[SOLVED] set_false_path for static input

[scscsc]

Hi,

I have a circuit with two asynchronous clocks, one low frequency clock SCK is for programming the coefficients COEF[19..0] in the instance ISPI at the startup phase. Once the programming process is finished, COEF[19..0] doesnot change any more, the other instance IFILTER cadenced by the other clock DIV takes the values in ISPI/COEF[19..0] and starts to work.

my question is in my file .sdc how can I tell the tool that COEF[19..0] is a static input for IFILTER? because if not, there is a huge negative slack and the tool tries hard to minimize the delay. Here is my script, it seems that i used set_false_path in a wrong way

create_clock [get_pins IDCO/DIV] -name DIV -period 3 -waveform {0 1.5}
create_clock [get_ports RESNODE] -name reset_ideal -period 3 -waveform {0 1.5}
create_clock [get_ports SDE] -name en_node_ideal -period 1000 -waveform {0 500}
create_clock [get_ports SCK] -name sck_ideal -period 100 -waveform {0 50}
set_false_path -from [get_pins ISPI/COEF] -to [get_nets IFILTER/*]

Thanks

 

[rca]

you could also used "set_case_analysis"

set_false_path -from [get_pins ISPI/COEF[*]], you do not need -to.with this command you declare all paths who come from are declare to false.

 

[scscsc]

set_case_analysis works well, thanks rca!