BBxm Rev C and Rev C1 USB: not the same behaviour

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1

Hi,

I’d like to point out something really weird happening on bb xms.

I have a bbXm Rev C and a C1 both using the demo images provided on the elinux.org.

I have a 3G modem that i need to provide an internet connection. The 3G modem board has a ESD protectio chip which we need to remove to make the kernel enumerate the device (bbxm REV C). On the rev c1 I do not need to remove the ESD protection to make the kernel enumerate the device.

I checked on the bb website the changes made from rev c to rev c1. It says: “Only one change was made for this revision. The pads on the expansion headers wee beefed up to address some issues we were seeing where there was a disconnect between the etch and the pads inside the PCBs. The schematic and bill of materials remain the same as revision C.”

I don’t get how this would make any difference (beefing up in consolidating right?)… So I tried to connect the device on another USB port on the REVC1… and it doesn’t get enumerated “hub 1-2:1.0: unable to enumerate USB device on port 5”.

2

Beefing up mean adding copper.Making the connection between the etch and the pads stronger. It does not mean consolidating.

Gerald

3

And what is the etch?

Le 20/12/2012 15:29, Gerald Coley a �crit :

4

That is the pieces of copper on the board that provides the electrical connection between components on the printed circuit board, where are the components are soldered onto. The board is made out of fiberglass and has multiple layers each containing etch that are glued together to make the board.The change made was to where the etch connected to the pad, the hole in the board where the connector pins are soldered stronger t prevent breakage when exposed to high force when plugging in boards to the connector.

This cannot have caused the issue you are seeing.

Gerald

5

Ok thank you.

TIf it should not be the source of the problem then something else must have been changed on the board right? Could components tolerances be the source of the issue?

Le 20/12/2012 15:38, Gerald Coley a �crit :