Parallella Community

Hi, I've just received my Parallella board... I've noted that some component are missing (U17, U13, SW2) (at least). By comparing with the schematics, it appear that these components are related to USB and Reset. Because It seems that documentation are not up to date, I'm not sure these components are really requiered.

The missing components (at least) are:

Name : U17
Reference : USB3320
Manufacturer : Microchip
Designation : USB transceiver
Note : It is used by the USB-OTG

Name : U13
Reference : MIC2025-1
Manufacturer : Micrel
Designation : Power distribution switch
Note : It is used around the USB peripheral

Name : SW2
Reference :
Manufacturer :
Designation :
Note : This is a switch to manually reset the board

The board is referenced as:
SKU P1602-01
SN 0012523

The box is referenced as:
819-4702
P1602-DK02


So, my question is: Are there anybody who has a board without these components and where the USB is still working?????

Thanks...

Regards,
Gilles

Hi Gilles,

Some of the older boards had additional component positions populated and worked fine, but IIRC it was easier to cause damage through use of a non-compliant USB hub.

Regards,

Andrew

Hi Andrew, thanks for your reply.

So, if I well understand:
-> USB-OTG is unavailable and the J7 connector can only be used to power up the board
-> USB-Peripheral (J6) can only works as slave (no internal board VBUS)

...is that right?


Thanks

Regards,
Gilles

Hi,
There's some history here. The items are not so much 'missing' as removed in later revisions of the boards.
The USB connector next to the Ethernet socket never worked properly as a USB port. The (useless) U17 chip has been removed. The USB socket is now only used as an alternative power connector, instead of the barrel socket, as you rightly guessed.
Note, on the micro server version, the other USB (and HDMI) chip and socket are also removed.

The latest boards include a large square heatsink which completely covers the area where the reset switch is, making it inaccessible/useless. It too has been removed in later versions. If you can see that area of the board then it means you have yet to fit the heatsink. I'd do that ASAP if I was you.

Cheers,

Hi, thank you for your reply....It was very usefull to understand where it come from .

And.... yes... I will follow your advice and fix the heatsink asap...

Regards,
Gilles.