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TX tuning failed for custom board

Question asked by gensysco on Jan 18, 2017
Latest reply on Jan 27, 2017 by sripad



We have a custom board with AD9361 connected to another custom board with Zynq on it. I have ported the non-OS software and HDL cores onto the Zynq with some additional logic in the RX chain such as windowing and detectors. When I run the sotfware, during the digital interface calibration i.e., ad9631_dig_tune, the RX tuning passes but the TX fails with the message "TX tuning failed".

I have tried this modified HDL and non-OS solution on the standard zedboard-fmcomms4 (with AD9364) setup and everything works fine. Can someone help me in answering the below questions and/or suggest some debugging start-points?


(1) The TX and RX LVDS lines are routed in the following stackup. We are able to successfully tune the RX, but TX tuning is failing. Does the stack up shown be a reason for this ?
      L3 - PWR Plane
      L4 - TX LVDS
      L5 - GND
      L6 - RX LVDS
      L7 - GND
(2) How are the TX LVDS lines terminated ? I assume they are terminated internally in AD9361. Is there a software bit to enable these terminations
Any help highly appreciated!