Xilinx 1000BASE-X Manuel D’Utilisation

UG155 March 24, 2008

Appendix F: Debugging Guide

RocketIO Transceiver Specific Checks

Perform these additional checks when using a RocketIO transceiver: 

•

Directly monitor the following ports of the RocketIO by attaching error counters to 
them, or by triggering on them using Chipscope or an external logic analyzer.

RXDISPERR

RXNOTINTABLE

These signals should not be asserted over the duration of a few seconds, minutes or 
even hours. If they are frequently asserted, it may indicate a problem with the 
RocketIO. Consult 

 for debugging RocketIO issues.

•

Place the RocketIO into parallel or serial loopback. 

♦

If the core exhibits correct operation in RocketIO serial loopback, but not when 
loopback is performed via an optical cable, it may indicate a faulty optical 
module.

♦

If the core exhibits correct operation in RocketIO parallel loopback but not in 
serial loopback, this may indicate a RocketIO problem. See 

 

for details.

•

A mild form of bit error rate may be solved by adjusting the transmitter 
TX_PREEMPHASIS

, TX_DIFF_CTRL and TERMINATION_IMP attributes of the 

RocketIO.

•

For Virtex-II Pro RocketIO only, check that the SERDES alignment logic is properly 
constrained to be placed near the RocketIO. See the Virtex-II Pro RocketIO Transceiver 
User Guide for more information. This constraint is not automatically adjusted for 
different RocketIO locations.