Graduate Engineer Trainee

1. Storage classes in C.
2. What is extern in C? Scope of variables and functions, etc.
3. More questions on C like structure, union, structure padding, etc.

1. Complete process of how an instruction in assembly is executed. What are the different registers involved. 
2. USB protocol related basic questions like what are the different classes, what their applications, etc. Please note that I was asked this question only because I worked on USB Class in previous company and I had mentioned it in resume. 
3. Serial protocols in Embedded System like UART, I2C, SPI, etc. Which protocol is used in which case, what is the advantage of x protocol over y protocol, etc. Basically they check how well you understand the protocols from application point of view. 
4. What was the most difficult task/challenge in your previous job and how did you handle it?

Questions related to work done at previous company and the product.