5.2. Concept of Scan Chains

Try these first

1. 1.

   What is a scan chain?

   Hint

   Think about how data is passed in tests.

2. 2.

   Define scan-in.

   Hint

   It’s the input phase of testing in a scan chain.

3. 3.

   What is the primary purpose of a scan chain?

   • Enhance processing speed
   • Improve testability
   • Minimize power consumption

   Hint

   Think about why designers implement additional testing features.

4. 4.

   True or False: Scan-out is the process of inputting test data into the scan chain.

   • True
   • False

   Hint

   Recall the definitions of scan-in and scan-out.

5. 5.

   Given a digital circuit with a scan chain of 7 flip-flops, how would you apply a test vector to detect a stuck-at fault?

   Hint

   Think of how you'd set up the inputs for each flip-flop.

6. 6.

   Discuss the engineering trade-offs when integrating scan chains into an existing design. What factors must be considered?

   Hint

   Reflect on how adding components changes circuit dynamics.