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...
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·27.What are the various registers in 8085?Accumulator register, Temporary register, Instruction register, Stack Pointer, Program Counter are the various registers in 8085...
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·28.What are the various registers in 8085?Accumulator register, Temporary register, Instruction register, Stack Pointer, Program Counter are the various registers in 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 / 8048639.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 808541.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 modes44.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 priority60.What are Hardware interrupts? TRAP, RST7.5, RST6.5, RST5.5, INTR61.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
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.
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.
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.
Define 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.
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.
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.
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 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.
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.
Why does microprocessor contain ROM chips? - Microprocessor contain ROM chip because it contain instructions to execute data.
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 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.
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.
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.
What is called .Scratch pad of computer.? - Cache Memory is scratch pad of computer.
Which transistor is used in each cell of EPROM? - Floating .gate Avalanche Injection MOS (FAMOS) transistor is used in each cell of EPROM.
Differentiate between RAM and ROM? - RAM: Read / Write memory, High Speed, Volatile Memory. ROM: Read only memory, Low Speed, Non Voliate Memory.
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.
Which processor structure is pipelined? - All x86 processors have pipelined structure.
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
What is stack? - Stack is a portion of RAM used for saving the content of Program Counter and general purpose registers.
Can ROM be used as stack? - ROM cannot be used as stack because it is not possible to write to ROM.
What is NV-RAM? - Nonvolatile Read Write Memory, also called Flash memory. It is also know as shadow RAM.
