MCQs on Microprocessor

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01․ Both the ALU and control section of CPU employ which special purpose storage location?
Buffers
Decoders
Accumulators
Registers

Accumulator is a special purpose 8-bit register which is used as a storage for almost all arithmetic and logic operations.
02․ IN an intel 8085A microprocessor, why is READY signal used?
To indicate to user that the microprocessor is working and is ready for use.
To provide proper WAIT states when the microprocessor is communicating with a slow peripheral device.
To slow down a fast peripheral device so as to communicate at the microprocessor’s device.
None of the above.

Ready signal is used in microprocessor to communicate with slow peripheral device. It provides proper synchronization between processor and slow devices.
03․ Assertion(A): Monostablemultivibrators (IC74121) are used in a microprocessor based system for frequency measurement. Reason(R): Microprocessor counts the number of interrupt signals/second or within a specified interval through ISR.
Both A & R are true and R is the correct explanation of A.
Both A & R are true but R is not the correct explanation of A.
A is true but R is false.
A is false but R is true.

IC74121 is used for frequency measurement in microprocessor and microprocessor counts the number of interrupt signals/second or within a specified interval through ISR.
04․ Consider the following I) Sign flag II) Trap flag III) Parity flag IV) Auxiliary carry flag. Which one of the above flags is/are present in 8085 microprocessor?
(I) only
(I) & (II)
(II) & (III)
(I) ,(III) & (IV)

Trap flag is not present in 8085 microprocessor.
05․ Consider the following statements: In 8085 microprocessor, data-bus and address bus are multiplexed in order to I)Increase the speed of microprocessor. II)Reduce the number of pins. III)Connect more peripheral chips. Which of these statements is/are correct?
(I) only
(II) only
(II) & (III)
(I), (II) & (III)

Lower byte of address bus (A0 - A7) are multiplexed with data bus (AD0 - AD7) to reduce the number of pins of microprocessor. This multiplexed address is controlled by ALE signal.
06․ Assertion(A): Address bus is unidirectional. Reason(R): Data bus is bidirectional
Both A & R are true and R is the correct explanation of A
Both A & R are true but R is not the correct explanation of A
A is true but R is false
A is false but R is true

Address bus is unidirectional and data bus is bidirectional.
07․ Assertion(A): The frequency of 8085 system is ½ of the crystal frequency. Reason(R): Microprocessor (8085) requires a two phase clock.
Both A & R are true and R is the correct explanation of A
Both A & R are true but R is not the correct explanation of A
A is true but R is false
A is false but R is true

Microprocessor clock frequency = (Crystal frequency/2)
08․ ALU (Arithmetic and Logic Unit ) of 8085 microprocessor consists of
Accumulator, temporary register, arithmetic and logic circuits
Accumulator, arithmetic, logic circuits and five flags
Accumulator, arithmetic and logic circuits
Accumulator, temporary register, arithmetic, logic circuits and five flags

ALU consists of Accumulator, temporary register, arithmetic, logic circuits and five flags.
09․ Which components are NOT found on chip in a microprocessor but may be found on chip in a microcontroller?
SRAM & USART
EPROM & PORTS
EPROM, USART & PORTS
SRAM, EPROM & PORTS

EPROM, USART & PORTS are found on chip in microcontroller but not in microprocessor chip.
10․ The clock speed of 8085 is
1MHz.
1KHz.
3.2KHz.
3.2MHz.

8085 requires a signal +5V power supply and operates at 3.2 MHZ single phase clock.
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