This section contains more frequently asked Microprocessors 8085 Questions Bank with Answers in the various University Level and Competitive Examinations.


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1. If the crystal oscillator is operating at 15 MHz, the PCLK output of 8284 is

  • 2.5 MHz.
  • 5 MHz.
  • 7.5 MHz.
  • 10 MHz.

2. In which T-state does the CPU sends the address to memory or I/O and the ALE signal for demultiplexing

  • T1.
  • T2.
  • T3.
  • T4.

3. If a 1M ×1 DRAM requires 4 ms for a refresh and has 256 rows to be refreshed, no more than __________ of time must pass before another row is refreshed.

  • 64 ms.
  • 4 ns.
  • 0.5 ns.
  • 15.625 µs .

4. In a DMA write operation the data is transferred

  • from I/O to memory.
  • from memory to I/O.
  • from memory to memory.
  • from I/O to I/O.

5. Which type of JMP instruction assembles if the distance is 0020 h bytes

  • near.
  • far
  • short
  • none of the above.

6. A certain SRAM has CS = 0 , WE = 0 and OE = 1. In which of the following modes this SRAM is operating

  • Read
  • Write
  • Stand by
  • None of the above

7. Which of the following is true with respect to EEPROM?

  • contents can be erased byte wise only.
  • contents of full memory can be erased together
  • contents can be erased using ultra violet rays
  • contents can not be erased

8. Pseudo instructions are basically

  • false instructions.
  • instructions that are ignored by the microprocessor
  • assembler directives
  • instructions that are treated like comments

9. Number of the times the instruction sequence below will loop before coming out of loop is MOV AL, 00h A1: INC AL JNZ A1

  • 0
  • 1
  • 255
  • 256

10. What will be the contents of register AL after the following has been executed MOV BL, 8C MOV AL, 7E ADD AL, BL

  • 0A and carry flag is set
  • 0A and carry flag is reset
  • 6A and carry flag is set
  • 6A and carry flag is reset
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