What is a Microprocessor?
Microprocessor is a program-controlled device, which fetches the instructions from memory, decodes and executes the instructions. Most Micro Processor are single- chip devices.
What are the flags in 8086?
In 8086 Carry flag, Parity flag, Auxiliary carry flag, Zero flag, Overflow flag, Trace flag, Interrupt flag, Direction flag, and Sign flag.
Why crystal is a preferred clock source?
Because of high stability, large Q (Quality Factor) & the frequency that doesn’t drift with aging. Crystal is used as a clock source most of the times.
In 8085 which is called as High order / Low order Register?
Flag is called as Low order register & Accumulator is called as High order Register.
What is Tri-state logic?
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.
What happens when HLT instruction is executed in processor?
The Micro Processor enters into Halt-State and the buses are tri-stated.
Which Stack is used in 8085?
LIFO (Last In First Out) stack is used in 8085.In this type of Stack the last stored information can be retrieved first
What is Program counter?
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.
What are the various registers in 8085?
Accumulator register, Temporary register, Instruction register, Stack Pointer, Program Counter are the various registers in 8085
What’s the speed and device maximum specs for Firewire?
IEEE 1394 (Firewire) supports the maximum of 63 connected devices with speeds up to 400 Mbps. Where’s MBR located on the disk? Main Boot Record is located in sector 0, track 0, head 0, cylinder 0 of the primary active partition.
Where does CPU Enhanced mode originate from?
Intel’s 80386 was the first 32-bit processor, and since the company had to backward-support the 8086. All the modern Intel-based processors run in the Enhanced mode, capable of switching between Real mode (just like the real 8086) and Protected mode, which is the current mode of operation.
How many bit combinations are there in a byte?
Byte contains 8 combinations of bits.
Have you studied buses? What types?
There are three types of buses.
Address bus: This is used to carry the Address to the memory to fetch either Instruction or Data.
Data bus : This is used to carry the Data from the memory.
Control bus : This is used to carry the Control signals like RD/WR, Select etc.
What is the Maximum clock frequency in 8086?
5 Mhz is the Maximum clock frequency in 8086.
What is meant by Maskable interrupts?
An interrupt that can be turned off by the programmer is known as Maskable interrupt.
What is Non-Maskable interrupts?
An interrupt which can be never be turned off (ie. disabled) is known as Non-Maskable interrupt
What are the different functional units in 8086?
Bus Interface Unit and Execution unit, are the two different functional units in 8086.
What are the various segment registers in 8086?
Code, Data, Stack, Extra Segment registers in 8086.
What does EU do?
Execution Unit receives program instruction codes and data from BIU, executes these instructions and store the result in general registers.
Which Stack is used in 8086? k is used in 8086?
FIFO (First In First Out) stack is used in 8086.In this type of Stack the first stored information is retrieved first.
What are the flags in 8086?
In 8086 Carry flag, Parity flag, Auxiliary carry flag, Zero flag, Overflow flag, Trace flag, Interrupt flag, Direction flag, and Sign flag.
What is SIM and RIM instructions?
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.
What is the difference between 8086 and 8088?
The BIU in 8088 is 8-bit data bus & 16- bit in 8086.Instruction queue is 4 byte long in 8088and 6 byte in 8086.
Give example for Non-Maskable interrupts?
Trap is known as Non-Maskable interrupts, which is used in emergency condition.
Give examples for Micro controller?
Z80, Intel MSC51 &96, Motorola are the best examples of Microcontroller.
What is clock frequency for 8085?
3 MHz is the maximum clock frequency for 8085.
Give an example of one address microprocessor?
8085 is a one address microprocessor.
Give examples for 8 / 16 / 32 bit Microprocessor?
8-bit Processor - 8085 / Z80 / 6800; 16-bit Processor - 8086 / 68000 / Z8000; 32-bit Processor - 80386 / 80486
What is meant by a bus?
A bus is a group of conducting lines that carriers data, address, & control signals.
What are the various registers in 8085?
Accumulator register, Temporary register, Instruction register, Stack Pointer, Program Counter are the various registers in 8085
Why crystal is a preferred clock source?
Because of high stability, large Q (Quality Factor) & the frequency that doesn’t drift with aging. Crystal is used as a clock source most of the times.
In 8085 which is called as High order / Low order Register?
Flag is called as Low order register & Accumulator is called as High order Register.
Name 5 different addressing modes?
Immediate, Direct, Register, Register indirect, Implied addressing modes
In what way interrupts are classified in 8085?
In 8085 the interrupts are classified as Hardware and Software interrupts.
What is the difference between primary & secondary storage device?
In primary storage device the storage capacity is limited. It has a volatile memory. In secondary storage device the storage capacity is larger. It is a nonvolatile memory. Primary devices are: RAM / ROM. Secondary devices are: Floppy disc / Hard disk.
Which Stack is used in 8085?
LIFO (Last In First Out) stack is used in 8085.In this type of Stack the last stored information can be retrieved first.
What is Program counter?
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.
What is the RST for the TRAP?
RST 4.5 is called as TRAP.
What are level-triggering interrupt?
RST 6.5 & RST 5.5 are level-triggering interrupts.
Which interrupt is not level-sensitive in 8085?
RST 7.5 is a raising edge-triggering interrupt.
What are Software interrupts?
RST0, RST1, RST2, RST3, RST4, RST5, RST6, RST7.
What are the various flags used in 8085?
Sign flag, Zero flag, Auxiliary flag, Parity flag, Carry flag.
In 8085 name the 16 bit registers?
Stack pointer and Program counter all have 16 bits.
What is Stack Pointer?
Stack pointer is a special purpose 16-bit register in the Microprocessor, which holds the address of the top of the stack.
What happens when HLT instruction is executed in processor?
The Micro Processor enters into Halt-State and the buses are tri-stated.
What does Quality factor mean?
The Quality factor is also defined, as Q. So it is a number, which reflects the lossness of a circuit. Higher the Q, the lower are the losses.
How many interrupts are there in 8085?
There are 12 interrupts in 8085.
What is Tri-state logic?
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.
Which interrupt has the highest priority?
TRAP has the highest priority
What are Hardware interrupts?
TRAP, RST7.5, RST6.5, RST5.5, INTR
Can an RC circuit be used as clock source for 8085?
Yes, it can be used, if an accurate clock frequency is not required. Also, the component cost is low compared to LC or Crystal




































