I applied through university. The process took 2 weeks. I interviewed at Espressif (Pune) in Nov 2020
Interview
Espressif came to my college for campus hiring. Was a mixed experience. 2 technical rounds of interview post an aptitude and then final HR round. You need to have a clear understanding of the basics of DSA, operation systems and microcontrollers
I applied through university. I interviewed at Espressif
Interview
First round was Hackerearth MCQ and Coding test, with questions on OS, RTOS, CN. No aptitude questions.
Followed by the qualification test there were 3 rounds of technical interviews and a HR round.
I did not get shortlisted after the first interview.
Interview questions [1]
Question 1
First interview:
1) First repeating character in a string with O(N)
2) Check whether the given number is even with O(1) & without the modulo operator
3) Check whether the given number is power of 2 with O(1),
4) The 2 eggs and 10 floors problem.
5) Questions about I2S protocol, I2C vs SPI, design considerations for a PCB layout.
I applied through a recruiter. The process took 4 weeks. I interviewed at Espressif in Apr 2020
Interview
Interview process took around a month from HR getting in touch till they made an offer. There were three technical interviews conducted over a period of around two weeks. Interviewers were technically strong.
Interview questions [1]
Question 1
Round 1:
1. Few questions related to BLE Mesh fundamentals: Type of bearers, What is Friend Node, Foundation Model, BLE Mesh Layers.
2. Few questions related to BLE: Content of advertisement data and its Max Size, How to send more that Max_Size in advertising
3. C programming
a. Define link list node
b. Size of link list node with data type as int and char. [ focuse was on alignment, padding, and packed attribute ]
c. Write code to add note in link list
d. Function prototype of `memcpy` and write code for `memcpy`
e. How to avoid void pointer ++ operation
f. How assign more than one byte
g. Constrains using int pointer
h. When copying data what if source and dest addresses are overlapping
4. Data structure and Algorithms
a. Write code for whether number is power of 2
b. n + 1 elements in array(1 to n), one of the number if repeated, find it
c. n: elements, every number is repeated except one, find that
d. How to find the center of link list
5. OS fundamentals and System Design
a. Design system for smart light which is controlled by WAN, LAN and Physical button
Round 2:
1. How to sort an array of roll numbers, starts with 1, no holes no repetition. Expected time complexity O(n).
2. Puzzele: In a gaint wheel, man at position 6 O-clock is continuously firing, who all will be killed?
Round 3:
1. Two threads with infinite while loop, both have different volatile variable, one thread increments, another decrements. What happens in this case?
2. Implement Priority Queue