Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

so lower dft coverage, why?

Status
Not open for further replies.
HolySaint

HolySaint

Full Member level 3
Full Member level 3
Joined
Aug 31, 2008
Messages
159
Helped
6
Reputation
14
Reaction score
3
Trophy points
1,298
Location
Mars
Activity points
2,109
tetramax fastscan coverage

Here i use estimate_test_coverage commond to estimate the testcoverage

what a low testcoverage

RPT
================================================

----------------------------------------------------------
#patterns #faults #ATPG faults test process
stored detect/active red/au/abort coverage CPU time
--------- ------------- ------------ -------- --------
Begin deterministic ATPG: #uncollapsed_faults=1755508, abort_limit=10...
Warning: Chain test pattern failed contention checking (ID=542). (M430)
0 77035 1673479 1013/2772/1173863 8.77% 513.36
Warning: 1152726 faults aborted during contention prevention. (M139)

Pattern Summary Report
-----------------------------------------------
#internal patterns 0
-----------------------------------------------

Uncollapsed Stuck Fault Summary Report
-----------------------------------------------
fault class code #faults
------------------------------ ---- ---------
Detected DT 77035
Possibly detected PT 155113
Undetectable UD 142983
ATPG untestable AU 11499
Not detected ND 1518366
-----------------------------------------------
total faults 1904996
test coverage 8.77%
-----------------------------------------------
Information: The test coverage above may be inferior
than the real test coverage with customized
protocol and test simulation library.
Click to expand...
==============================================

who can tell me which part may be wrong?
the design i load is produced by DC

Added after 3 minutes:

when i use preview_dft to list the reg,
i find almost all regs are ready to insert dft

do i understand right?
 

chain test pattern failed contention checking

You should check the dft_drc report. The report will tell u the dft violation information such as D1.D2.D3.... . Then fix them
 

    HolySaint

    HolySaint

    Points: 2
    Helpful Answer Positive Rating
test coverage dft

rsqf said:
You should check the dft_drc report. The report will tell u the dft violation information such as D1.D2.D3.... . Then fix them
Click to expand...

thx , i'll have a try.
if more violation is found,fix the timing in dc script can help,is that right?
 

dft+coverage

HolySaint said:
rsqf said:
You should check the dft_drc report. The report will tell u the dft violation information such as D1.D2.D3.... . Then fix them
Click to expand...

thx , i'll have a try.
if more violation is found,fix the timing in dc script can help,is that right?
Click to expand...


if the dft script is correct , and autofix does not work , u should change the RTL code to improve the dft coverage.
 

dft_drc in dft

mostly the controllability and observability cause problem.
you could try to report scan chain cell.
what I impressed is that some part of design is not correctly inserted into scan chain.
 

    HolySaint

    HolySaint

    Points: 2
    Helpful Answer Positive Rating
dft violation

Warning: 1152726 faults aborted during contention prevention. (M139)

there is no pattern is generated becasue of the contention violation. i dont know how the DC is calculating cvoerage.

can you try in tetramax or fastscan to check the coverage estimation.
in tetramax, issue " run drc " command, this will give you the all the deatils to violations..
 

    HolySaint

    HolySaint

    Points: 2
    Helpful Answer Positive Rating
dft atpg script

thx for everyone
i'll try tmax to detect it again
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top