Qualcomm Firmware Engineer Interview Questions | Glassdoor

Qualcomm Firmware Engineer Interview Questions

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Helpful (7)  

Firmware Engineer Interview

Anonymous Employee in San Diego, CA
Accepted Offer
Negative Experience
Average Interview


I applied online. The process took 4+ weeks. I interviewed at Qualcomm (San Diego, CA) in November 2011.


phone interview. and after that, on site interview. I spoke with 5 people. they never really asked anything crazy since i was fresh out of school. they do not require any knowledge about algorithm or data structures. As long as you know for loop/while loop, that's all you need.

Interview Questions

  • you have 50 white balls and red balls. you want to distribute them such that it maximizes your chance of picking a red ball when you select one randomly.   Answer Question

Other Interview Reviews for Qualcomm


    Firmware Engineer Interview

    Anonymous Employee in San Diego, CA
    Accepted Offer
    Neutral Experience
    Average Interview


    I applied through a staffing agency. The process took a week. I interviewed at Qualcomm (San Diego, CA) in October 2011.


    Phone Interview -
    Was asked computer architecture questions about bit handling and manipulation,
    About previous experience,
    And about school projects.

    Interviewer walked me through one of the puzzle questions, which I thought was unusual, but kind.
    Interviewer also described the position in exact detail, to avoid confusion.
    Felt fairly confident after the interview, as I answered every question.

    Interview Questions

    • Name a few different types of registers.   2 Answers
    • How many pins in a JTAG cable?   5 Answers

  2. Helpful (28)  

    Firmware Engineer Interview

    Anonymous Employee in San Diego, CA
    Accepted Offer
    Positive Experience
    Difficult Interview


    I applied online. The process took 4 weeks. I interviewed at Qualcomm (San Diego, CA) in February 2011.


    Overall Qualcomm is very organized. And Very professional

    Interview Process:
    Applied Online
    After about two weeks HR e-mail me to set-up phone interview. Then I had a phone interview on same day.

    During Phone interview key question I asked is "do you have any concerns about me?" He told me he wants some body committed to position at least two years. Also He told me he will set me up for onsite interview.

    After another week HR e-mail me for on site interview.
    On site is with 1 HR and 5 Engineers on same department

    HR Will ask you how much money you made in previous job. Why you want to quit the job (I was currently employed), why you want to work @ Qualcomm, your future goals...

    Then the fun starts with the five engineers.

    Each interview takes about an hour. Lunch is also an interview.

    Each interviewer is very professional; however they will test you until you break to see how you handle. Based on my experience they're not testing to see if you know everything, it's more of testing your personality, and how your problem solving skills.

    My advice is making sure you know every word you on your resume. If you don't know the answer or don’t understand the questions, ask them questions. They were in our seat long time ago. They know what we going thru. Don’t give vague response that doesn’t really answer the question. They’re looking for short answers with the correct keywords. Not an essay answers.
    Before ending the interview make sure they can tell what are your strong points and weak points.
    Don't feel bad if you lose confidence after interview. That's normal for Qualcomm interviews. It’s like the last day of finals. You will be burned out by end of day.

    Good thing is 90% of questions will be based on what you put on your resume, while 10% will be problem solving skills.

    After onsite interview in two weeks HR called me saying “Congratulation and they will contact people I put as reference” That mean pretty much you got the job. Unless your reference don’t give good recommendation
    Then about week later HR will wants a copy of your degree. That’s it. After that you get an offer?.
    They don’t really have much room to negotiate. Initial offer is very competitive and attractive.

    One of the things I did is I wrote thank you letter after phone interview and onsite interview. I only knew HR e-mail. So I wrote to the e-mail to HR but I addressed everyone. You should do that too. I am not sure if it helps, but it certainly doesn’t hurt.

    Interview Questions

    • Programming Related:

      * what is the keyword volatile, static, const do?
      * where do static data reside in memory?
      * What are some ways to pass data into a function? and what the advantage and disadvantages?

      O/S Related
      * What makes an OS real time?
      * Difference between Semaphore, Mutex, and spin locks?
      * What is priority inversion, and what are methods to avoid it?
      * If processor has a FP unit, is it ok to use FP inside kerenel? why/why not?
      * What is is the difference between Non-blocking vs blocking calls? What are the benefits of each?
      * How would you execute a non-blocking call in kernel?

      Debuggin Related:

      * What is stack trace?
      * What data get pushed into a stack when jumping into a function call?
      * Give some example you would use a scope to trouble shoot software problem? What line would you use to trigger the scope?

