# 149

Senior Verification Engineer interview questions shared by candidates

## Top Interview Questions

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Senior Hardware Verification Engineer was asked...January 30, 2010

### Describe a function to check if an integer is a power of 2.

Write the number in binary and count the number of ones in that.If the number os ones is only 1 then it the number is indeed a power of 2 Less

For an integer n: If n is less than 1, return false. If the bitwise &amp; of n and n-1 is 0, return true. Otherwise, return false. Less

I think the main idea is to use recursion function, for the integer which is larger than 0, if it is 1 return true, else return function(n-1) Less

### Calculate fifo depth for following data rate Writing Data = 80 DATA/100 Clock (Randomization of 20 Data’s) Outgoing Data= 8 DATA/10 Clock. Burst size = 160

In this case : 20 Data + 80 Valid Data + 80 Valid Data + 20 Data For best case , we have 160 Data writes in 160 clock cycles . For worst read case : In 10 clocks 8 data will be read In 160 clocks (8*160)/10 i.e. 128 data reads So depth of fifo = 160 -128 =32 Less

In this case , we can have several combinations like : 20 Data + 80 Valid Data + 80 Valid Data + 20 Data For best case of write 160 data will be written in 160 cycles . For worst case of read : 8 data will be read in 10 clock cycles And in 160 clock cycle ,it will read (8*160/10) i.e. 128 Fifo depth is 160-128 =32 Less

Answer 32 Best case write = 160 data in 160 cycles Worst case read = ( 160 * 8/10) = 128 data in 160 cycles Depth = 160 - 128 = 32 Less

### Describe a circuit that implements the following truth table using only NAND gates. A B OUT 0 0 1 0 1 1 1 0 0 1 1 1

out = (A NAND (B NAND B))

OUT = (A NAND (B NAND 1)) or out = (A NAND (B NAND B)) like what anonymous said. Less

out = ((A NAND A) NAND (A NAND A)) NAND (B NAND B)

### Implement a 10:1 mux using 3 4:1 muxes

google it ( EE course assignment)

4 inputs to mux#1, another 4 inputs to mux#2, 2 other inputs plus o/ps of mux#1 and mux#2 are inputs to mux#3 Less

There's a lot of elements to typically cover in these questions, clarifications, scoping, making sure you're answering the actual question the interviewer is looking for you to answer, etc. Could be worth doing a mock interview with one of the Prepfully Nvidia Senior Verification Engineer experts... they've worked in the role so they clearly know how to get through the interview. prepfully.com/practice-interviews Less

### (Unexpected) What the types of caches?

two types: fully associative cache and N-way associative cache

1. Fully Associative. 2. Direct Mapped. 3. Set Associative

L1, L2 and L3 caches

### There are 5 bowls with 100 candies each. In 4 bowls, all of the candies are 10 grams each. In 1 bowl, all the candies are 9 grams each. Using a digital scale, how can you determine which bowl has the 9 gram candies by using only 1 weighing?

Take 1 candy from bowl 1, 2 candies from bowl 2, 3 candies from bowl 3, and 4 candies from bowl; and weight them on the digital scale. If the total weight is 100 grams, the 9 gram candies are in bowl 5. If the total weight is 99 grams, the 9 gram candies are in bowl 1. If the total weight is 98 grams, the 9 gram candies are in bowl 2. If the total weight is 97 grams, the 9 gram candies are in bowl 3. If the total weight is 96 grams, the 9 gram candies are in bowl 4. Less

if weighing machine can weigh the bowls: Put 2 bowls on each side, if they weigh equal then last bowl has candies with 9 grams. If the bowl weigh different then weigh the 2 bowls with lower weight and find the lowest weight bowl. Less

### They started with project related questions.

I told whatever I did in my project and how I come across the difficult situations I faced. Less

### Difference between blocking and non- blocking

Differneces are given in most of the sites