ECE - MC - MICROCONTROLLER MCQ QUESTIONS - MC MCQ QUESTIONS
### ✅ **UNIT I: ARCHITECTURE OF 8051 MICROCONTROLLER (20 MCQs)**
1. **Which company developed the 8051 microcontroller?**
A) Intel
B) Motorola
C) AMD
D) Atmel
**Answer: A**
2. **8051 is a \_\_\_\_ bit microcontroller.**
A) 4
B) 8
C) 16
D) 32
**Answer: B**
3. **Microprocessor vs Microcontroller: Which has on-chip memory and I/O ports?**
A) Microprocessor
B) Microcontroller
C) Both
D) None
**Answer: B**
4. **Which block controls the sequence of execution in 8051?**
A) ALU
B) Timer
C) Program Counter
D) RAM
**Answer: C**
5. **The ALU in 8051 is responsible for:**
A) Memory addressing
B) Logical and arithmetic operations
C) Communication
D) Program storage
**Answer: B**
6. **How many I/O ports does the 8051 have?**
A) 2
B) 3
C) 4
D) 5
**Answer: C**
7. **Total number of pins in 8051 DIP package is:**
A) 20
B) 30
C) 40
D) 44
**Answer: C**
8. **PSW register in 8051 stands for:**
A) Program Status Word
B) Primary Status Window
C) Program Stack Width
D) Processor Status Word
**Answer: A**
9. **Which register is incremented automatically during program execution?**
A) PSW
B) PC
C) Stack Pointer
D) ACC
**Answer: B**
10. **What is the function of the Stack in 8051?**
A) Handles I/O operations
B) Stores immediate data
C) Temporary storage during interrupts
D) Controls timers
**Answer: C**
11. **Special Function Registers (SFRs) are located in which memory area?**
A) ROM
B) External RAM
C) Internal RAM
D) Code memory
**Answer: C**
12. **Which port is used to interface external memory?**
A) P0 and P2
B) P1 and P3
C) P2 and P3
D) P0 and P1
**Answer: A**
13. **The timer in 8051 is used for:**
A) RAM expansion
B) I/O programming
C) Delay generation
D) Address decoding
**Answer: C**
14. **Which of the following is NOT a feature of 8051?**
A) Serial port
B) Timers
C) Multiplication instruction
D) 32-bit ALU
**Answer: D**
15. **Interrupts in 8051 are used for:**
A) Resetting memory
B) Parallel processing
C) Handling events
D) Timer reset
**Answer: C**
16. **How many interrupts are there in 8051?**
A) 3
B) 4
C) 5
D) 6
**Answer: D**
17. **Port 0 of 8051 can be used as:**
A) Output only
B) Input only
C) Bidirectional I/O
D) Serial communication
**Answer: C**
18. **Which register indicates current status of ALU operations?**
A) PSW
B) PC
C) ACC
D) DPTR
**Answer: A**
19. **Which of the following is used for serial communication?**
A) Timer
B) Port 0
C) UART
D) Port 1
**Answer: C**
20. **External memory is accessed using which signal?**
A) ALE
B) PSEN
C) EA
D) All of the above
**Answer: D**
### ✅ **UNIT II: 8051 INSTRUCTION SET AND PROGRAMMING (20 MCQs)**
1. **Which instruction is used to transfer data from one register to another in 8051?**
A) MOV
B) ADD
C) SUBB
D) CJNE
**Answer: A**
2. **The instruction `ADD A, R1` performs:**
A) Subtraction
B) Multiplication
C) Addition of accumulator and R1
D) None
**Answer: C**
3. **Which instruction is used to jump unconditionally in 8051?**
A) SJMP
B) CJNE
C) JNC
D) JZ
**Answer: A**
4. **Which instruction is used to multiply two numbers?**
A) ADD
B) MUL AB
C) SUBB
D) DIV AB
**Answer: B**
5. **Logical instruction `ANL A, R2` performs:**
A) Logical OR
B) Logical AND
C) Logical XOR
D) Logical NOT
**Answer: B**
6. **Which instruction is used to compare two values and jump if not equal?**
A) JZ
B) CJNE
C) MOV
D) SJMP
**Answer: B**
7. **The maximum size of the immediate data in 8051 is:**
A) 4 bits
B) 8 bits
C) 12 bits
D) 16 bits
**Answer: B**
8. **Which instruction divides the accumulator by register B?**
A) DIV AB
