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Participant
Participant
965 Views
Registered: ‎12-19-2018

Mig 7 series clock output inverted/swapped

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Dear Developers,

 

We are working with an Artix 7 (XC7A200T) and 2 DDR3 banks connected to it.

One of the banks is working ok, but on the 2nd bank we unfortunately swapped CK_P & CK_N on the PCB layout.

When using MIG with the "correct" CK polarity, it confirms the pinout is ok. Once we try to enter the wrong (but actual) pinout, pinout verification fails.

Its clearly a PCB design issue, but I wanted to understand if there is any option to get this design working.

 

What we've tried so far:

- MIG7 setup with correct pin assignment, then manually changed the pin assignment in the MIG constraints file

- different clocks from 300 to 400MHz

 

Any idea or suggestion is highly appreciated.

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Participant
Participant
946 Views
Registered: ‎02-06-2018

Open the implemented design in Vivado, trace the CK_P net back to the ODDR which is driving it, should look something like this:

 

Capture.PNG

Click on the ODDR cell properties and set IS_D1_INVERTED and IS_D2_INVERTED to 1'b1. That should invert your clock.

Hopefully it will not add any delay. Or you could re-route D1 to 1 and D2 to 0.

The couple of lines of TCL that this generates could be hooked into your flow using a post-route script.

Let us know if it works

View solution in original post

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Highlighted
Participant
Participant
947 Views
Registered: ‎02-06-2018

Open the implemented design in Vivado, trace the CK_P net back to the ODDR which is driving it, should look something like this:

 

Capture.PNG

Click on the ODDR cell properties and set IS_D1_INVERTED and IS_D2_INVERTED to 1'b1. That should invert your clock.

Hopefully it will not add any delay. Or you could re-route D1 to 1 and D2 to 0.

The couple of lines of TCL that this generates could be hooked into your flow using a post-route script.

Let us know if it works

View solution in original post

Highlighted
Participant
Participant
926 Views
Registered: ‎12-19-2018

Hi,

 

Absolutely awesome - this worked like a charm!

Thank you so much for the quick and good response.

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