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发表于 2011-1-22 16:47:52
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回复 47# iceplanet
http://www.cadence.com/Community/blogs/ld/archive/2008/12/16/ius82-support-for-create-isolation-rule-no-condition.aspx
New Functionality for Low Power Simulation
By John Rodriguez on December 16, 2008Comments(0)Filed under: Logic Design, IUS82, low power simulation
The IUS82 release has added in some great new functionality for low power simulation.
Oneof these updates is that beginning with IUS82 simulation now supports a-no_condition argument for create_isolation_rule. In previous versionsthere was no way to force the simulator to isolate a domain and alsopowerdown that domain with the same signal. If something like this wastried inconsistent results would occur because of the possibility of arace occuring between the enabling of the isolation and the corruptionof the domain. Consequently it was required that separate signalscontrol the isolation and powering down of a domain. Users wereencouraged to trigger the isolation, run some time, then trigger thepower down, and then do the opposite when powering back up. Essengtially some finite time was needed between the isolation and thepowerdown to insure that a race would not occur.
Beginning withIUS82, with the use of the -no_condition argument there is no longer arequirement that a separate signal control the isolation and powerdownof a domain. Users wishing to trigger isolation and powerdown on thesame signal can do so by using the -no_condition argument tocreate_isolation_rule as follows:
create_power_domain -name PD_switchable \
-instances path/to/inst \
-shutoff_condition {u_pmc/power_control_en}
create_isolation_rule -name ISO_low \
-from PD_switchable \
-no_condition \
-isolation_output low
Notethat in the above coding the use of the no_condition argument tocreate_isolation_rule. When used as above whenever the domainassociated with the isolation rule is powered down, isolation willoccur prior to corruption of the domain. Conversely when the domain istriggered back on the corruption is released and then the isolation isreleased.
This functionality is currently available in IUS82 as well as CLP81 and will be supported in RC Q1/2009. |
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