Micro Processor Interview Online Test
Technical interview questions and answers are essential for Micro Processor Interviews because companies want to evaluate your understanding of CPU architecture, instruction sets, registers, addressing modes, interrupts, and memory hierarchy. Microprocessor fundamentals are crucial for electronics, embedded systems, and computer engineering interviews. Companies like TCS, Infosys, Wipro, Cognizant, and Capgemini frequently include microprocessor questions in placement tests and technical rounds. This guide provides the most important Micro Processor interview questions with clear explanations to help freshers and engineering students strengthen their basics. Preparing these questions will boost your confidence during hardware-related interviews, lab-oriented assessments, and competitive exams.
1. What are the various registers in 8085?
Answer: Accumulator register, Temporary register, Instruction register, Stack Pointer, Program Counter are the various registers in 8085 .
Show Answer
Hide Answer
2. In 8085 name the 16 bit registers?
Answer: Stack pointer and Program counter all have 16 bits.
Show Answer
Hide Answer
3. What is Stack Pointer?
Answer: Stack pointer is a special purpose 16-bit register in the Microprocessor, which holds the address of the top of the stack.
Show Answer
Hide Answer
4. What is Program counter?
Answer: Program counter holds the address of either the first byte of the next instruction to be fetched for execution or the address of the next byte of a multi byte instruction, which has not been completely fetched. In both the cases it gets incremented automatically one by one as the instruction bytes get fetched. Also Program register keeps the address of the next instruction.
Show Answer
Hide Answer
5. Which Stack is used in 8085?
Answer: LIFO (Last In First Out) stack is used in 8085.In this type of Stack the last stored information can be retrieved first.
Show Answer
Hide Answer
6. What happens when HLT instruction is executed in processor?
Answer: The Micro Processor enters into Halt-State and the buses are tri-stated.
Show Answer
Hide Answer
7. What is meant by a bus?
Answer: A bus is a group of conducting lines that carriers data, address, & control signals.
Show Answer
Hide Answer
8. What is Tri-state logic?
Answer: Three Logic Levels are used and they are High, Low, High impedance state. The high and low are normal logic levels & high impedance state is electrical open circuit conditions. Tri-state logic has a third line called enable line.
Show Answer
Hide Answer
9. Give an example of one address microprocessor?
Answer: is a one address microprocessor.
Show Answer
Hide Answer
10. In what way interrupts are classified in 8085?
Answer: In 8085 the interrupts are classified as Hardware and Software interrupts.
Show Answer
Hide Answer
12. What are Software interrupts?
Answer: RST0, RST1, RST2, RST3, RST4, RST5, RST6, RST7.
Show Answer
Hide Answer
14. Name 5 different addressing modes?
Answer: Immediate, Direct, Register, Register indirect, Implied addressing modes.
Show Answer
Hide Answer
16. What is clock frequency for 8085?
Answer: 3 MHz is the maximum clock frequency for 8085.
Show Answer
Hide Answer
19. What are input & output devices?
Answer: Keyboards, Floppy disk are the examples of input devices. Printer, LED / LCD display, CRT Monitor are the examples of output devices.
Show Answer
Hide Answer
20. Can an RC circuit be used as clock source for 8085?
Answer: Yes, it can be used, if an accurate clock frequency is not required. Also, the component cost is low compared to LC or Crystal.
Show Answer
Hide Answer
21. Why crystal is a preferred clock source?
Answer: Because of high stability, large Q (Quality Factor) & the frequency that doesnt drift with aging. Crystal is used as a clock source most of the times.
Show Answer
Hide Answer
22. Which interrupt is not level-sensitive in 8085?
Answer: - RST 7.5 is a raising edge-triggering interrupt.
Show Answer
Hide Answer
24. What are level-triggering interrupt?
Answer: RST 6.5 & RST 5.5 are level-triggering interrupts
Show Answer
Hide Answer
25. What are the flags in 8086?
Answer: In 8086 Carry flag, Parity flag, Auxiliary carry flag, Zero flag, Overflow flag, Trace flag, Interrupt flag, Direction flag, and Sign flag.
Show Answer
Hide Answer
28. Which interrupts are generally used for critical events?
Answer: - Non-Maskable interrupts are used in critical events. Such as Power failure, Emergency, Shut off etc.,
Show Answer
Hide Answer
29. Give examples for Maskable interrupts?
Answer: RST 7.5, RST6.5, RST5.5 are Maskable interrupts
Show Answer
Hide Answer
30. Give example for NonMaskable interrupts?
Answer: Trap is known as NonMaskable interrupts, which is used in emergency condition.
Show Answer
Hide Answer
31. What is the Maximum clock frequency in 8086?
Answer: 5 Mhz is the Maximum clock frequency in 8086.
Show Answer
Hide Answer
32. What are the various segment registers in 8086?
Answer: Code, Data, Stack, Extra Segment registers in 8086.
Show Answer
Hide Answer
33. Which Stack is used in 8086?
Answer: FIFO (First In First Out) stack is used in 8086.In this type of Stack the first stored information is retrieved first.
Show Answer
Hide Answer
34. What is SIM and RIM instructions?
Answer: SIM is Set Interrupt Mask. Used to mask the hardware interrupts. RIM is Read Interrupt Mask. Used to check whether the interrupt is Masked or not.
Show Answer
Hide Answer
35. Which is the tool used to connect the user and the computer?
Answer: Interpreter is the tool used to connect the user and the tool.
Show Answer
Hide Answer
36. What is the position of the Stack Pointer after the PUSH instruction?
Answer: The address line is 02 less than the earlier value.
Show Answer
Hide Answer
37. What is the position of the Stack Pointer after the POP instruction?
Answer: The address line is 02 greater than the earlier value.
Show Answer
Hide Answer
38. Logic calculations are done in which type of registers?
Answer: Accumulator is the register in which Arithmetic and Logic calculations are done.
Show Answer
Hide Answer
39. What are the different functional units in 8086?
Answer: Bus Interface Unit and Execution unit, are the two different functional units in 8086.
Show Answer
Hide Answer
40. Give examples for Micro controller?
Answer: Z80, Intel MSC51 &96, Motorola are the best examples of Microcontroller.
Show Answer
Hide Answer
41. What is meant by crosscompiler?
Answer: A program runs on one machine and executes on another is called as crosscompiler.
Show Answer
Hide Answer
42. Which Segment is used to store interrupt and subroutine return address registers?
Answer: Stack Segment in segment register is used to store interrupt and subroutine return address registers.
Show Answer
Hide Answer
43. Which Flags can be set or reset by the programmer and also used to control the operation of the processor?
Answer: Trace Flag, Interrupt Flag, Direction Flag.
Show Answer
Hide Answer
44. What does EU do?
Answer: Execution Unit receives program instruction codes and data from BIU, executes these instructions and store the result in general registers.
Show Answer
Hide Answer
45. Which microprocessor accepts the program written for 8086 without any changes?
Answer: 8088 is that processor.
Show Answer
Hide Answer
46. What is the difference between 8086 and 8088?
Answer: The BIU in 8088 is 8bit data bus & 16 bit in 8086.Instruction queue is 4 byte long in 8088and 6 byte in 8086.
Show Answer
Hide Answer
47. In 8085 which is called as High order / Low order Register?
Answer: Flag is called as Low order register & Accumulator is called as High order Register.
Show Answer
Hide Answer