Interview Questions on Microcontrollers

Hi, in this post I add up few questions which are generally faced by an experienced/fresher who is looking for a position as Embedded Software Developer(firmware engg) in companies such as Qualcomm, Broadcom, securify, moschip, Global Edge, Aricents, Mirafa, Graphene, Mojo Networks, Lantronix, Adtran, Votary Softech, Xilinx, Microchip. For further queries add a comment, be precise in the question you post. You can look related topics to find answers to my questions.

  1. Differences between following
    1.  Microcontroller and Microprocessor
    2.  RAM and ROM
    3.  Address bus and Data bus
    4.  Virtual address and Physical address
    5.  Memory Mapped IO and Port mapped IO
  2. Knowing following terms is must
    1. FPU – Floating Point Unit
    2. ALU – Arithmetic Logic Unit
    3. DMA – Direct Memory Access
    4. ADC – Analog to Digital converter
    5. DAC – Digital to Analog Converter
    6. Mux Unit
    7. Timer Unit
    8. Clock generator
    9. PMU- Power Management Unit
    10. AHB – AMBA High-performance Bus
    11. APB – Advanced Peripheral Bus
    12. Watch Dog
    13. MMU – Memory Management Unit
    14. DSP – Digital Signal Processor
    15. GPIO
    16. JTAG
    17. PC – Program Counter
    18. LR – Link Register
    19. SP – Stack Pointer
    20. ICU – Interrupt Control Unit

Questions

  1. What address is used to access code and text ?
  2. Will peripherals such as DMA use virtual address or physical address ?
  3. What all operations can and cannot be done by JTAG ?

 

Embedded MCU Specific Coding and Execution Questions

  1. What are Memory Leaks, what are the effects of it ?
  2. How to detect Memory Leaks ?
  3. What is interrupt ? What is it used for ?
  4. What happens when an Interrupt occurs ?
  5. What is that should and should not be done in ISR ?
  6. How long can an ISR be ?
  7. What happens if a ISR is lengthier ?
  8. How is ISR invoked, what happens before invoking ISR, how will a ISR be chosen ?
  9. What is Interrupt nesting ? Benefits and effects ?
  10. What is IVT and what it contains ? What is its location ? Will it be in RAM or FLASH ideally ?
  11. Why does stack grow downwards ? any benefits ?
  12. What is stack overflow ? How can you detect Stack Overflow ?
  13. Can a recursive function which has no local variables nor input parameters create stack overflow ? Answer
  14. What are the rules to be followed in writing recursive functions ?
  15.  What is the purpose of using Stack and Heap ?
  16. What is race condition ? how to avoid it?
  17. How will virtual address be converted to physical address ?
  18. What is ISR and DSR ?
  19. Alignment and benefits and purpose ?
  20. Diff between data and bss section?

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