AR# 38141: CoolRunner-II Timing - Bi-directional signals can have the wrong results in Timing Analyser
AR# 38141
CoolRunner-II Timing - Bi-directional signals can have the wrong results in Timing Analyser
Description
When I look at the timing report for a Bi-Directional signal it appears to have passed, but when the delays are calculated it actually has failed. Why is the failure not highlighted?
Solution
This is a known issue. Following is an example of an incorrectly reported path:
The delay is listed as 3.5nS which gives a slack of 6.5nS, but the path is actually 5.6 + 2.3 + 3.5 = 11.4ns, so the constraint should have failed with a slack of -1.4nS.
To work around this issue,use the ASCII report (which correctly analyzes). The ASCII report can be generated by running the following in the command line: