8051 Microcontroller Interview Questions and Answers.

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8051 Micro controller Interview Questions and Answers for  Students.

Microcontroller Interview Questions

This article is predominantly centered around the most over and over asked and the most recent refreshed 8051 Microcontroller Interview Questions and Answers.

In the event that you are searching for “8051 Microcontroller Interview Questions “, you are at the ideal spot. Here I have attempted to make some assortment of “8051 Microcontroller Interview Questions with answers” that may ask by your questioner.

1.What is 8051 Microcontroller ?

The Intel 8051 microcontroller is perhaps the most well known universally useful microcontrollers being used today.It is a 8-bit group of microcontroller created by Intel in the year 1981.

This microcontroller was likewise alluded as “framework on a chip” since it has

  • 128 bytes of RAM,
  • 4Kbytes of ROM,
  • 2 Timers,
  • 1 Serial port,
  • and four ports on a single chip.

8051 microcontroller permits CPU to deal with 8bits of information at a time.n case the information is bigger than 8 pieces then it must be broken into parts so the CPU can measure advantageously.

2. What Is The Difference Between Harvard Architecture And Von Neumann Architecture?

Answer :

The name Harvard Architecture comes from the Harvard Mark. The most evident attribute of the Harvard Architecture is that it has actually separate signs and capacity for code and information memory.

It is conceivable to get to program memory and information memory all the while. Commonly, code (or program) memory is perused just and information memory is perused compose. In this manner, it is unthinkable for program substance to be changed by the actual program.

The von Neumann Architecture is named after the mathematician and early PC researcher John von Neumann. Von Neumann machines have shared signs and memory for code and information. Subsequently, the program can be effectively changed without help from anyone else since it is put away in read-compose memory.

3. 8051 was developed using which technology?


Intel’s unique MCS-51 family was created utilizing NMOS innovation, yet later forms, distinguished by a letter C in their name (e.g., 80C51) utilized CMOS innovation and devour less force than their NMOS archetypes. This made them more appropriate for battery-fueled gadgets.

4. Explain what is microcontroller?

The microcontroller is an independent framework with peripherals, memory and a processor that can be utilized as inserted framework.

5.Mention what is the difference between microprocessor and microcontroller?

Microchip is administrators of the assets (I/O, memory) which lie outside of its

Microcontroller have I/O, memory, and so on incorporated into it and explicitly intended for control

6. List out different employments of clocks in inserted framework?

Timers in embedded system are used in multiple ways

  • Real Time Clock (RTC) for the system
  • Initiating an event after a preset time delay
  • Initiating an even after a comparison of preset times
  • Capturing the count value in timer on an event
  • Between two events finding the time interval
  • Time slicing for various tasks
  • Time division multiplexing
  • Scheduling of various tasks in RTOS

7. Explain what is a Watchdog Timer?

A guard dog clock is an gadget or card that execute explicit activity after certain time-frame if something turns out badly with an electronic framework.

8. What are The Features Of 8051 Microcontroller?

Answer :

  • 40 Pin IC.
  • 128 bytes of RAM.
  • 4K ROM.
  • 2 Timers (Timer 0 and Timer 1).
  • 32 Input/Output pins.
  • 1 sequential port.
  • 6 Interrupts (Including Reset).

9. What Are The Types Of Interrupts In 8051?

Answer :

  • Outer interfere with 0 (IE0) has most noteworthy need among interrupts.
  • Clock interfere with 0 (TF0)
  • Outer intrude on 1 (IE1)
  • Clock interfere with 1 (TF1) has least need among different interrupts.
  • Sequential port Interrupt
  • Reset.

10. What Are The Four Distinct Types Of Memory In 8051?

Answer :

  • Internal RAM
  • Special function registers
  • Program memory
  • External data memory

11. Which interrupt has highest priority in Microcontroller ?

Trap interrupt has the highest priority.A trap is an abnormal condition detected by the CPU, which indicates an unknown I/O device is accessed, etc

12.What is an Interrupt administration routine in Microcontroller?

At the point when Microcontroller is under abrupt interfere with, it will call ISR (Interrupt administration schedule) that will store the location of current memory address and takes the control to new intrude on memory address. After the intrude on, the control will move back to its past address.

13.List some 8051 Microcontroller applications in embedded systems ?

The uses of 8051 Microcontroller is associated with 8051 based tasks. The following are the rundown of 8051 tasks .

  • Managed High Sensitive based Power Saver for Street Light Control System
  • The Temperature Humidity Monitoring System of Soil Based on Wireless Sensor Networks utilizing
  • RFID based Electronic Passport System for Easy Governance utilizing
  • based DC Motor Speed Control
  • Based Line Following Robot
  • Zigbee based Automatic Meter Reading System
  • GSM based Electricity Energy Meter Billing with Onsite Display
  • Android Phone Speech Recognition Sensed Voice Command based Notice Board Display
  • Stopping Availability Indication System
  • Voice Controlled Home Appliances
  • based RFID Sensed Device Access
  • Controller Home Appliances
  • PC Mouse worked Electrical Load Control Using VB Application
  • Sun oriented Highway Lighting System with Auto Turn Off in Daytime
  • 8051 Microcontroller based Wireless Energy Meter
  • Rancher Friendly Solar Based Electric Fence for Deterring Cattles
  • Vehicle Movement Sensed Streetlight with Daytime auto off Features

14. How much total external data memory that can be interfaced to the 8051?


64K information memory (Because PC-16bits)

15. What are Special Function Registers (SFR)?


The 8051 gives 128 bytes of memory (80H to 0FFH) for Special Function Registers (SFRs). SFRs are digit, byte, or word-sized registers that are utilized to control clocks, counters, sequential I/O, port I/O, and peripherals.

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