USB Issue Troubleshooting

[ArunD]

[xilman]

[tnt]

I'm not exactly sure what people are still discussing here ...

AFAICT from the history of this thread, the issue has been diagnosed. The ULPI PHY sometimes comes out of reset in a weird state where it's not responsive despite being provided with a clean reset pulse. The design used the Xilinx recommended PHY and is connected properly so it _should_ work. Obviously it doesn't (or not reliably for some people) so the failure lies either with Xilinx's zynq doing weird stuff on the pin pre-boot or with the PHY behaving strangely sometimes, but at this point it really doesn't matter all that much.

Given that none of this is under software control, I don't see how a firmware upgrade or FPGA bitstream upgrade alone would do anything. The only solution seems to be to extend the reset pulse of the PHY about 100ms longer than the one from the PS (so that the FSBL has had time to properly configure the pins) and this will require some hw mod. The question is how to achieve that in the easiest way possible.

[ajtravis]

[ajtravis]

[tnt]

AFAIK you can use the porcupine to connect two boards together via the elinks ? There are 2 connectors for each PEC that can be used with standard 2mm pitch IDC cables.

[ajtravis]

[tnt]

[ajtravis]

[njpacoma]

Adding myself to the list of people having problems.

* Failure mode (sometimes or always?)
99% failure (I have gotten USB to work once with the headless and once with the HDMI configurations.)

* Headless/hdmi configuration
Both.

* FPGA/Linux/Ubuntu version being used
headless: Linux parallella 3.14.12-parallella-xilinx-g40a90c3 #1 SMP PREEMPT Fri Jan 23 22:01:51 CET 2015 armv7l armv7l armv7l GNU/Linux

* Fan used?
Yes.

* SKU#
P1601-DK03, SN 0010680

* Power supply used
Supplied with kit ordered from Amazon.

I have had my Parallella for less than 1 week. I have had the USB problem since day 1. I have tried many different setups and workarounds from the comments in this thread. While I am sufficiently interested in this system to use it headless, I am disappointed that this problem still exists without a real solution. A problem of this significance could really impact the acceptance and adoption of this very interesting and useful product.