We have a Virtex7 FPGA talks with TI DSP on board. The data link is about 200Mhz. We have delivered multiple boards before and data link worked good at low temp (<zero C) . But for the recent boards, data link fails at low temp and data received by TI DSP is all zero. Data link works fine at normal (25C) and high temp (70C).
Any idea where to start and what could be the issue?