Help me understand some DFT violations

[gold_2007]

Hi

=>i am given a netlist where the designer has specified PLL present but external mux used to bypass PLL clocks using scan mode setup . what does this signify.
can u elaborate .
=> i ve come across a non scan model TLATNTSCAX2MTH , how do i make it transparent . It has CLK and D input both set to X.

=> i am getting 7809 S1 violation and most of these S1 violation instances come across non scan model TLATNTSCAX2MTH . so what need to be done .

PLEASE REPLY

 

[alok_msh]

Re: dft violations

If the input clock to TLATNTSCAX2MTH is X then the problem is somewhere downstream. If TLATNTSCAX2MTH drives the clock you need to make sure that in shift/capture mode it is able to drive clock. You might need some changes in netlist.

 

[Nithyanantham]

Re: dft violations

==>As you have mentioned in your design external mux is provided. External mux is used to bypass the PLL clock & test clock will be provided to the design. For transition you have to use PLL clock for capture. For stuck-at you can use test clock.

==>Ensure the model is flop or latch. S1 indicates that whether DFTA is able to change the sequential cell to scannable one

==>Since u have got around 7000 violataions try to put a mux in the downstream(Upper level hierarchy) to resolve s1. Don't let the tool to put the muxes.

 

[gold_2007]

Re: dft violations

==>As you have mentioned in your design external mux is provided. External mux is used to bypass the PLL clock & test clock will be provided to the design. For transition you have to use PLL clock for capture. For stuck-at you can use test clock.

==>Ensure the model is flop or latch. S1 indicates that whether DFTA is able to change the sequential cell to scannable one

==>Since u have got around 7000 violataions try to put a mux in the downstream(Upper level hierarchy) to resolve s1. Don't let the tool to put the muxes.

"Since u have got around 7000 violataions try to put a mux in the downstream(Upper level hierarchy) to resolve s1". Don't let the tool to put the muxes. u mean to say in post scan netlist or prescan netlist .