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bhavanithya
Adventurer
Adventurer
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Registered: ‎06-04-2019

MIG Cal Fail at Read Per-Bit Deskew step

Hello,

I am having a design which is running on a custom board with part XCZU28DR-2FFVG1517E and with PL DDR4 CT4G4SFS824A.C8FF, 4gb, 2400 Mb/s SODIMM 1.2v CL17. External reference clock is set through petalinux (100MHz).

I am getting MIG Calibration error as you can see below,mig_cal.png

What does the message "No valid data found for a given bit in the nibble when running the de-skew pattern" means? When does this happen?

Weird part is the MIG calibration is successful without any error for the same design on another custom board with the same DDR type. What could be the reason for this behavior?

I also attached the MIG core properties.

 

Thanks,
Bhavanithya Thiraviaraja
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bhavanithya
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Registered: ‎06-04-2019

An update on my debug,

I found that the error occurs Rank0, Byte1, Nibble 2, bit 1 using the report generated.

And here is the ILA debug signals from DDR4 IP core

bhavanithya_0-1603199843881.png

I compared with the screenshot of debug signals from a working MIG from the Xilinx debug document, they seem the same to me but I can be wrong. I am not sure what the problem is.

https://www.xilinx.com/support/answers/60305.html

Thanks,
Bhavanithya Thiraviaraja
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kren
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Registered: ‎08-21-2007

Please compare the working the MIG pinouts are exactly the same. Are the MIG IP settings totally the same?

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bhavanithya
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Registered: ‎06-04-2019

Hello Kren,
Yes the IP settings and pinout is exactly the same. We use the same bit, hdf and petalinux files for both the boards.

A further update on the debug,
We also have another board (call this a new board) with CT4G4SFS824A.C4FB DDR SODIMM. This has the same configuration as the other SODIMM, CT4G4SFS824A.C8FF (mentioned above). So what I tried is to test the same design with the same MIG IP settings (but with different PS DDR settings) on this new board with both the SODIMMs. MIG Calibration is successful for both the cases.

What could be then the reason for the MIG calibration error with the other board. Could there be some hardware problem? If so how can I debug it?
Thanks,
Bhavanithya Thiraviaraja
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