USB Interface

[ross2]

Posted on August 10, 2004 at 06:50

USB Interface

[ross2]

Posted on August 05, 2004 at 12:18

On the STR10 Eval schematics there is a USBUF01W6 filter/buffer on the USB lines. From a quick look at the parts datasheet it seems to be connected with the in and outs the wrong way around.

Is it just me, a mistake or is there a reason ?

[mohamed23]

Posted on August 06, 2004 at 08:44

Hi RBUK,

The datasheet in not wrong, but here it is a misunderstanding about

In/Out. In terms of USB we talk about IN and OUT transferts

The reference in USB is always the Host PC ,

so :

OUT : Data from Host to Device

IN : Data from Device to Host

We can see that the PinOuts of the USBUF01W6 ( ST emi filter and line termination for USB Upstream ports) in datasheet are correct since STR71x device is a Full Speed one.

D+ device connected to 6 / D+ Host connected to 1

D- device conncted to 4 / D- Host connected to 3

Cheers,

[ This message was edited by: Rave on 06-08-2004 12:16 ]

[ross2]

Posted on August 06, 2004 at 09:39

Thanks for the reply, but I still don't quite get this.

I am looking at at using the EVAL board schematics to make a test board.

Looking at the USBUF01W6 data sheet Fig A1 or A2, for a full speed connection, the function / peripheral side of D+ shows that it is connected to D4 (pin6) of the device.

On the Eval schematics there is a Type B connector, the board is the function side of the link, and D+(DP) from the connector is connected to pin1(D1) of the USBUF01W6, shouldn't this be D4(pin6) side ?

[mohamed23]

Posted on August 06, 2004 at 15:54

Hi,

You are right, It is a mistake on The Eval Board Shematics...

But anyway I think that It is not a good reference to be adopted

if you want to have a Full Device, In this case you should

be able to manage the Pull-Up of D+ with a GPIO.

Regards,

[ross2]

Posted on August 10, 2004 at 06:50

Thanks !