I need your help in length tuning a group of nets!
Design is a DDR2 board, I am trying to tune each DQS group. Each group contain an 8-bit single ended data lines and a differential pair. Interactive routing and length tuning of single ended section is fine, but the diff pair fails. I used following rule in the "Matched Net Length" section:
InNet('DDR2_D0') OR InNet('DDR2_D1') OR InNet('DDR2_D2') OR InNet('DDR2_D3') OR InNet('DDR2_D4') OR InNet('DDR2_D5') OR InNet('DDR2_D6') OR InNet('DDR2_D7') OR InNet('DDR2_DM0')OR (IsDifferentialPair And (Name = 'DDR2_DQS0'))
Problem is that selecting "Diff pair Interactive Length Tune" from Tools menu and clicking the diff pair, software is unable to calculate the target length for diff pairs.
- Do you have any idea where is the problem?
- Is the rule definition correct?
- Do I need to define a separate rule for diff pair? If so, how to tell the new group to use 'DDR2_D*' target length as a target for diff pair too?