Microsoft

Code Review or Design Interview: For technical roles, there may be a code review or system design interview during the on-site process. You might be asked to solve problems on a whiteboard or demonstrate your approach to designing systems.

HR is very nice and gives very helpful support. The interview process includes 5 rounds, and every round requires solving an algorithm problem and writing code on a whiteboard. You also need to write some tests to go through your code.

Ask about basic embedded interfaces like SPI and I2C. Discuss algorithms to sort data. Then, ask very detailed questions about the projects I have done before, using C++11 standard library.