Problem about DFT Complier

[iamlaogong]

dft set_scan_configuration

It's my first time to use DFT Complier for scan insertion. But it always adds all FFs in the scan chain, that means full scan. It costs a lot of area.
How can I specify some critical FFs to be added in scan chain, while others remain out of the chain?
I'll be very appreciate your help.

My script is as follow:

current_design $TOPLEVEL
compile -scan
set_test_hold 1 TM
create_test_clock TCLK -period 100 -w {45 55}
check_test
set_scan_configuration -style multiplexed_flip_flop
set_scan_configuration -chain_count 1
set_scan_configuration -bidi_mode input
set_scan_configuration -clock_mixing mix_clocks
set_scan_signal test_scan_in -port [list SI]
set_scan_signal test_scan_enable -port [list SE]
set_scan_signal test_scan_out -port [list SO]

preview_scan -show all
insert_scan
check_test
report_test -scan_path

 

[anjali]

put dont_touch attribute on the cells, which u dont want to be scanned.

 

[iamlaogong]

hello， anjali
i use set_dont_touch on those cell i don't want to be scanned.
but i seems that no scan chain will be inserted if adding set_dont_touch.

can you show me an example script?

thank you very much

 

[adrescuer]

Hi
DFT Compiler and TetraMAX support only FULL SCAN TEST.

I think it's better to separate the desired sections of the chip as independent
modules and insert scan for that modules, separately.

bye

 

[iamlaogong]

hi,adrescuer
we can add this in script: set_scan_configuration -methodology full_scan/none
what dose this "none" mean?
No scan?

regards