TimeQuest set_multicycle_path Command
By default, the TimeQuest analyzer uses a single-cycle analysis. When analyzing a path, the setup launch and latch edge times are determined by finding the closest two active edges in the respective waveforms. For a hold analysis, the timing analyzer analyzes the path against two timing conditions for every possible setup relationship (not just the worst-case). Therefore, the hold launch and latch times may be completely unrelated to the setup launch and latch edges.A multicycle constraint relaxes setup or hold relationships by the specified number of clock cycles based on the source (-start) or destination (-end) clock. An end multicycle constraint of 2 extends the worst-case setup latch edge by one destination clock period.
Hold multicycle constraints are based on the default hold position (the default value is 0). An end hold multicycle constraint of 1 effectively subtracts one destination clock period from the default hold latch edge. You can use the set_multicycle_path command to specify the multicycle constraints in the design. The following list shows the set_multicycle_path command including the available options:
set_multicycle_path
[-setup | -hold]
[-start | -end]
[-from <from list>]
[-to <to list>]
[-thru <thru list>]
<path multiplier>
Table 1 describes the options for the set_multicycle_path command.
Table 1. Options Description for set_false_path Command
When the objects are timing nodes, the multicycle constraint only applies to the path between the two nodes. When an object is a clock, the multicycle constraint applies to all paths where the source node (for - from) or destination node (for -to) is clocked by the clock.
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