10+ Fpga Design Engineer Interview Questions and Answers

FPGA stands for Field-Programmable Gate Array, a type of integrated circuit that can be reconfigured after manufacturing.

• FPGA is a type of hardware that can be programmed to perform specific tasks.

• It consists of a matrix of configurable logic blocks connected via programmable interconnects.

• FPGAs are commonly used in applications such as signal processing, data processing, and control systems.

• Examples of FPGA manufacturers include Xilinx, Intel (formerly Altera), and Lattice S...read more

Blocking and non-blocking are two types of assignments in Verilog that differ in their execution order and timing.

• Blocking assignments execute in a sequential order and the next statement waits for the current statement to complete before executing.

• Non-blocking assignments execute concurrently and the next statement does not wait for the current statement to complete before executing.

• Blocking assignments are used for combinational logic while non-blocking assignments are used...read more

Code for read and write file

• Use fopen() function to open a file

• Use fprintf() function to write to a file

• Use fscanf() function to read from a file

• Close the file using fclose() function

CDC stands for Clock Domain Crossing. It refers to transferring data between different clock domains in an FPGA design.

• CDC occurs when signals cross between different clock domains in an FPGA design

• CDC can lead to metastability issues if not handled properly

• Common CDC techniques include synchronizers, handshake protocols, and FIFO buffers

• Examples of CDC techniques include 2-flop synchronizers, Gray coding, and CDC FIFOs

To make an AND gate using NAND gates, connect two NAND gates in series.

• Connect the outputs of two NAND gates together

• Connect the inputs of the two NAND gates to the same inputs

• The final output will be the AND of the two inputs

RAM and FIFO are essential components in FPGA design. Here's how to write code for them.

• For RAM, define the memory size and data width, then instantiate the memory module and write/read data using the address bus and data bus.

• For FIFO, define the depth and data width, then instantiate the FIFO module and write/read data using the write and read pointers.

• Use synchronous or asynchronous reset signals to initialize the RAM and FIFO modules.

• Consider the clock frequency and timing...read more

Task and function are both subprograms in Verilog/SystemVerilog, but task is used for procedural blocks and function is used for expressions.

• Task is used for procedural blocks and can contain delays and event control statements.

• Function is used for expressions and cannot contain delays or event control statements.

• Functions can return a value, while tasks cannot.

• Functions can be called from within tasks or other functions, while tasks can only be called from within procedural ...read more

Use a frequency counter or oscilloscope to measure the period of a known signal and calculate the frequency.

• Measure the period of a known signal using a frequency counter or oscilloscope.

• Calculate the frequency using the formula: Frequency = 1 / Period.

• For example, if the period of the signal is 10 ms, the frequency would be 1 / 0.01 = 100 Hz.

A HalfAdder program in VHDL is used to perform addition of two binary digits without considering the carry.

• Declare two input signals A and B of type std_logic.

• Declare two output signals Sum and Cout of type std_logic.

• Implement the XOR gate for Sum and AND gate for Cout.

• Example: A <= '1'; B <= '0'; Sum <= A XOR B; Cout <= A AND B;

Reset is a signal used to initialize the system or a specific module.

• Reset is used to bring the system or module to a known state.

• It is an asynchronous signal that overrides all other signals.

• There are different types of resets such as power-on reset, soft reset, hard reset, etc.

• Reset can be active high or active low depending on the design.

• Reset can be generated internally or externally.

• Reset can be used to clear registers, counters, and other state elements.

Improving logic used in FPGA design involves optimizing resource utilization, reducing power consumption, and enhancing performance.

• Utilize efficient coding techniques to minimize logic complexity

• Implement pipelining to improve performance

• Use advanced synthesis and optimization tools to reduce resource usage

• Optimize clocking strategies to minimize power consumption

• Consider parallel processing to increase throughput

Design a counter using flip-flops to count up or down based on the input signal.

• Use D flip-flops to store the count value

• Connect the output of one flip-flop to the input of the next flip-flop to create a ripple effect

• Use additional logic gates to control the direction of counting (up or down)

• Implement a reset signal to initialize the counter to a specific value