set_timing_derate (::quartus::sdc_ext)
The following table displays information for the set_timing_derate Tcl command:
Tcl Package and Version |
Belongs to ::quartus::sdc_ext 2.0 |
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Syntax | set_timing_derate [-h | -help] [-long_help] [-cell_delay] [-early] [-late] [-net_delay] [-operating_conditions <operating_conditions> ] <derate_value> [ <cells> ] | |||
Arguments | -h | -help | Short help | ||
-long_help | Long help with examples and possible return values | |||
-cell_delay | Specifies that derating factors are only to apply to cell delays | |||
-early | Specifies the minimum derating factor. This factor specifies how early the signal can arrive | |||
-late | Specifies the maximum derating factor. This factor specifies how late the signal can arrive | |||
-net_delay | Specifies that derating factors are only to apply to net delays | |||
-operating_conditions <operating_conditions> | Operating conditions Tcl object | |||
<derate_value> | Timing derate value | |||
<cells> | List of cell type objects | |||
Description |
Sets the global derate factors for the current design. The maxmimum and minimum delays of all timing arcs in the design are multiplied by the factors specified with the -late and -early options respectively. Only positive derate factors are allowed. If neither the -cell_delay nor -net_delay option is used, the derating factors apply to both cell and net delays. For net delay derates, the derate factor is applied to nets driven by matching cells. Specifying a derate value of less than 1.0 for the -late option or a derate value of greater than 1.0 for the -early option reduces delay pessimisim, which might lead to optimistic results from timing analysis. The effect of set_timing_derate command is deferred until the next time update_timing_netlist is called. To reset derate factors to original values, use the reset_timing_derate command. This assignment is for timing analysis only, and is not considered during timing-driven compilation. |
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Example Usage |
set_timing_derate -early 0.9 [get_cells *] set_timing_derate -late 1.1 [get_cells *] |
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Return Value | Code Name | Code | String Return | |
TCL_OK | 0 | INFO: Operation successful | ||
TCL_ERROR | 1 | ERROR: Option -<string> has illegal value: <string>. Specify a legal option value. | ||
TCL_ERROR | 1 | ERROR: Timing netlist does not exist. Use create_timing_netlist to create a timing netlist. |