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TWO MARK QUESTIONS - 8085 Microprocessor

1. What is Microprocessor? Give the power supply & clock frequency of 8085?

Ans:A microprocessor is a multipurpose, programmable logic device that reads binary instructions from a storage device called memory accepts binary data as input and processes data according to those instructions and provides result as output. The power supply of 8085 is +5V and clock frequency in 3MHz.

2. List few applications of microprocessor-based system.

Ans:   It is used:

i. For measurements, display and control of current, voltage, temperature, pressure, etc.
ii. For traffic control and industrial tool control.
iii. For speed control of machines.

3. What are the functions of an accumulator?

Ans:The accumulator is the register associated with the ALU operations and sometimes I/O operations. It is an integral part of ALU. It holds one of data to be processed by ALU. It also temporarily stores the result of the operation performed by the ALU.

4. List the 16 – bit registers of 8085 microprocessor.

Ans:Stack pointer (SP) and Program counter (PC).

5. List the allowed register pairs of 8085.

Ans:

  • B-C register pair
  • D-E register pair
  • H-L register pair

11. List out the five categories of the 8085 instructions. Give examples of the instructions for each group.

Ans:

  • Data transfer group – MOV, MVI, LXI.
  • Arithmetic group – ADD, SUB, INR.
  • Logical group –ANA, XRA, CMP.
  • Branch group – JMP, JNZ, CALL.
  • Stack I/O and Machine control group – PUSH, POP, IN, HLT.

12. Explain the difference between a JMP instruction and CALL instruction.

Ans: A JMP instruction permanently changes the program counter. A CALL instruction leaves information on the stack so that the original program execution sequence can be resumed.

13. Explain the purpose of the I/O instructions IN and OUT.

Ans: The IN instruction is used to move data from an I/O port into the accumulator. The OUT instruction is used to move data from the accumulator to an I/O port. The IN & OUT instructions are used only on microprocessor, which use a separate address space for interfacing.

14. What is the difference between the shift and rotate instructions?

Ans: A rotate instruction is a closed loop instruction. That is, the data moved out at one end is put back in at the other end. The shift instruction loses the data that is moved out of the last bit locations.

15. How many address lines in a 4096 x 8 EPROM CHIP?

Ans: 12 address lines.

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