AR #32543 - 11.1 Timing - Incorrect clock analysis after inverting my clock with a BUFIO2 or an INV
11.1 Timing - Incorrect clock analysis after inverting my clock with a BUFIO2 or an INV
| AR# | 32543 |
| Part | SW-Timing Analyzer/TRCE |
| Last Modified | 2009-06-05 00:00:00.0 |
| Status | Active |
| Keywords | local inversion, wrong, analyze, analyses, inverted, 180, degree |
Description
Keywords: local inversion, wrong, analyze, analyses, inverted, 180, degree
Timing analysis is being performed on an incorrect clock edge. My design is using an INV or a BUFIO2 to perform the clock inversion.
How can I correct the analysis?
Solution
When using logic such as a LUT (INV) or even a BUFIO2 to invert a clock, the timing engine has no indication that the clock was inverted. The inverting components are viewed as combinatorial logic, not clock-modifying blocks.To correct this issue, use local inversion or a clock-modifying block to invert the clock.
DCM, DLL, PLL, BUFR, PMCD, and MMCM components are considered to be clock-modifying blocks.