What is a Microprocessor?
Microprocessor is a program-controlled device, which fetches the instructions from memory, decodes and executes the instructions. Most Micro Processor are single- chip devices.

What is the difference between microprocessor and microcontroller?
The major difference is microprocessor doesn’t have inbuilt memory but micro-controller has inbuilt memory .In Microprocessor more op-codes, few bit handling instructions. But in Microcontroller: fewer op-codes, more bit handling Instructions. Micro-controller can be defined as a device that includes micro processor, memory, & input / output signal lines on a single chip.

Give examples for 8 / 16 / 32 bit Microprocessor?
8-bit Processor - 8085 / Z80 / 6800;
16-bit Processor - 8086 / 68000 / Z8000;
32-bit Processor - 80386 / 80486.

Why 8085 processor is called an 8 bit processor?
Because 8085 processor has 8 bit ALU (Arithmetic Logic Review).

Expand HCMOS?
High-density n- type Complimentary Metal Oxide Silicon field effect transistor.

What does microprocessor speed depend on?
The processing speed depends on DATA BUS WIDTH.

What is the Maximum clock frequency in 8086?
5 Mhz is the Maximum clock frequency in 8086

Is the address bus unidirectional? Is the data bus is Bi-directional?
The address bus is unidirectional because the address information is always given by the Micro Processor to address a memory location of an input / output devices.
The data bus is Bi-directional because the same bus is used for transfer of data between Micro Processor and memory or input / output devices in both the direction.

What is the disadvantage of microprocessor?
It has limitations on the size of data. Most Microprocessor does not support floating-point operations.

What is the difference between primary & secondary storage device?
In primary storage device the storage capacity is limited. It has a volatile memory. In secondary storage device the storage capacity is larger. It is a nonvolatile memory. Primary devices are: RAM / ROM.
Secondary devices are: Floppy disc / Hard disk.

Difference between SRAM and DRAM?
Static RAM: No refreshing, 6 to 8 MOS transistors are required to form one memory cell, Information stored as voltage level in a flip flop.
Dynamic RAM: Refreshed periodically, 3 to 4 transistors are required to form one memory cell, Information is stored as a charge in the gate to substrate capacitance.

What is an interrupt?
Interrupt is a signal send by external device to the processor so as to request the processor to perform a particular work.

What are the different types of interrupts?
Maskable and Non-maskable interrupts.

What is cache memory?
Cache memory is a small high-speed memory. It is used for temporary storage of data & information between the main memory and the CPU (center processing unit). The cache memory is only in RAM.

Expand DMA?
Direct Memory Access

Differentiate between RAM and ROM?
RAM: Random Access Memory. Read / Write memory, High Speed, Volatile Memory. ROM: Read only memory, Low Speed, Non Volatile Memory

What is NV-RAM?
Nonvolatile Read Access Memory, also called Flash memory.

What is a flag?
Flag is a flip-flop used to store the information about the status of a processor and the status of the instruction executed most recently

What are the flags in 8086?
In 8086 Carry flag, Parity flag, Auxiliary carry flag, Zero flag, Overflow flag, Trace flag, Interrupt flag, Direction flag, and Sign flag.

What is meant by Maskable interrupt?
An interrupt that can be turned off by the programmer is known as Maskable interrupt.

What is Non-Maskable interrupt?
An interrupt which can be never be turned off (ie.disabled) is known as Non-Maskable interrupt.

Which interrupts are generally used for critical events?
Non-Maskable interrupts are used in critical events. Such as Power failure, Emergency, Shut off etc.

Give examples for Maskable interrupts?
RST 7.5, RST6.5, RST5.5 are Maskable interrupts

Give example for Non-Maskable interrupts?
Trap is known as Non-Maskable interrupts, which is used in emergency condition.

What are the various segment registers in 8086?
Code, Data, Stack, Extra Segment registers in 8086.

Which Stack is used in 8086?
FIFO (First In First Out) stack is used in 8086.In this type of Stack the first stored information is retrieved first.

What is SIM and RIM instructions?
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.

What is Tri-state logic?
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.

Give an example of one address microprocessor?
8085 is a one address microprocessor.

In what way interrupts are classified in 8085?
In 8085 the interrupts are classified as Hardware and Software interrupts.

What are Hardware interrupts?
TRAP, RST7.5, RST6.5, RST5.5, INTR.

What are Software interrupts?
RST0, RST1, RST2, RST3, RST4, RST5, RST6, RST7.

Which interrupt has the highest priority?
TRAP has the highest priority.

Name 5 different addressing modes?
Immediate, Direct, Register, Register indirect, Implied addressing modes.

How many interrupts are there in 8085?
There are 12 interrupts in 8085.

What is the RST
 for the TRAP?
RST 4.5 is called as TRAP.

In 8085 which is called as High order / Low order Register?
Flag is called as Low order register & Accumulator is called as High order Register.

















1. What is a Microprocessor?
Answer

A microprocessor is a programmable digital electronic component that incorporates the functions of a central processing unit (CPU) on a single semi conducting integrated circuit (IC). Instructions are fetched from memory, the they are decoded, and finally executed.

2. Why does microprocessor contain ROM chips?
Answer

Microprocessor uses ROM chips to store instructions, which are used to execute data.

3. What is the difference between a microprocessor and a microcontroller?
Answer

Microprocessor contains more op-codes, and few bit handling instructions. Where as a microcontroller contains few op-codes and more bit handling instructions. It can be called as a computer on a chip. In addition to all arithmetic and logic elements of a general purpose microprocessor, the microcontroller usually also integrates additional elements such as read-only and read-write memory, and input/output interfaces.

4. Give examples for 8, 16, and 32 bit microprocessors.
Answer

8-bit processors: MC6800, Intel 8008, Intel 8080, Z80.
16-bit processors: MC68000, Intel 8086.
32-bit processors: Intel 80386, Intel 80486, Z8000.

5. Give an example of a microprocessor, whose structure is pipelined.
Answer

All x86 processors have pipelined structure. Intel 8086, Intel 80386, etc.

6. What is flag? Give some examples of a flag.
Answer

7. What are most common registers present in a microprocessor?
Answer

Accumulator registers, Data registers, Temporary registers, Instruction registers, Stack Pointer, Program Counter and Condition Code Register.

8. Why is address bus unidirectional?
Answer

The address bus is unidirectional because the address is always given by the microprocessor, to address a memory location of an I/O device. Only microprocessor can write a value onto address bus, I/O devices can only read address bus.

9. Why is data bus bidirectional?
Answer

The data bus is bidirectional because the it is used by microprocessor, memory units, and I/O devices for both to transfer and receive data.

10. Expand RAM, ROM, PROM, EPROM, EEPROM.
Answer

RAM: Random Access Memory.
ROM: Read Only Memory.
PROM: Programmable Read Only Memory.
EPROM: Erasable Programmable Read Only Memory..
EEPROM: Electrically Erasable Programmable Read Only Memory.


















































8085 questions and answers
1. What are the various registers in 8085?
- Accumulator register, Temporary register, Instruction register, Stack Pointer, Program Counter are the various registers in 8085 .

2. In 8085 name the 16 bit registers?
- Stack pointer and Program counter all have 16 bits.

3. What are the various flags used in 8085?
- Sign flag, Zero flag, Auxillary flag, Parity flag, Carry flag.

4. What is Stack Pointer?
- Stack pointer is a special purpose 16-bit register in the Microprocessor, which holds the address of the top of the stack.

5. What is Program counter?
- 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.

6. Which Stack is used in 8085?
- LIFO (Last In First Out) stack is used in 8085.In this type of Stack the last stored information can be retrieved first.

7. What happens when HLT instruction is executed in processor?
- The Micro Processor enters into Halt-State and the buses are tri-stated.

8. What is meant by a bus?
- A bus is a group of conducting lines that carriers data, address, & control signals.

9. What is Tri-state logic?
- 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.

10. Give an example of one address microprocessor?
- 8085 is a one address microprocessor.

11. In what way interrupts are classified in 8085?
- In 8085 the interrupts are classified as Hardware and Software interrupts.

12. What are Hardware interrupts?
- TRAP, RST7.5, RST6.5, RST5.5, INTR.

13. What are Software interrupts?
- RST0, RST1, RST2, RST3, RST4, RST5, RST6, RST7.

14. Which interrupt has the highest priority?
- TRAP has the highest priority.

15. Name 5 different addressing modes?
- Immediate, Direct, Register, Register indirect, Implied addressing modes.

16. How many interrupts are there in 8085?
- There are 12 interrupts in 8085.

17. What is clock frequency for 8085?
- 3 MHz is the maximum clock frequency for 8085.

18. What is the RST for the TRAP?
- RST 4.5 is called as TRAP.

19. In 8085 which is called as High order / Low order Register? - Flag is called as Low order register & Accumulator is called as High order Register.

20. What are input & output devices?
- Keyboards, Floppy disk are the examples of input devices. Printer, LED / LCD display, CRT Monitor are the examples of output devices.

21. Can an RC circuit be used as clock source for 8085?
- Yes, it can be used, if an accurate clock frequency is not required. Also, the component cost is low compared to LC or Crystal.

22. Why crystal is a preferred clock source?
- Because of high stability, large Q (Quality Factor) & the frequency that doesn’t drift with aging. Crystal is used as a clock source most of the times.

23. Which interrupt is not level-sensitive in 8085?
- RST 7.5 is a raising edge-triggering interrupt.

24. What does Quality factor mean?
- The Quality factor is also defined, as Q. So it is a number, which reflects the lossness of a circuit. Higher the Q, the lower are the losses.

25. What are level-triggering interrupt?
- RST 6.5 & RST 5.5 are level-triggering interrupts

·  26.Which Stack is used in 8085?LIFO (Last In First Out) stack is used in 8085.In this type of Stack the last stored information can be...
· 
·  27.What are the various registers in 8085?Accumulator register, Temporary register, Instruction register, Stack Pointer, Program Counter are the various registers in 8085...
· 
·  28.What are the various registers in 8085?Accumulator register, Temporary register, Instruction register, Stack Pointer, Program Counter are the various registers in 8085...
· 
·  29.In 8085 name the 16 bit registers?Stack pointer and Program counter all have 16 bits....
· 
·  30.What is Stack Pointer?Stack pointer is a special purpose 16-bit register in the Microprocessor, which holds the address of the top of the...
· 
·  31.Which StacWhich Stack is used in 8086? k is used in 8086?FIFO (First In First Out) stack is used in 8086.In this type of Stack the first stored information is retrieved...
· 
·  32.How can I handle a destructor that fails?Write a message to a log-file. But do not throw an exception. The C++ rule is that you must never throw...
· 
·  33.In what way interrupts are classified in 8085?In 8085 the interrupts are classified as Hardware and Software interrupts....
· 
·  34.What method is used to place a value onto the top of a stack?push() method, Push is the direction that data is being added to the stack. push() member method places a value...
· 
·  35.What is clock frequency for 8085?3 MHz is the maximum clock frequency for 8085....
36.What is clock frequency for 8085?
3 MHz is the maximum clock frequency for 8085.
37.Give an example of one address microprocessor?
8085 is a one address microprocessor.
38.Give examples for 8 / 16 / 32 bit Microprocessor?
8-bit Processor - 8085 / Z80 / 6800; 16-bit Processor - 8086 / 68000 / Z8000; 32-bit processor - 80386 / 80486
39.What is meant by a bus?
A bus is a group of conducting lines that carriers data, address, & control signals.
40.What are the various registers in 8085?
Accumulator register, Temporary register, Instruction register, Stack Pointer, Program Counter are the various registers in 8085
41.Why crystal is a preferred clock source?
Because of high stability, large Q (Quality Factor) & the frequency that doesn?t drift with aging. Crystal is used as a clock source most of the times.
42.In 8085 which is called as High order / Low order Register?
Flag is called as Low order register & Accumulator is called as High order Register.
43.Name 5 different addressing modes?
Immediate, Direct, Register, Register indirect, Implied addressing modes
44.In what way interrupts are classified in 8085?
In 8085 the interrupts are classified as Hardware and Software interrupts.
45.What is the difference between primary & secondary storage device?
In primary storage device the storage capacity is limited. It has a volatile memory. In secondary storage device the storage capacity is larger. It is a nonvolatile memory. Primary devices are: RAM / ROM. Secondary devices are: Floppy disc / Hard disk.
46.Which Stack is used in 8085?
LIFO (Last In First Out) stack is used in 8085.In this type of Stack the last stored information can be retrieved first.
47.What is Program counter?
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.
48.What is the RST for the TRAP?
RST 4.5 is called as TRAP.
49.What are level-triggering interrupt?
RST 6.5 & RST 5.5 are level-triggering interrupts.
50.Which interrupt is not level-sensitive in 8085?
RST 7.5 is a raising edge-triggering interrupt.
51.What are Software interrupts?
RST0, RST1, RST2, RST3, RST4, RST5, RST6, RST7.
52.What are the various flags used in 8085?
Sign flag, Zero flag, Auxiliary flag, Parity flag, Carry flag.
53.In 8085 name the 16 bit registers?
Stack pointer and Program counter all have 16 bits.
54.What is Stack Pointer?
Stack pointer is a special purpose 16-bit register in the Microprocessor, which holds the address of the top of the stack.
55.What happens when HLT instruction is executed in processor?
The Micro Processor enters into Halt-State and the buses are tri-stated.
56.What does Quality factor mean?
The Quality factor is also defined, as Q. So it is a number, which reflects the lossness of a circuit. Higher the Q, the lower are the losses.
57.How many interrupts are there in 8085?
There are 12 interrupts in 8085.
58.What is Tri-state logic?
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.
59.Which interrupt has the highest priority?
TRAP has the highest priority
60.What are Hardware interrupts?
TRAP, RST7.5, RST6.5, RST5.5, INTR
61.Can an RC circuit be used as clock source for 8085?
Yes, it can be used, if an accurate clock frequency is not required. Also, the component cost is low compared to LC or Crystal

