UmTRX issue

Thomas Tsou ttsou at vt.edu
Wed Oct 31 19:00:57 UTC 2012


On Tue, Oct 30, 2012 at 11:39 PM, Alexander Chemeris
<alexander.chemeris at gmail.com> wrote:
> Could you please describe symptoms which you observe on your UmTRX? We
> have to figure out the reason for the improper behavior and if this is
> a manufacturing issue - make sure this won't happen for the next
> batch.

I was going to retest, I can't do that until later tonight.

Anyhow, I ran into some Ethernet issues when I first booted the
UmTRXv2 last week. Board powers up and FPGA loads fine from JTAG with
recent .bit image, but I was not able to get network connectivity. I
noted the following observations only when Ethernet cable is plugged
in. After brief discussions with Alexander, it seems that this
behavior is not expected.

LED 'I' is on constantly but blinks every few seconds
'LED4' blinks every few seconds
Voltage at 1.2V regulator drops to .8V when blinking occurs

Also, the above behavior is sometimes present before the FPGA load if
Ethernet is connected.

I use the following power supply at 12V; current is not limited.

  http://www.atecorp.com/Equipment/tek/ps280.asp

That's all I have right now from some earlier notes. Any thoughts?

  Thomas




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