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Last Updated: Jun 20, 2024 Easy

Embedded Systems Interview

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Tanay kumar Deo
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Introduction
An embedded system combines hardware
and software for specific tasks on a
computer. It is widely used across industries
and is poised for significant growth, driven
by investments in artificial intelligence and
computing.
So, here we have prepared a bunch of top
embedded interview questions in this article
that covers the the most asked embedded
systems interview questions. So let's get
started with the embedded interview
questions and answers.

30 Commonly
Asked
Embedded
Interview
Questions With
Answers
In this section, we will cover the most
commonly asked Embedded Interview
Questions and answers we can study to be
better equipped to face our interview.

1. What is embedded system?

Explanation: An embedded system
combines computer software and hardware
designed to perform a specific function.
Embedded systems can also function within
a more extensive system or machine. They
can be programmable or have a fixed
functionality. Some examples of an
embedded system are Industrial machines,
consumer electronics, agricultural and
processing industry devices, automobiles,
mobile devices, etc.
2. Mention the essential
components of the embedded
system?
Explanation: An embedded system has the
following essential components for working
of its hardware:

Power Supply: The power supply is the

essential part of an embedded system
circuit.
Processor: A processor is the main
brain inside an embedded systems=.
Memory: Memory is used to store data
and instructions in an embedded
system.
Timers: These are the counters.
Communication Ports.
Input and Output.
Application-Specific Circuits.

Embedded system software: Softwares in

an embedded system are a set of codes
written to carry out various/specific
functions. Most embedded system software
runs on micro-controllers. It checks on the
availability of System Memory and
Processor Speed.

Real-Time Operating System (OS): It runs a

process as scheduled and performs
switching from one process to another as
and when required.

3. What is a real-time embedded

system?
Explanation: Computer systems that
monitor, respond to, or control an external
environment are called real-time embedded
systems. Actuators, sensors, and input-
output interfaces connect this environment
to the computer system.

4. What are microcontrollers?

Explanation: In an embedded system, a
microcontroller is a small integrated circuit
that governs a specific operation. On a
single chip, a microcontroller contains a
CPU, memory, and input/output (I/O)
peripherals. A microcontroller is a self-
sufficient system that may be used as an
embedded system.

You can also read 8051 Microcontroller Pin

Diagram here.

5. What are the differences

between a microcontroller and a
microprocessor?
Explanation: Here are the differences
between Microprocessor and
Microcontroller.

Microprocessor Microcontroller

Microprocessors Microcontrollers
are the heart of any are the heart of
Computer system. any embedded
system.

It is just a Microcontrollers
processor, so I/O have a processor
and memory along with I/O and
components are internal memory
connected components.
externally.

I/O and memory I/O and memory

are connected are present, and
externally, so the the internal circuit
internal circuit is small.
becomes complex.

We can’t use it in We can use it in

compact systems compact systems.

The cost for the The cost for the

entire system is entire system is
high low

Total power Total power

consumption is consumption is
 high. less.

6. What is the DMA address? And

what does it deal with?
Explanation: Direct memory access (DMA)
is speeding up memory operations by
allowing an input/output (I/O) device to send
or receive data directly to or from the main
memory, bypassing the CPU.

DMA addresses deal with physical

addresses. During data transfer, it is a
device that directly drives the data and
address bus. As a result, it's only a physical
address.

7. What is interrupt latency? How

to reduce it?
Explanation: The period between when an
interrupt/process is triggered and when the
interrupt handler begins to execute is known
as interrupt latency. This is hardware-
dependent and cannot be improved in
software for a single isolated interrupt.

However, If a lower priority interrupt is

triggered while a higher priority interrupts
handler is active, the lower priority one will
start later, increasing the interrupt latency.
In this scenario, reducing interrupt handler
execution time reduces the interrupt latency
for equal or lower priority interruptions.

8. What are the buses used for

communication in an embedded
system?
Explanation: The buses used for
communication in embedded systems
include

I2C (Inter-Integrated Circuit) is used to

communicate between numerous
integrated circuits (ICs).
CAN (Controller Area Network) is a
network protocol that's utilized in cars
 with a centrally controlled network.
USB (Universal Serial Bus) is a
standard for communicating between a
computer's processor and peripheral
devices such as a mouse.

9. Explain the need for an infinite

loop in an embedded system?
Explanation: For repeated processing or
monitoring of the program's state,
embedded systems require endless loops.
Consider the example of a program that is
constantly checked for any unusual
mistakes that may occur during runtime,
such as memory outage or dividing by zero,
etc.

10. What is a semaphore?

Explanation: In a concurrent system, such
as a multiprogramming operating system, a
semaphore is an abstract data type or
variable used to regulate access to a shared
resource by many processes. Semaphores
are used for two main purposes.

To be able to share a common

recollection
To grant others access to files

11. What are some applications

of an embedded system?
Explanation: The following are the
applications of embedded systems:

Using a speed-checker device, detect

reckless driving on highways and alert
traffic officials.
Control street lights and detect vehicle
movement on highways.
A density-based traffic signal system
regulates signal timing at intersections
based on traffic density.
Using a GPS modem, determine the
exact location of a car.
For a home automation system with a
remote control based on an Android
application.
12. What is a real-time embedded
system?
Explanation: A real-time embedded system
is a computer system that monitors,
responds to, or controls external
environments.

13. What are the uses of a timer?

Explanation: The various uses of timers in

embedded systems are as follows:

It is the RTC (Real-Time Clock) for the

system
It initiates an event after a provided
time delay.
It captures the count value of an event.
It finds the time interval between any
two events.
It reduces the time spent on various
processes/tasks.
It schedules tasks in RTOS

14. What is a Watchdog timer?

Explanation: A watchdog timer is an
electronic device dedicated to a specific
operation after a specified time if anything
goes wrong with the system.

15. What are some common

errors in an Embedded system?
Explanation: Some of the common errors
encountered in an embedded system are as
follows:

Data lines malfunctioning.

Some memory locations become
inaccessible.
Address line malfunctioning due to a
short in the circuit.
Damage to memory devices.
Wrong control signals.

16. State the differences between

a mutex and a semaphore?
Explanation: The differences between a
mutex and a semaphore are listed below in
the table:

MUTEXES SEMAPHORES

It is only released It can be signalled by

by the acquired another thread or
thread. process.

Mutexes have a The thread owner is

known owner. not known.

It provides a It is a
deadlock-free synchronization tool
mutual that can overcome
exclusion. that critical section
problem.

They are binary Semaphores are

semaphores. counter locks.
Their states are
locked or
unlocked.

17. What is a recursive function?

Explanation: The technique of repeating
objects in a self-similar manner is known as
recursion. A recursive call of the function
occurs when a program permits you to call a
function inside another function.

18. What are memory leaks?

Explanation: A memory leak is a resource
leak that occurs when a computer software
poorly controls memory allocations,
preventing memory from being freed that is
no longer needed. When an item is saved in
memory but cannot be accessible by the
running code, this is known as a memory
leak.

19. What is the automotive

embedded system?
Explanation: An automotive embedded
system is a computer system that can act as
a control system for electronic devices that
affects the mechanism of the automobile or
its data.

20. What is an embedded C?

Explanation: Embedded C is an extended
version of the C programming language. We
can use it to develop applications based on
micro-controllers like device drivers (WIFI
device drivers, Camera device drivers, etc.)

21. What causes segmentation

fault error in embedded C?
Explanation: A segmentation fault error in
embedded C is a runtime issue that can
occur for a variety of reasons.

It's possible that a pointer doesn't have

a proper address or memory location to
point to.
If the user tries to access a memory
location that is read-only.
If the user tries to release a memory
that has already been freed (through a
pointer).

22. Why do we use a ‘volatile’

keyword in embedded C?
Explanation: The volatile keyword prevents
the compiler from doing any optimizations
on objects that can change in ways that the
compiler cannot predict. Objects marked as
volatile are not optimized because their
values can be modified at any time by code
outside the scope of the present function.

23. What are Soft and Hard real-

time systems?
Explanation: A hard-real-time system is one
in which missing even a single deadline can
result in total or catastrophic system failure.
A soft real-time system is one in which one
or more failures to reach the deadline are
not seen as complete system failures, but
rather as decreased performance.

24. What are the various levels of

testing in an embedded system?
Explanation: We have four levels of testing
in an embedded system:

Unit testing.
Integration testing.
System testing.
User acceptance testing.

25. What are the phases of the

Software Development Life Cycle?
Explanation: The software development life
cycle is divided into five stages:

Customer Requirement: During this

phase, the customer fills out a
requirement form in which they write
down exactly what they require from
the product.
Analysis: The requirements are
transformed into documents in this
phase, which include all of the
functional requirement specifications.
Design: During this phase, the product's
design is finalised. The requirements
are translated into a design for
architecture. The following items are
included in this phase:
a.) Design Documentation at the
Lowest Level (LLD)
b.) Design Documentation at a High
Level (HLD)
Coding: The requirements are
transformed into a coded form during
this phase.
Testing: During this phase, the software
under development is put to the test to
ensure that it is of high quality. There
are two forms of this:
a.) Testing in a static environment
b.) Testing in a dynamic environment
Maintenance: During this phase, the
 product's maintenance is carried out.

26. What is software quality

assurance?
Explanation: Software testing and quality
assurance refer to the software
development process:

Improving and monitoring the process

Ensuring that procedures and
standards are followed
Ensuring that the problems are found
and corrected or rectified.

27. What is equivalence

partitioning?
Explanation: Equivalence partitioning
means designing a test case to detect the
error in a group or a class.

28. What are some common

testing tools for embedded
systems?
Explanation: Some common testing tools for
embedded systems are:

QTP (Quick Test Professional)

LoadRunner
WinRunner
Silk Test
TestDirector

29. In embedded systems, how

does a combination of functions
minimise memory requirements?
Explanation: The amount of code that
needs to be dealt with is decreased, which
reduces overhead, and redundancy is
removed if the functions have anything in
common.

Another feature that is optimised is memory

allocation, and it makes sense to group a set
of functions that are related in some way as
a single unit rather than having them
distributed across the programme.

30. How does using a local

variable's address lead to less-
than-optimal code?
Explanation: Register allocation is the
compiler's most effective optimization. That
is, it uses the register to manipulate the
variable before using a memory.
Local variables are often assigned in
registers. The compiler won't assign a local
variable to a register, though, if we take its
address.

With this, we come to an end for the top

embedded interview questions and
answers.

Also see, Html interview questions

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Frequently
Asked Questions

How do I prepare for an

embedded interview?
You can prepare for an embedded interview
by focusing on microcontroller
programming, real-time systems, and
embedded C. Understand hardware-
software interaction and practice problem-
solving with embedded systems concepts.

What are two examples of

embedded systems?
Examples include a car's Engine Control Unit
(ECU) for managing engine functions and a
smart thermostat regulating home
temperature.

What is the purpose of an

embedded interview?
The purpose of an embedded interview to
assess candidates' understanding of
embedded systems, hardware-software
interactions, programming skills, and
problem-solving abilities to ensure
suitability for roles in embedded systems
development.

What is the use of @embedded?

In programming, @embedded is not a