I was contacted by a manager for a phone screen. He told me it would just be a 30-minute phone screen, so I expected it to be just on my resume and prior experiences.

The first 15 minutes were just that, but then the last 15 minutes switched to open-ended yet very specific technical questions, such as when would you need two watchdog timers in a system.

I was caught off-guard by the sudden shift to deep technical questions, and I was unable to answer most of them adequately. I was sent an automated rejection email a few days later.

What is a watchdog timer?

Why would you use more than one of these in a single system?