AR# 38550: Virtex-6 GTX and Spartan-6 GTP Transceivers - How do I enable "lock-to-reference" mode?
Virtex-6 GTX and Spartan-6 GTP Transceivers - How do I enable "lock-to-reference" mode?
Previous Xilinx Serial Transceivers allowed for a "lock-to-reference" mode, which would force the CDR to lock to the reference clock and not track the incoming data. Do the Virtex-6 GTX or Spartan-6 GTP Transceivers have this functionality?
You can set both the Virtex-6 GTX and Spartan-6 GTP Transceivers so that the CDR is locked to the reference clock rather than the incoming data, which is the case when oversampling the incoming data. As such, the values for PMA_RX_CFG that correspond to oversampling can be used for lock-to-reference mode: