Embedded System Interview Questions

1. What is an Embedded System? Give some examples of embedded system in daily life.

Ans. Embedded System is a system which hides a small computation unit
inside. This computer is not general purpose computer like our Desktop PC but a
small microcontroller or microprocessor. Embedded System is designed to
perform specific tasks. Best example of an Embedded System is our mobile
phone which includes a processing unit or no. of processing units along with
peripherals like keypad/touchpad, touch screen, LCD, Communication modules
etc.
There are other examples like Electronic System in washing machine, ATM
machine, front panel of Microwave oven, printers, TV, set top boxes, Remote
control, Dashboard of a 4-wheeler and many more. If you observe carefully we
are surrounded by a no. of embedded system and use them very frequently in
our day to day life.

2. What are basic features of an Embedded System?

A good embedded system must possess following features…
Microcontroller based
Software driven
Reliable
Real time control system
Autonomous and human interactive
Operating on diverse physical variables
Operating in diverse environments

3. What are various categories of an Embedded System based on
complexity?

Ans. Embedded Systems can be broadly classified in three categories…
a. Small Scale – 8/16 bit CPU, little hardware, less software
complexity, no RTOS, battery operated.
b. Medium scale – 16/32 bit uC or DSPs, Complex hardware and
software design, RTOS source code engg tool, IDE.
c. Sophisticated – Configurable processors, Cutting edge applications,
highly complex hardware and software design

4. Why PC can’t be treated as an Embedded System?

Ans. Of course PC is also embedded with a processing unit but still it can not be
called as an Embedded System. The reason is very clear that PC is not supposed
to do a specific task. For a bank employee PC is accountings add for his work
while for an engineer it is designs add. For a doctor PC helps to analyze patient
reports and for children it’s more like video game or a communication system to
stay connected with their friends through social networking websites. Hence PC
has different applications for different people; hence it cannot be treated as an
embedded system.

5. What is difference between a PC based System and an
Embedded System?

Ans. A PC based system is bulky hence difficult to be deployed specially in
remote areas. For example if one wants a data logger system to monitor all the
processes and events in an aircraft or on a hilly area, PC is never a suitable
option. In this case an Embedded System can do the job well consuming very
small space. Also PC based system are not so cost efficient and as reliable as
embedded systems.

6. If embedded systems are so important and popular than why PCs still exist, why can’t we use embedded systems instead of PCs?

Ans. Well PC works with operating systems and they support comprehensive
cross compilers for generating executable files for embedded systems. Hence we
can never ignore the importance of PCs

7. What are the main components of an Embedded System?

Ans. Components of an embedded system depends on the application it is
intended to perform. Generally an embedded system contains sensors,
processor(s) and actuators. Main components of an embedded system are
Processor, Memory, Peripherals like Keypad, LCD etc.
We can classify these components in three categories
a. Hardware includes sensors, actuators, Processor, RAM, ROM,
ADC, DAC, Timers, Ports etc.
b. Software includes System software and Application software. A
system software can be a scheduler or an RTOS (Real Time
Operating System).
c. Firmware responsible for running hardware components like disk
drivers, protocol gateways etc.

8. What’s difference between a microcontroller and microprocessor?

Ans. Microcontroller has a CPU along with various peripherals like timers,
I/Os, Serial communication modules, Memory etc integrated on a single chip
while microprocessor doesn’t. It has to be connected will all these externally as
Microprocessor just has a CPU core on a chip.

9.If microcontroller is so powerful then why don’t they use a microcontroller instead of microprocessor for desktops and laptops?

Ans. Actually in Desktop PCs and Laptops space efficiency is not as important
as in mobile phones or other handy gadgets. Also much is expected from a
Desktop or Laptop hence it’s better to integrate highly efficient processor in
terms of speed and data handling capability with peripherals outside the chip i.e.
on a mother board.

10. What’s difference between Harvard and Von Neumann
architecture?

Ans. In Von Neumann architecture instructions and data are stored together in
a common memory space while in Harvard they are stored separately.
Harvard architecture has separate data and instruction busses, allowing
transfers to be performed simultaneously on both busses. Von Neumann
architecture or Princeton architecture has only one bus which is used for
both data transfers and instruction fetches, and therefore data transfers and
instruction fetches must be scheduled – they cannot be performed at the same
time.

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