6.2.1. Basic Structure of Scan Chains

Try these first

1. 1.

   What is the purpose of Scan-In in a scan chain?

   Hint

   Think about where data enters during testing.

2. 2.

   Name one of the components of a scan chain.

   Hint

   Consider the building blocks we discussed.

3. 3.

   What is the purpose of Scan-In?

   • To output test results
   • To enable normal operation
   • To input test vectors

   Hint

   Think about what data you put into the system.

4. 4.

   True or False: The Scan Enable signal is used to switch between normal and test modes.

   • True
   • False

   Hint

   Consider how you toggle operations.

5. 5.

   Design a simple scan chain consisting of four flip-flops. Explain how you would connect the Scan-In and Scan-Out, and describe the role of the Scan Enable signal.

   Hint

   Think about the flow of data through the flip-flops.

6. 6.

   Explain the potential drawbacks of having a very long scan chain in terms of power consumption and testing efficiency.

   Hint

   Consider both operational and design perspectives.