Microcontroller Questions and Answers Part-1

1. A microcontroller at-least should consist of:
a) RAM, ROM, I/O ports and timers
b) CPU, RAM, I/O ports and timers
c) CPU, RAM, ROM, I/O ports and timers
d) CPU, ROM, I/O ports and timers

Answer: c
Explanation: A microcontroller at-least consists of a processor as its CPU with RAM, ROM, I/O ports and timers. It may contain some additional peripherals like ADC, PWM, etc.

2. Unlike microprocessors, microcontrollers make use of batteries because they have:
a) high power dissipation
b) low power consumption
c) low voltage consumption
d) low current consumption

Answer: b
Explanation: Micro Controllers are made by using the concept of VLSI technology. So here, CMOS based logic gates are coupled together by this technique that consumes low power.

3. What is the order decided by a processor or the CPU of a controller to execute an instruction?
a) decode,fetch,execute
b) execute,fetch,decode
c) fetch,execute,decode
d) fetch,decode,execute

Answer: d
Explanation: First instruction is fetched from Program Memory. After fetching, instruction is decoded to generate control signals to perform the intended task. After decoding, instruction is executed and the complete intended task of that particular instruction.

4. If we say microcontroller is 8-bit then here 8-bit denotes size of:
a) Data Bus
b) ALU
c) Control Bus
d) Address Bus

Answer: b
Explanation: If we say a microcontroller is 8-bit it means that it is capable of processing 8-bit data at a time. Data processing is the task of ALU and if ALU is able to process 8-bit data then the data bus should be 8-bit wide. In most books it tells that size of data bus but to be precise it is the size of ALU because in Harvard Architecture there are two sets of data bus which can be of same size but it is not mandatory.

5. How are the performance and the computer capability affected by increasing its internal bus width?
a) it increases and turns better
b) it decreases
c) remains the same
d) internal bus width doesn’t affect the performance in any way

Answer: a
Explanation: As the bus width increases, the number of bits carried by bus at a time increases as a result of which the total performance and computer capability increases.

6. Abbreviate CISC and RISC.
a) Complete Instruction Set Computer, Reduced Instruction Set Computer
b) Complex Instruction Set Computer, Reduced Instruction Set Computer
c) Complex Instruction Set Computer, Reliable Instruction Set Computer
d) Complete Instruction Set Computer, Reliable Instruction Set Computer

Answer: b
Explanation: CISC means Complete Instruction Set Computer because in this a microcontroller has an instruction set that supports many addressing modes for the arithmetic and logical instructions, data transfer and memory accesses instructions. RISC means Reduced Instruction Set Computer because here a microcontroller has an instruction set that supports fewer addressing modes for the arithmetic and logical instructions and for data transfer instructions.

7. Give the names of the buses present in a controller for transferring data from one place to another?
a) data bus, address bus
b) data bus
c) data bus, address bus, control bus
d) address bus

Answer: c
Explanation: There are 3 buses present in a microcontroller they are data bus (for carrying data from one place to another), address bus (for carrying the address to which the data will flow) and the control bus (which tells the controller to execute which type of work at that address may be it read or write operation).

8. What is the file extension that is loaded in a microcontroller for executing any instruction?
a) .doc
b) .c
c) .txt
d) .hex

Answer: d
Explanation: Microcontrollers are loaded with .hex extension as they understand the language of 0’s and 1’s only.

9. What is the most appropriate criterion for choosing the right microcontroller of our choice?
a) speed
b) availability
c) ease with the product
d) all of the mentioned

Answer: d
Explanation: For choosing the right microcontroller for our product we must consider its speed so that the instructions may be executed in the least possible time. It also depends on the availability so that the particular product may be available in our neighboring regions or market in our need. It also depends on the compatibility with the product so that the best results may be obtained.

10. Why microcontrollers are not called general purpose computers?
a) because they have built in RAM and ROM
b) because they design to perform dedicated task
c) because they are cheap
d) because they consume low power

Answer: b
Explanation: Microcontrollers are designed to perform dedicated tasks. While designing general purpose computers end use is not known to designers.