed modes, and +-400mV in High Speed (HS) mode."

These data signal levels are irrespective of whether they come from a motherboard, a hub, a device, and of whether the device or hub is powered or not. This has to be the case or it wouldn't be recognised as data.

The voltages (power) associated with USB is on two other cables, which won't be mixed up inside an attached device.

  Jim_F 09:45 09 Jan 2008

I'm afraid I don't agree DieSse,

On a wired connection all connections will carry a voltage (or 0v) - and typically a USB 1.1 device will have a pull-up of 3-3.6 volts with respect to the Ov of that device. This can look higher if the two devices don't have a common Ov connection !

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