8086 questions and answers
  1. What is a Microprocessor? - Microprocessor is a program-controlled device, which fetches the instructions from memory, decodes and executes the instructions. Most Micro Processor are single- chip devices.
  2. Give examples for 8 / 16 / 32 bit Microprocessor? - 8-bit Processor - 8085 / Z80 / 6800; 16-bit Processor - 8086 / 68000 / Z8000; 32-bit Processor - 80386 / 80486.
  3. Why 8085 processor is called an 8 bit processor? - Because 8085 processor has 8 bit ALU (Arithmetic Logic Review). Similarly 8086 processor has 16 bit ALU.
  4. What is 1st / 2nd / 3rd / 4th generation processor? - The processor made of PMOS / NMOS / HMOS / HCMOS technology is called 1st / 2nd / 3rd / 4th generation processor, and it is made up of 4 / 8 / 16 / 32 bits.
  5. Define HCMOS? - High-density n- type Complimentary Metal Oxide Silicon field effect transistor.
  6. What does microprocessor speed depend on? - The processing speed depends on DATA BUS WIDTH.
  7. Is the address bus unidirectional? - The address bus is unidirectional because the address information is always given by the Micro Processor to address a memory location of an input / output devices.
  8. Is the data bus is Bi-directional? - The data bus is Bi-directional because the same bus is used for transfer of data between Micro Processor and memory or input / output devices in both the direction.
  9. What is the disadvantage of microprocessor? - It has limitations on the size of data. Most Microprocessor does not support floating-point operations.
  10. What is the difference between microprocessor and microcontroller? - In Microprocessor more op-codes, few bit handling instructions. But in Microcontroller: fewer op-codes, more bit handling Instructions, and also it is defined as a device that includes micro processor, memory, & input / output signal lines on a single chip.
  11. What is meant by LATCH? - Latch is a D- type flip-flop used as a temporary storage device controlled by a timing signal, which can store 0 or 1. The primary function of a Latch is data storage. It is used in output devices such as LED, to hold the data for display.
  12. Why does microprocessor contain ROM chips? - Microprocessor contain ROM chip because it contain instructions to execute data.
  13. What is the difference between primary & secondary storage device? - In primary storage device the storage capacity is limited. It has a volatile memory. In secondary storage device the storage capacity is larger. It is a nonvolatile memory. Primary devices are: RAM / ROM. Secondary devices are: Floppy disc / Hard disk.
  14. Difference between static and dynamic RAM? - Static RAM: No refreshing, 6 to 8 MOS transistors are required to form one memory cell, Information stored as voltage level in a flip flop. Dynamic RAM: Refreshed periodically, 3 to 4 transistors are required to form one memory cell, Information is stored as a charge in the gate to substrate capacitance.
  15. What is interrupt? - Interrupt is a signal send by external device to the processor so as to request the processor to perform a particular work.
  16. What is cache memory? - Cache memory is a small high-speed memory. It is used for temporary storage of data & information between the main memory and the CPU (center processing unit). The cache memory is only in RAM.
  17. What is called .Scratch pad of computer.? - Cache Memory is scratch pad of computer.
  18. Which transistor is used in each cell of EPROM? - Floating .gate Avalanche Injection MOS (FAMOS) transistor is used in each cell of EPROM.
  19. Differentiate between RAM and ROM? - RAM: Read / Write memory, High Speed, Volatile Memory. ROM: Read only memory, Low Speed, Non Voliate Memory.
  20. What is a compiler? - Compiler is used to translate the high-level language program into machine code at a time. It doesn.t require special instruction to store in a memory, it stores automatically. The Execution time is less compared to Interpreter.
  21. Which processor structure is pipelined? - All x86 processors have pipelined structure.
  22. What is flag? - Flag is a flip-flop used to store the information about the status of a processor and the status of the instruction executed most recently
  23. What is stack? - Stack is a portion of RAM used for saving the content of Program Counter and general purpose registers.
  24. Can ROM be used as stack? - ROM cannot be used as stack because it is not possible to write to ROM.
  25. What is NV-RAM? - Nonvolatile Read Write Memory, also called Flash memory. It is also know as shadow RAM.








































