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Observer
Observer
273 Views
Registered: ‎07-02-2019

Aurora 8B10B link cannot connect sometimes

I included one Aurora 8b10b IP on two FPGA boards' firmware.

When these two FPGA boards' GTP transceivers are connected, both firmware should have "channel_up" HIGH automatically, which means the link is connected. As shown in the IP manual:

Capture.PNG

The sequence of Aurora IP's reset and gt_reset I applied is:

reset-0, gt_reset-0

delay
reset-1, gt_reset-0

delay
reset-1, gt_reset-1

delay
reset-1, gt_reset-0

delay
reset-0, gt_reset-0

Sometimes "channel_up" doesn't go HIGH after this sequence of reset and gt_reset, but if I apply this sequence one more time, channel_up will recover.

The possibility of first time success is ~2/3.

 

Thank you for any replies.

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5 Replies
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Xilinx Employee
Xilinx Employee
258 Views
Registered: ‎08-13-2007

Have you used IBERT with your GTP settings to check your link performance/BER/etc.?

Cheers,

bt

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Observer
Observer
254 Views
Registered: ‎07-02-2019

Yes, IBERT test is pretty strange too.

With PMA loopback mode, the IBERT tests pass, both in near-end and far-end.

But with PCS loopback mode, the link shows connected, the link transmit speed is right, but with a lot of transmission errors.

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Moderator
Moderator
180 Views
Registered: ‎01-10-2019

Hi @jiongsi ,

Are you follow Power On reset Sequence ?

 

Thanks,
Rahul Khatri
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Observer
Observer
165 Views
Registered: ‎07-02-2019

I tested the power voltage to the GT bank after powered on, it looks stable and no noise.

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Moderator
Moderator
160 Views
Registered: ‎07-30-2007

Did you test it at the time of failure?  If so, see what the Eye Scan looks like.




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