what is the difference between sequential ATPG and combinational ATPG

[raviram80]

Hi ,

I have the following questions

1. What is combinational ATPG and sequential ATPG?

2. When we generate patterns for normal stuck-at faults what are we using? Combinational ATPG or Sequential ATPG?

Thanks

 

[jpvSoccer]

Hi,

sequential ATPG implies memory state elements

combinatorial ATPG implies combinational logic only.

A stuck at fault can happen anywhere; on pads, on flops or combinatorial gates

 

[raviram80]

Hi,

sequential ATPG implies memory state elements

combinatorial ATPG implies combinational logic only.

A stuck at fault can happen anywhere; on pads, on flops or combinatorial gates

I dont think this is what it means in terms of combinational or sequential ATPG

 

[jpvSoccer]

Hmmmm...educate me please

 

[ConradATPG]

ATPGs generally work on designs that have the flip-flops connected into a scan chain. This allows you to load values into them before tests and see values that they capture after a test is applied. It converts a sequential test problem into a much simpler combinatorial problem because the tests can generally be written with one clock. The values flow from the scan flops through logic to flip-flops which capture the test results where they can be compared against the expected value to find defects.

 

[antique.2011]

The basic difference between combinational and sequential ATPG is that, during sequential ATPG, one test vector may be insufficient to detect the target fault because the excitation and propagation conditions may necessitate some of the flip flop values to be specified at certain values.

 

[tyuga454]

Combinational ATPG will generate the Patterns for Combo logic(gates...etc)and sequential ATPG will generate the patterns for Scan-Filpflops.

Correct me if my understanding is wrong

While generating the patterns we need to generate the patterns for combinational and sequential circuits.right??
So,Now,
1)How do we generate the patterns??
2)which ATPG(combinational ATPG or sequential ATPG) we use to generate the patterns which is having combinational and sequential circuits in the design??

Thanks in advance.

Rgds,
yuga