AR# 60836: Aurora 8B10B - Vivado 2014.2 or earlier - GTP and GTH - Production reset DRP sequence could get in hung state that requires reconfiguration to recover
Aurora 8B10B - Vivado 2014.2 or earlier - GTP and GTH - Production reset DRP sequence could get in hung state that requires reconfiguration to recover
Aurora 8B10B v10.2 and earlier, when targeted for GTPE2 and GTHE2 execute a series of DRP operations as per the 7 Series GTH and GTP Production RX reset sequence requirements covered in (Xilinx Answer 53779) and (Xilinx Answer 53561).
These operations are:
(a) Read the DRP value for the internal data width. (b) Write a DRP value (Force to 16-bit internal data width). (c) Write the DRP value read in (a) to restore the original internal data width.
If the module receives another reset from the user after (b) but before (c) then on the next iteration it will read a 16-bit internal data width in step (a), and thus at the end of the sequence will restore a 16-bit internal data width.
This means that the transceiver is now permanently in 16-bit mode and the only way to recover is to re-program the device.
All of the updates mentioned in the GT wizard Answer record (Xilinx Answer 60489) also apply to Aurora 8B10B.
This issue will be fixed in the Aurora 8B10B core released with VIVADO 2014.3