B) SUB AB
C) MUL AB
D) MOV AB
**Answer: A**
9. **The instruction `CLR A` does what?**
A) Clears Port A
B) Clears all bits of the accumulator
C) Clears memory
D) Clears flag
**Answer: B**
10. **The bit manipulation instruction used to complement a bit is:**
A) SETB
B) CLR
C) CPL
D) MOV
**Answer: C**
11. **Instruction `MOVX` is used for:**
A) External memory access
B) Bit manipulation
C) Arithmetic operation
D) Logical operation
**Answer: A**
12. **How many addressing modes are available in 8051?**
A) 2
B) 4
C) 5
D) 6
**Answer: D**
13. **In which addressing mode is the operand specified within the instruction?**
A) Register
B) Immediate
C) Indirect
D) Direct
**Answer: B**
14. **`MOV A, #55H` is an example of:**
A) Direct addressing
B) Immediate addressing
C) Register indirect addressing
D) Relative addressing
**Answer: B**
15. **Time delay routines in 8051 are created using:**
A) Timers only
B) Loops and NOPs
C) Interrupts
D) UART
**Answer: B**
16. **To add two 16-bit numbers in 8051, you need to:**
A) Use ADD instruction twice with carry
B) Use only one ADD
C) Use MOV
D) Use NOP
**Answer: A**
17. **Which instruction checks if a bit is 1 and skips the next instruction if false?**
A) JB
B) JNB
C) JZ
D) JC
**Answer: A**
18. **Instruction `DJNZ` is used for:**
A) Delay creation
B) Decrement and jump if not zero
C) Compare and jump
D) Bit clearing
**Answer: B**
19. **BCD to HEX conversion is commonly done using:**
A) MOV & ADD
B) Logical and arithmetic instructions
C) Timers
D) Interrupts
**Answer: B**
20. **To find the smallest number among given values in assembly, we use:**
A) Compare and conditional jump
B) MUL AB
C) INC
D) PUSH and POP
**Answer: A**
### ✅ **UNIT III: PERIPHERALS OF 8051 (20 MCQs)**
1. **Which of the following ports of 8051 is used for interrupt and serial communication?**
A) Port 0
B) Port 1
C) Port 2
D) Port 3
**Answer: D**
2. **Each I/O port of 8051 is of size:**
A) 4-bit
B) 6-bit
C) 8-bit
D) 16-bit
**Answer: C**
3. **The address range of SFRs is:**
A) 00H to FFH
B) 00H to 7FH
C) 80H to FFH
D) 00H to 0FH
**Answer: C**
4. **Which port requires external pull-up resistors in 8051?**
A) Port 0
B) Port 1
C) Port 2
D) Port 3
**Answer: A**
5. **Bit addressable area of 8051 starts from:**
A) 00H
B) 20H
C) 30H
D) 80H
**Answer: B**
6. **Which instruction is used to set a single bit in I/O port?**
A) SETB
B) MOV
C) CLR
D) CPL
**Answer: A**
7. **Timer 0 and Timer 1 in 8051 are:**
A) 4-bit
B) 8-bit
C) 16-bit
D) 32-bit
**Answer: C**
8. **How many timer/counters are present in 8051?**
A) 1
B) 2
C) 3
D) 4
**Answer: B**
9. **Which SFR is used to control timer mode?**
A) TMOD
B) TCON
C) PCON
D) IE
**Answer: A**
10. **Timer Mode 2 in 8051 is:**
A) 13-bit
B) 16-bit
C) 8-bit auto-reload
D) 32-bit
**Answer: C**
11. **SBUF is used for:**
A) Bit manipulation
B) Serial communication
C) Stack operations
D) Timer operation
**Answer: B**
12. **8051 uses which standard for serial communication?**
A) USB
B) RS232
C) SPI
D) I2C
**Answer: B**
13. **The register that holds the baud rate settings is:**
A) TMOD
B) TH1
C) IE
D) TCON
**Answer: B**
14. **Which instruction is used to transmit data via serial port?**
A) MOV SBUF, A
B) MOV A, SBUF
C) SETB TI
D) CLR RI
**Answer: A**
15. **The TI flag is set when:**
A) A timer overflows
B) A bit is set
C) A byte is transmitted
D) An interrupt occurs
**Answer: C**
16. **8051 has how many interrupt sources?**
A) 2
B) 3
C) 5
D) 6
**Answer: D**
17. **Which interrupt has the highest priority by default?**
A) Serial
B) External 0
C) Timer 0
D) Timer 1
