Mostly based on things listed on resume. Basic C questions on key words like static, const, volatile. Pointers, semaphores, mutexes. Different memory regions: .bss, .data, .txt. What does ISR return? What happens when interrupt occurs. What is a reset vector. Asked to write me a static circular queue. Asked to write a decoder driver given a DMA address. Asked to write a binary search tree given a pointer to a pointer.