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AR# 43711

Timing Analysis - What are Path Tracing Controls?


What are Path Tracing Controls (PTCs)?


Enabling Path Tracing Controls turns on analysis of latches/asynchronous signals in PERIOD and OFFSET or unconstrained path analysis.

  • reg_sr_o - Combinatorial asynchronous output path - combinatorial path through Flop
  • reg_sr_r - Reset Recovery Time. Please note that when enabling reg_sr_r, the reset recovery time will be given under the setup calculation for these paths, while the reset removal time will be given in the hold calculation for the path.
  • lat_d_q - combinatorial latch through D pin to Q output
  • lat_ce_q - combinatorial latch through GE pin to Q output

NOTE: Some PTCS are enabled by default, meaning that these paths will be enabled during timing analysis, but others should be enabled using the ENABLE constraint in the UCF (see the Constraints Guide).

Example: ENABLE = reg_sr_r;

For disabling a particular PTC, use theDISABLE constraint.

Timing Analyzer can also enable and disable individual PTCs when performing Post Route analysis.

The Constraints Guide has a complete list of allPTCs available.

AR# 43711
Date Created 02/21/2012
Last Updated 03/04/2013
Status Active
Type General Article
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