Aeron Embedded Developer interview questions

1st round 1.As usual questions were asked based on the CDAC project how the device driver works internally ?Explain it with a block diagram in brief as well as some sort of code which we had implemented like Ioctl operations & how commands are passed to the kernel,device Intialization ,etc. 2.In a constraint embedded device how could you implement your own driver apart from OS environment. 3.All protocols like SPI , I2C ,UART,CAN Difference between uart& usart How can we interface an spi with a multiple devices explain it with example 4.Some sort of questions based on c coding like types of array with their implementation in real life ,pointers ,create a functions which include pointers, etc