Interview Questions on Microprocessor:-
1) What type of architecture used in 8085 microprocessor?Interview Questions on Microprocessor 8085
Ans. 8085 has Von Neumann architecture. It is named after the mathematician John   Von Neumann. It is based on the concept of stored program control. In this architecture both the data and the program is stored in the same memory.
2) What is the function of accumulator?Interview Questions on Microprocessor 8085
Ans. Accumulator is an 8 bit register which stores data and performs arithmetic and logical operations. The result of the operation is stored in the accumulator. It is designated by the letter ‘A’.
3) What are the different types of flags in 8085 microprocessor?Interview Questions on Microprocessor 8085
Ans. There are 5 different flags in 8085 microprocessor. Though the flag register is of 8 bit but 3 bits are not in use. Only 5 bits are used for the different flags. They are:-
a) Sign flag(s)- This is designated by the letter ‘S’. If sign bit is 1 then the sign flag is set to 1 and if the sign bit is zero then sign flag is reset to zero.
b) Zero flag(z)- This is designated by the letter ‘z’. If the result of any arithmetic or logical operation is zero i.e. all the bits are zero then zero flag is set to 1 else it is set to zero.
c) Auxiliary carry- (AC) This flag is set to 1 only when any intermediate carry is produced. Else it is reset to 0.
d) Parity flag (P) – when the result of any operation has odd number of ones then parity flag is set to 1 else if it has even number of ones then it is reset to 0.
e) Carry flag(C) – this flag is set to 1 only when a carry is produced in the result i.e. the carry bit is 1 else if the carry bit is zero then the flag is reset to zero.
4)  What are the types of general purpose registers in 8085? 
Ans. There are 6 general purpose registers in 8085 microprocessor. They are designated by the letters – B, C, D, E, H, and L. These are 8 bit registers and are used to store data temporarily during the execution of any program. These registers can also be used to store 16 bit data by using them in pairs i.e. BC, DE and HL. These pairs cannot be changed as B cannot pair with any other register other than C.
5)  What is the length of stack pointer in 8085 microprocessor? And what is its use? Interview Sample paper question answer on 8085 Microprocessor.
Ans. stack pointer is of 16 bits length and is used to point to the value at top of the stack for the currently executed instruction.
6)  What is the memory size of 8085 microprocessor? Placement Interview Sample paper question answer on 8085 Microprocessor
Ans. 8085 has 8 data lines and 16 address lines. The memory size of any microprocessor depends on the number of address lines. The general formula is 2^n, where n= number of address lines. For 8085 there are  2^16= 64 Kbytes memory size.
7)  How many bits is 8085 microprocessor? Sample Paper Interview question answer
Ans. Microprocessor is named on the basis of number of data lines in it. 8085 is a bit microprocessor as it has 8 bit data lines.
8)  What are the various interrupts in 8085 microprocessor? Which is the highest priority interrupt? Important questions on Microprocessor 8085
There are 6 types of interrupts in 8085. They are
a) TRAP
b) RST 7.5
c) RST 6.5
d) RST 5.5
e) INTR
f) Interrupt acknowledgment (INTA(bar)).
TRAP has the highest priority among all the interrupts.
9)  Which type of cycle is used for fetch and execute instruction? Sample Paper Interview question answer
 Ans. Instruction cycle is used for the fetch and execute instruction.
In this cycle the instruction is fetched, decoded and executed to produce the required output.
10)  How many address lines are there in 8085 microprocessor? Sample Paper Interview question answer
Ans. There are 16 address lines in 8085. They are multiplexed address and data lines. Address bus of 8085 is of 16 bits. During the first machine cycle these address lines are used as data lines and in the next machine cycle all the 16 lines act as address lines.
The multiplexed 8 address and data lines refer to lower order address bit and the rest 8 for higher order address bits.
11) What is a Microprocessor?
Ans:- Microprocessor is a program-controlled device, that fetches the instructions from memory, decode it & executes the instructions. Generally Microprocessor are single- chip devices.
12) Why crystal is  being preferred as a clock source?
Ans:- Reasons-high stability, large Q (Quality Factor) & the frequency that doesn’t drift with aging. so crystal is used as a clock source most of the times.
13) Name High order / Low order Register in 8085 microprocessor?
Ans:-Flag is called Low order register & Accumulator is called High order Register in 8085 microprocessor.
14) Describe Tri-state logic?
Ans:- Three Logic Levels are used and they are known as High, Low, High impedance state. The high and low are said to be normal logic levels where as high impedance state is electrical open circuit conditions. Tri-state logic has a enable line as third line
