AR# 17414: 14.x Timing - Can I modify the Phase Shift on a DCM in FPGA Editor and have it affect timing analysis?
14.x Timing - Can I modify the Phase Shift on a DCM in FPGA Editor and have it affect timing analysis?
I modified the DCM Phase Shift value in FPGA Editor and saved the new NCD and PCF files. When I tried to analyze the timing with the new NCD and PCF files, I anticipated changes in the timing numbers. However, Timing Analyzer did not show any changes for my constraints.
FPGA Editor is correctly changing the PHASE_SHIFT value in the NCD file, and this change will be reflected in hardware. However, it is important to note that the FPGA Editor does not go back and modify the requirements on timing constraints in the PCF.
To work around this issue, you can modify the PHASE_SHIFT value in the UCF and then re-run the tools. As a result, the NCD and the PCF files will constrain the correct PHASE_SHIFT value, and hardware and timing analysis will match.