**Answer: B**
18. **The IE register is used to:**
A) Enable or disable interrupts
B) Configure timers
C) Clear the accumulator
D) Set the serial baud rate
**Answer: A**
19. **Which pin of 8051 is used for external interrupt 0?**
A) P3.3
B) P3.2
C) P3.4
D) P3.5
**Answer: B**
20. **Which register controls interrupt priority?**
A) IE
B) IP
C) PSW
D) PCON
**Answer: B**
### ✅ **UNIT IV: INTERFACING TECHNIQUES (20 MCQs)**
1. **Which IC is used for parallel peripheral interfacing with 8051?**
A) 8251
B) 8253
C) 8255
D) 8279
**Answer: C**
2. **How many ports are there in 8255?**
A) 1
B) 2
C) 3
D) 4
**Answer: C**
3. **How many modes are supported by 8255?**
A) 1
B) 2
C) 3
D) 4
**Answer: C**
4. **Which mode of 8255 is used for handshake input/output?**
A) Mode 0
B) Mode 1
C) Mode 2
D) BSR Mode
**Answer: B**
5. **Which mode allows bidirectional data transfer in 8255?**
A) Mode 0
B) Mode 1
C) Mode 2
D) BSR
**Answer: C**
6. **Relays are used to interface:**
A) Low power devices
B) High power AC/DC devices
C) Sensors
D) Microcontrollers
**Answer: B**
7. **Which component is used for temperature sensing?**
A) Relay
B) LM35
C) LCD
D) 8255
**Answer: B**
8. **Which display uses 7 segments to show digits?**
A) LCD
B) LED matrix
C) 7-segment display
D) OLED
**Answer: C**
9. **Which pin in 16x2 LCD selects command or data mode?**
A) VSS
B) RS
C) E
D) D4
**Answer: B**
10. **Which pin enables LCD operation?**
A) RS
B) RW
C) E
D) VSS
**Answer: C**
11. **Keyboard interfacing is based on:**
A) ADC
B) Matrix scanning
C) Timer
D) PWM
**Answer: B**
12. **How many rows and columns are there in 4x4 keypad?**
A) 2 rows, 2 columns
B) 4 rows, 4 columns
C) 8 rows
D) 3 rows, 4 columns
**Answer: B**
13. **Stepper motor rotates in:**
A) Continuous mode
B) Discrete steps
C) Random angle
D) Vibration
**Answer: B**
14. **Which is used to convert analog signal to digital?**
A) DAC
B) PWM
C) ADC
D) RTC
**Answer: C**
15. **Which component is used to interface analog output devices like speakers?**
A) ADC
B) DAC
C) LCD
D) LED
**Answer: B**
16. **PWM is generally used for controlling:**
A) Relays
B) Timers
C) DC motors
D) RAM
**Answer: C**
17. **What does PWM stand for?**
A) Pulse Width Memory
B) Pulse Wide Mode
C) Pulse Width Modulation
D) Programmable Wave Modulation
**Answer: C**
18. **The interface used to control AC loads safely is:**
A) Keyboard
B) DAC
C) Relay
D) LCD
**Answer: C**
19. **Which of these is NOT used for interfacing with 8051?**
A) LCD
B) ADC
C) Hard disk
D) Stepper motor
**Answer: C**
20. **Sensor interfacing involves conversion of:**
A) Analog to analog
B) Digital to analog
C) Analog to digital
D) None
**Answer: C**
### ✅ **UNIT V: ADVANCED MICROCONTROLLERS (20 MCQs)**
1. **Which of the following is an open-source microcontroller platform?**
A) 8051
B) ARM7
C) Arduino
D) PIC
**Answer: C**
2. **The Arduino Uno board is based on which microcontroller?**
A) AT89C51
B) ATmega328P
C) PIC16F877A
D) ATmega2560
**Answer: B**
3. **Which programming language is commonly used in Arduino IDE?**
A) Python
B) Java
C) C/C++
D) Assembly
**Answer: C**
4. **What type of port is used to upload code into Arduino?**
A) VGA
B) Ethernet
C) USB
D) HDMI
**Answer: C**
5. **What is the voltage level of digital I/O pins in Arduino Uno?**
A) 1.8V
B) 3.3V
C) 5V
D) 12V
**Answer: C**
6. **Which of the following is a feature of Arduino?**
A) Complex architecture
B) Needs external programmer
C) Open-source hardware
D) Cannot be used in IoT
**Answer: C**
7. **Which one is an IoT communication protocol?**
A) I2C
B) SPI
C) MQTT
D) USB
