Programming the 8085.

Programming the 8085.
  1. Sketch the programming model and explain in detail.
  2. What are the various addressing modes available in 8085? Explain with examples.
  3. Explain the instruction format of 8085 microprocessor with an example.
  4. How do you classify the instructions of 8085, based on a) Number of bytes b) Addressing modes? Explain with examples.
  5. Give two examples for each of the following types of instructions and indicate what each of these instructions do:
    1. Instructions with implied addressing.
    2. ALU type of instructions.
    3. Instructions addressing memory indirectly through any register pair.
    4. Conditional branch instructions.
    5. Interrupt related instructions.
  1. Explain fully the action of the following 8085 instructions: ADC M, STAX D, RLC, LHLD 9898, and TRAP.
  2. Explain the following instructions and indicate the flags affected: DAA, DAD D, XCHG, HALT & MOV M, A.
  3. Define Instruction cycle, Machine cycle and T-States with examples.
  4. Explain the following instructions indicating their addressing modes, flags affected, number and names of machine cycles on the execution of each: XRA A, SUB M, & DCXSP.
  5. Draw opcodes fetch machine cycle, memory write machine cycle and I/O read machine cycle and explain.
  6. Explain the various steps involved while executing CALL instruction with an example.
  7. Explain DAA instruction with example.
  8. Explain the functions and timing associated with STA and RST instructions.
  9. Explain the working of CALL address and RET instructions, in terms of machine cycles.
  10. Write an ALP for 8085 to multiply two 8-bit numbers. Explain your program with only comments.
  11. Write a program in 8085 to convert the binary number stored in location XX20h to BCD. Store the possible three BCD digits in unpacked manner from location XX50h.
  12. What is a stack? On what principle it works? Is it necessary to intialize stack pointer while writing program? Explain with example.
  13. Mention the uses of stack. Sketch the content of SP and stack memory after the execution of each of the following instructions in the given order, if SP = 1000h, BC = 2030h and DE = 4050h initially: PUSH B and PUSH D.
  14. With suitable programming example clearly explain passing the parameter through registers, through memory and through stack.
  15. Explain stack operation in detail.
  16. Sketch and explain briefly the timing diagram of the instruction MVI A, 32h, which is stored from address 3000h.
  17. Draw the timing diagram for the instruction STA 9000h.
  18. Write an 8085 program to simulate a decimal upcounter to count 00 to 99. Use delay of 100 msec in between counts. Assume the operating frequency as 2 MHz.
  19. What is the use of instruction ORA A? What is the status of CY and AC flags after the execution of this instruction?
  20. Write a recursive subroutine named FACT to find factorial of the number in 8085.
  21. Using JMP, can you call a subroutine? Explain with an example and a corresponding ALP.
  22. Write an ALP to count number of 1’s and 0’s present in a hex byte present at 9100h memory location. Store number of 1’s at 9101h and number of 0’s at 9102h.
  23. Write an ALP for 8085 processor to separate ODD and EVEN numbers from an array of 16 numbers stored from F100h. Store the EVEN numbers from F120h and ODD numbers from F150h.
  24. Write an ALP subroutine to produce a delay of 1 second. Consider the 8085 clocked at 5 MHz.
  25. What is a subroutine? How it is useful? Explain the use of stack in CALL and RET instructions.
  26. Explain any five logical instructions with their function, addressing modes and flags affected.
Any of the instructions can be asked for explanation.
One must Cover lab programs also.

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