mini USB pinout

Hi,

I'm wondering what the pinout of the mini USB connector is? I googled
for this and found the following 2 standards:
Pin 1 - VBUS
Pin 2 - D-
Pin 3 - D+
Pin 4 - unconnected
Pin 5 - GND

Pin 1 - VBUS
Pin 2 - D-
Pin 3 - D+
Pin 4 - connected to pin 5
Pin 5 - GND

So is Pin 4 unconnected or grounded? I tried probing the mini-USB
connector of a 2.5" HDD enclosure that I have with a multimeter and pin
4 is apparently grounded as well. Does it even matter? Also, is the
shell also grounded directly or does it have any capacitors?

Thanks!

galapogos <goister@gmail.com> wrote:

> I'm wondering what the pinout of the mini USB connector is?

There's more than just one mini USB connector.

> I googled for this and found the following 2 standards:
> Pin 1 - VBUS
> Pin 2 - D-
> Pin 3 - D+
> Pin 4 - unconnected
> Pin 5 - GND

> Pin 1 - VBUS
> Pin 2 - D-
> Pin 3 - D+
> Pin 4 - connected to pin 5
> Pin 5 - GND

> So is Pin 4 unconnected or grounded?

You see both approaches.

> I tried probing the mini-USB connector of a 2.5" HDD enclosure that I have with
> a multimeter and pin 4 is apparently grounded as well. Does it even matter?

Nope, doesnt matter if you ground an unconnected pin.

> Also, is the shell also grounded directly

Usually not, but it sometimes is.

> or does it have any capacitors?

Varys.

galapogos wrote:
> Hi,
>
> I'm wondering what the pinout of the mini USB connector is? I googled
> for this and found the following 2 standards:
> Pin 1 - VBUS
> Pin 2 - D-
> Pin 3 - D+
> Pin 4 - unconnected
> Pin 5 - GND
>
> Pin 1 - VBUS
> Pin 2 - D-
> Pin 3 - D+
> Pin 4 - connected to pin 5
> Pin 5 - GND
>
> So is Pin 4 unconnected or grounded? I tried probing the mini-USB
> connector of a 2.5" HDD enclosure that I have with a multimeter and pin
> 4 is apparently grounded as well. Does it even matter? Also, is the
> shell also grounded directly or does it have any capacitors?
>
> Thanks!
>

http://www.zytrax.com/tech/pc/serial.html

This article says the extra pin serves as an ID function.
Part of USB OTG and defining initial roles for the two
devices at the ends of the USB cable.

http://www.maxim-ic.com/appnotes.cfm...=1822&CMP=WP-3

( Link found on http://en.wikipedia.org/wiki/USB_OTG )

Paul