15) What will happen if HLT instruction is executed in processor?
Ans:- The Micro Processor will enter into Halt-State and the buses will be tri-stated.
16) Which Stack is used in 8085?
Ans:- LIFO (Last In First Out) stack is used in 8085.In this type of Stack the information which is stored last will be taken out or retrieved first.
17)  Describe briefly Program counter?
Ans:- Program counter does either of the two things that is it 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 was not completely fetched. In both the cases it is incremented automatically one by one as the instruction bytes will be fetched. Program register also keeps the next instruction address.
18) Name the 1st / 2nd / 3rd / 4th generation processor?
Ans:-The processor are made of PMOS / NMOS / HMOS / HCMOS technology  which is called 1st / 2nd / 3rd / 4th generation processor, and  that is made up of 4 / 8 / 16 / 32 bits respectively.
19)  Name the processor lines of two major manufacturers?
Ans:-  The Processor lines names of two major manufacturers are as follows:- At High-end: Intel – Pentium (II, III, IV), AMD – Athlon. At Low-end: Intel – Celeron, AMD – Duron. 64-bit: Intel – Itanium 2, AMD – Opteron
20)  Mention the speed and device maximum specs for Firewire?
Ans:-IEEE 1394 (Firewire) with speeds up to 400 Mbps can support the maximum of 63 connected devices
21) Where’s MBR located on the disk?
Ans:- The place where MBR is situated is in sector 0, track 0, head 0, cylinder 0 of the primary active partition.
22) Where does CPU Enhanced mode originate from?
Ans:- Intel’s 80386 was the first 32-bit processor, and so the company had to backward-support the 8086. All the modern Intel-based processors run in the enhanced mode which are capable to switch in between real mode and protected mode, which is the current mode of operation.
23) What are the types of buses?
Ans:- Three types of buses are there:-
Address bus: It carries the Address to the memory to fetch either instruction..
Data bus : It carries data from the memory.
Control bus : It carries the control signals like RD/WR, Select etc.
24) What does EU do?
Ans:- Execution Unit receives both program instruction codes & data from Bus Interface Unit and then executes these instructions and the result is being stored in registers.
25) Mention RST for the TRAP?
Ans:- RST 4.5
26) Can an RC circuit be used as clock source for 8085?
Ans:-Yes,RC circuit can be used as clock source if in case an accurate clock frequency is not required. The cost of RC is low as compared to LC.
Microprocessor interview questions on 8086
27) What are the types of flags in 8086?
Ans:- In 8086 there are 9 types of flags which are as follows Carry flag, Parity flag, Auxiliary carry flag, Zero flag, Overflow flag, Trace flag, Interrupt flag, Direction flag, and Sign flag.
28) What are the various interrupts in 8086?
Ans:- Two types of interrupts:-Maskable interrupts, Non-Maskable interrupts.
29) What is meant by Maskable interrupts?
Ans:- An interrupt that can be turned off by the programmer is known as Maskable interrupts are those interrupts which can be turned off by the programmer or can be ignored by the programmer.
30) What is Non-Maskable interrupts?
Ans:- A processor interrupt which can be never be turned off (i.e.disabled) or cannot be ignored by the programmer is known as Non-Maskable interrupt.
31) Which interrupts are generally used for critical events?
Ans:- Non-Maskable interrupts are generally used in critical events. For example- Power failure, Emergency, Shut off etc.
32) Give some examples for Maskable interrupts?
Ans:- Some examples for maskable interrupts are as follows:- RST 7.5, RST6.5, RST5.5
33) Give  some example for Non-Maskable interrupts?
Ans:- Trap is called as Non-Maskable interrupts, which is used during emergency condition.
34) What is the Maximum clock frequency in 8086?
Ans:- 5 Mhz
35) Name the various segment registers in 8086?
Ans:- The various segment registers in 8085 are- Code, Data, Stack, Extra Segment registers.
36) Which Stack is used in 8086?
Ans:- FIFO (First In First Out) stack is used in 8086.In this type of Stack the information which is stored first is taken out or  retrieved first.
37) What is SIM and RIM instructions?
Ans:- SIM is Set Interrupt Mask. which is used to mask the hardware interrupts. RIM is Read Interrupt Mask which is used to check whether the interrupt is masked or not.
38) Which is the tool which is used to connect the user and the computer?
Ans:- Interpreter
39) What is the position of the Stack Pointer after the PUSH instruction?
Ans:- The address line is 02 less than the earlier value.
40) What is the position of the Stack Pointer after the POP instruction?
Ans:- The address line is 02 greater than the earlier value.
These are some of the interview questions and answers on Microprocessor. If you want to add some more, please mention in the comment section of the post.


 
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