Altera SDC and TimeQuest API Manual do Utilizador descarregar pdf (Página 88)

2–78 Chapter 2: SDC and TimeQuest API Package and Commands

sta

SDC and TimeQuest API Reference Manual © December 2009 Altera Corporation

enable_ccpp_removal

Usage

enable_ccpp_removal [-depth <depth>] [-off] [-on]

Options

-depth <depth>: maximum clock tree depth for cppp removal

-off: Disable this setting.

-on: Enable this setting.

Description

Enables (or disables) common clock path pessimism (CCPP) removal during slack computation. CCPP

removal can improve timing results by removing min/max delay differences from common portions of

clock paths. Enabling CCPP removal increases the time required to perform timing analysis.

When specified, the optional depth parameter limits the clock tree depth used for CCPP removal. This is

generally not applicable to FPGA compilations where the clock tree is fixed, but for large HardCopy

designs with potentially deep synthesized clock trees this can reduce outlier run time.

When not specified, or when specified with a value of 0, the complete clock tree is used for CCPP removal

(i.e. full clock-tree depth).

Example

project_open top

create_timing_netlist

read_sdc

# Report timing without CCPP removal

report_timing

# Enable CCPP removal and re-report timing.

enable_ccpp_removal

report_timing

delete_timing_netlist

project_close

1 2 ... 83 84 85 86 87 88 89 90 91 92 93 ... 167 168

Sem comentários

Altera SDC and TimeQuest API Manual do Utilizador Página 88