      I/O Interface Related:

      * Explain UART communication protocol?
      * What signals are connected to DB9 connector, and how are they beeing used?
      * What are some ways UART could have communication error?
      * Explain I2C Communication protocol. How the Start, Stop condition generated? How do you select which device to communicate when all the devices tight to gether?
      * Explain SPI Communications.   Answer Question
    • Programms to Write:

      * Find what's wrong with this function?

      void copydata(uint8_t *datato, uint8_t *datafrom, int size)
      uint8_t *CurrentAddress = datafrom;
      uint8_t *StopAddress = datafrom + size;

      for(;CurrentAddress <= StopAddress;CurrentAddress++)
      *CurrentAddress = *datafrom++;


      * Write algorithm to find missing element in array. For example

      int array[5] = {1, 2, 0, 3, 4};

      this array should contain # from 1 to 5. # 5 is missing.

      * find a element in array size of n using binary search method.

      * Write a small program that add element into linked list at beginning of the list, and back of the list?

      * Swap the bit order in a byte (example bit 7 would goto bit 0, bit 0 would goto bit 1)

      * Write a small test program that would test the read/write memory? What good value to write if you want to test if there two data lines tight together?   Answer Question
    • Puzzles 1:

      You have rope that take 60 min to burn. Speed of burning is not uniform. Example: it doesn't take 30 min to burn half

      Using two ropes, how would you get 45 min?


      First Rope. Burn both ends at same time
      Second Rope: Burn only one side.

      when First rope is totally burn, it's been 30 min, now burn the rest of second rope both ends. Which should take additional 15 min.

      30 + 15 = 45 min.

      Puzzle 2:

      There is a guy in a boat holding a rope that's tight to a Top of pole in the shore. He keep pulling the rope until he reach the shore. What is the speed relationship between amount of rope he pulls, vs horizonal speed? Which speed is higher?


      Horizonal speed is faster than the amount of rope he pulls. (Horizonal distance he travel is higher than amount of rope he pulls, by triangle theory where sum of two sides must be greater than 3rd side)

      Puzzle 3:

      in Analog Clock, It's exacly 3:00 Clock. What time would the Hour hand, and Min hand would overlap each other?   4 Answers
    • This is from my friend who had a kernel development position interview. This is only phone interview.
      This is just from a phone interview:
      How did you port uCOSII to the product?

      How did you verify the worst case time delay?

      What are the key features that you are looking for the RTOS?
      (I mentioned the size, semaphore, event flags, and priority inheritance)

      What are cache write back and write through? give examples in what situation you use which?

      What are the major difference for the MCU and processors you are using?

      What are the top considerations you pick those processors or MCU?

      What are the programming model difference among those processors?

      What is volatile? examples of using it.

      A programming question:
      int32 multiplication( int16 a, int16 b)
      a "*" operator inside the func only takes 8 bit operands. what's the implementation?
      (I was a little bit stuck on the sign bit)

      What's the difference between DSP and MCU?
      (I guess he was looking for the Harvard architecture, I didn't get that until he mentioned that)

      What is the difference between desktop programming and embedded programming?   Answer Question
    • This is for DSP Position phone interview
      Today I got phone interviewed for the DSP team. The scheduled time was 30 min, it went to about 50min, mostly because I talked too much, which is not very good thing.

      The first half an hour, he asked me a lot of questions on my resume

      1. How did you port rtos?
      2. what was the precise timing control?
      3. How did you improve FFT?

      In the second part he was focused on comm and dsp concepts,

      how to implement a FIR
      how to implement a filter with FFT?
      if PLL has statibily issue, where to look?
      Cell phone power control down to the radio power and already in the min power, how to reduce the interference to others?
      In signal space, the modulated signal got closer and closer, how to get better demodulation?   Answer Question


    I did not negotiate.


    Firmware Engineer Interview

    Anonymous Interview Candidate in San Diego, CA
    No Offer
    Neutral Experience
    Difficult Interview


    The process took 1 day. I interviewed at Qualcomm (San Diego, CA) in April 2008.


    The hiring manager gone through a 45 minute technical interview. They try to understand your background, work experience, and finally technical question in your area. After a successful phone interview, they flew me for onsite interview, where you meet with different engineer. the schedule was tight, and they only have time to ask 30-45minutes. The interview was very technical, going over aspect of firmware development, debugging, implementing c code, and some problem solving question. The problem solving questions are easy if you are just out of school, but it would be difficult for old-timer because you have to remember geometry/Trigometry.

    Interview Questions

    • given the code in C, it involve double pointers, and you have to dereference the double pointer. How is the double pointer going to look like in main memory.   1 Answer

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