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how to balance the skew of FFs that used to divide clock?

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starmx

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some FFs are used as a counter to divide the master clock,for example,reg clock[N:0],clock[0] is the divided_by_2 clock...
but the CP pin of clock[N:0] are not balanced by Astro by default.
the document said:"By default, CTS will not balance the skew of FFs that cross clock domains."

so here's the problem,the skew between clock[N:0] is large ,the largest skew is between clock[3] and clock [5], >3ns!, then the counter can't work.

how to blance the skew between FFs clock[N:0]?
not to balance with other FF sinks,just between the CP pin of FFs clock[N:0],so the counter can work

thanks
 

i tried the dbdefinesyncpin command:
"dbDefineSyncPin (geGetEditCell) "u_digital1_top/u_clock/dutcks/ck_reg_0" '(("CPN" "nonInvertFall" (3.3 3.3)))
"

but report
"syntax dbDefineSyncPin CellID InstName Items"
is this a error imformation?
how to use the dbDefineSyncPin command?

somebody help me
 

Re: how to balance the skew of FFs that used to divide cloc

Hi sir,

Use "ataDefineSyncPin" command to define sync pin.

Best Regards,
chyau
 

Hi chyau

thank you for your help
I've tried the "ataDefineSyncPin" command,"ataDefineSyncPin (geGetEditCell) "u_digital1_top/u_clock/dutcks/ck_reg_0" '(("CPN" "nonInvertFall" (3.3 3.3) (3.3 3.3) (3.3 3.3)))

but the astro also give the error message "syntax ataDefineSyncPin CellID InstName Items"

so I am puzzled...

BTW:I used the soft configuration in clock common pannel to make these DFFs in the same level by force,and it worked

but how to use the "ataDefineSyncPin" command ?
 

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