Potential Issue on PS_SRST# Signal (MicroZed)

Hi Mah,

Are you seeing a failure on your board? Looking at this circuit its been around since 2013. I havn't seen any failures resulting from it as of yet.

Thanks,
Josh

Hi Josh,

I am designing a custom board which is very similar to Microzed. I just asked it to know if it is a good design practice or not? Do you advise using a  level shifter (e.g a simple FET) or not?

Regards.

Hi Mah,

If what you stated above is true, it is not good design practice. I'll have to confirm the results myself in regards to the MicroZed. Yes a simple translator FET would be fine.

-Josh

Hi Josh,

Please let me know if you have confirmed my statements.

regards.

Hi,

We are facing similar situation and saw 3 microzed-10 board failing. The issue is board resets itself, while debugging we saw that the PS_SRST# signal is going low. It keeps low until it is power cycled. Once its power cycled the board works for some time, then it  resets again, PS_SRST# signal is going low.

PS_SRST# signal is pulled up at two places: one through R64 to 1.8V and through internal pull-up of flash U7 to 3.3V. This seems to have damaged U19 when JTAG_RST# is driven low. When we removed U19 the board seems to be working fine.

Any inputs ?

Thanks

dkk

Hi dkk,

Just to get some background, are you seeing this on 3 of 3 (all of your) boards? Are you using a custom carrier card, an Avnet Carrier Card, or operating the MicroZed standalone? Im wondering how I can replicate this failure on my end.

-Josh

Hi Josh,

Thanks for the reply.

We are using a custom built carrier card. We are seeing this issue when its used with carrier card as well as in standalone mode. These failed boards are MicroZed-10. The failure is random. In one of the boards we are seeing the failure at a more frequent rate , after switching on it will fail with in a couple of minutes. In this board we removed U7 and it is now working without any issue.

Also one thing we have noticed is that the failure occurred  in boards in which we have used Xilinx Platform USB Cable. Also it takes sometime before which the board will start to fail. The board I have mentioned above worked for around one month before it started to fail.

You can try replicating the issue using a Platform USB Cable, I am not sure whether this is causing the problem. While analyzing the microzed schematic we could'nt understand whether there is an issue.

Thanks

Hi Josh,

Any updates

Hi DDK,

Can you please contact your local Avnet FAE for support on this issue? This would be your next step in getting support.

Just to follow up for some more information.

Is the board being placed in an ESD environment?

In the boards that are experiencing issues, have they all been exposed to your custom carrier card? (im wondering if the carrier could potentially be damaging the Microzed SOM which causes it to fail in standalone)

What OS are you running?

What percentage of your boards are you seeing failures on?

-Josh

Hi Josh,

Thanks for the reply.

I will try for local FAE support, don't know how successful it will be!! Is there any other kind of support possible.

I don't think its an ESD issue, as the failure is same in all boards.

The MicroZed-10 boards which have failed are used with one type of carrier card, but in all of them the Xilinx USB Platform cable has been used when plugged to the carrier card.

Also MicroZed-20 boards which were used with another carrier card, in which the JTAG has not been used doesn't have any problem.

In the failed board there is no OS, we are using firmware only.

So far we have seen failure in 3 MicroZed boards out of 4.

Thanks

dkk