8085 Microprocessor – very short answer type Question set (with answers)

Very short answer type questions with answers given in brackets.

1. In 8085, the DAA instruction is used for _ (Decimal Adjust Accumulator)
2. Addressing mode used in instruction PUSH B is __( Register Addressing mode)
3. What is the call location for TRAP interrupt? ( 0024h )
4. How many address lines are required for 32kB memory chip? ( 15 )
5. What are the software interrupt in 8085 microprocessor? (RST 0-7)
6. When the IN and OUT instructions are executed, the address of I/O device is placed in low order address bus. At this time what will be the content of high order address bus? (Same content as of low order address bus.)
7. Which port of 8255 PPI can be used in BSR mode? (Port C only )
8. _ Machine cycles are required for the execution of “INRM” instruction. (3 machine cycle)
9. In which mode of operation 8255 PPI supports bi-directional data transfer? ( Mode-2 )
10. How many machine cycles are required for the execution of “CALL” instruction? ( 5 )
11. The CWR address of 8255 connected to 8085 is FB h, what will be the address for Port A? ( F8h)
12. Mode 2 operation of 8255 is known as __. ( Bi-directional data transfer mode )
13. Single instruction which is used to clear the lower four bits of the accumulator in 8085 is_________. ( ANI F0 H)
14. Which instruction is needed to enable the interrupt TRAP in 8085? (EI )
15. Stack pointer register is used to hold _. ( stack top address)
16. To initiate DMA data transfer the signal to be sent to the 8085 CPU is _. ( HOLD )
17. CMA instruction is an example of 8085 that uses _ addressing mode. (Implicit)
18. Between DCR and DCX instructions, the status flags are affected by _. (only DCR)
19. The clock frequency of 8085 microprocessor is 5MHz. If the time required for executing an instruction is 1.4 µs, then the number of T-states needed for executing the instruction is_____.
    (7 T-states)
20. The number of machine cycles required to execute the instruction LDA 3000h in 8085 is______.
    (4 machine cycles)
21. XCHG instruction of 8085 exchanges the content of __. (DE register pair and HL register pair)
22. Which register is used in 8085 to keep the address of next instruction to be fetched? (Program counter)
23. Which instruction is used in 8085 that doubles the value in accumulator? (ADD A )
24. The 8085 microprocessor has ______bit data bus and _____bit address bus. (8, 16)
25. How many T-states are required to execute DAD B instruction? (10 )
26. SIM instruction is used to enable _ ( RST 7.5, RST 6.5, RST5.5)