**Answer: C**
8. **Which of the following is not an IoT device?**
A) Smart thermostat
B) Smart light bulb
C) Manual switch
D) Smart watch
**Answer: C**
9. **In IoT, the purpose of a sensor is to:**
A) Control data
B) Generate software
C) Collect data
D) Transmit emails
**Answer: C**
10. **Which architecture is commonly used in IoT?**
A) 3-tier architecture
B) Von Neumann architecture
C) Harvard architecture
D) Client-Server architecture
**Answer: A**
11. **Which one of the following is a layer in IoT architecture?**
A) Application layer
B) Assembly layer
C) Programming layer
D) Compiler layer
**Answer: A**
12. **Which of the following technologies is used in smart homes?**
A) IoT
B) Robotics
C) Bioinformatics
D) Web designing
**Answer: A**
13. **What is the main use of actuators in IoT systems?**
A) Sensing temperature
B) Measuring humidity
C) Performing physical actions
D) Storing data
**Answer: C**
14. **Which of the following is an example of IoT service?**
A) Video calling
B) Smart irrigation
C) Text editing
D) Gaming
**Answer: B**
15. **Which component is not essential for a basic IoT system?**
A) Sensor
B) Internet
C) Actuator
D) Television
**Answer: D**
16. **What is the full form of IoT?**
A) Internet of Televisions
B) Interface of Technology
C) Internet of Things
D) Interlink of Transmission
**Answer: C**
17. **Which of the following is NOT a feature of Arduino?**
A) Easy to program
B) Cost-effective
C) Proprietary hardware
D) Open source
**Answer: C**
18. **What is one major ethical concern in IoT?**
A) Display resolution
B) Memory usage
C) Data privacy
D) Operating speed
**Answer: C**
19. **IoT is mostly used in which of the following sectors?**
A) Healthcare
B) Agriculture
C) Home automation
D) All of the above
**Answer: D**
20. **Which of the following can be a node in IoT network?**
A) Smartphone
B) Sensor
C) Microcontroller
D) All of the above
**Answer: D**
SYLLABUS
Unit I ARCHITECTURE OF 8051 MICROCONTROLLER
Microprocessor-Microcontroller-Comparison of Microprocessor and Microcontroller-Architecture diagram of Microcontroller 8051-Functions of each Block-Pin details of 8051-ALU-Special Function RegistersProgram Counter-PSW Register-Stack I/O Ports-Timer-Interrupt-Serial Port-External memory.
Unit II 8051 INSTRUCTION SET AND PROGRAMMING
Instruction set of 8051-Classification of 8051 Instructions-Data Transfer Instructions-Arithmetic Instructions-Logical InstructionsBranching Instructions-Bit Manipulation Instructions - Different Addressing Modes of 8051-Time Delay routines. Assembly Language Programs - 16 Bit Addition -8 Bit Multiplication - BCD to HEX Code Conversion- Smallest number.
Unit III PERIPHERALS OF 8051
I/O Ports - Bit Addresses for I/O Ports-I/O Port Programming-I/O bit Manipulation Programming. Timer/Counter - SFRS for Timer- Modes of Timers/countersProgramming 8051 Timer (Simple programs). Serial Communication - SFRs for Serial Communication-RS232 Standard-8051 Connection to RS 232-8051 Serial Port Programming Interrupts - 8051 Interrupts-SFRs for interrupt-Interrupt priority Interfacing Techniques
Unit IV INTERFACING TECHNIQUES
IC 8255-Block diagram-Modes of 8255-8051 interfacing with 8255 Interfacing - Relay interfacing- Sensor interfacing -Seven Segment LED Display Interfacing - LCD Interfacing-Keyboard Interfacing-Stepper Motor interfacing-ADC Interfacing- DAC interfacing - DC motor Interfacing using PWM.
Unit V ADVANCED MICROCONTROLLERS
Arduino- General Block diagram- Features-Applications IoT- Introduction to IoT-Architecture of IoT- IoT Services and Applications – IoT Ethics.
