EXERCISE 1: 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 tristated. 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? 1 21. Why crystal is a preferred clock source? Because of high stability. Which interrupt is not level-sensitive in 8085? RST 7. 13. Direct. What are Hardware interrupts? TRAP. CRT Monitor are the examples of output devices. RST7. 20. RST5. How many interrupts are there in 8085? There are 12 interrupts in 8085. What are input & output devices? Keyboards. 19. RST3. 23. RST2. What is clock frequency for 8085? 3 MHz is the maximum clock frequency for 8085. Crystal is used as a clock source most of the times. it can be used. Register. large Q (Quality Factor) & the frequency that doesn’t drift with aging. INTR. What is the RST for the TRAP? RST 4. 22.5 is called as TRAP. Implied addressing modes. What does Quality factor mean? 2 . Register indirect.5 is a raising edge-triggering interrupt. 12. 15. RST6.In 8085 the interrupts are classified as Hardware and Software interrupts. Which interrupt has the highest priority? TRAP has the highest priority. Also.5. RST5. the component cost is low compared to LC or Crystal. RST4.5.5. 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 are Software interrupts? RST0. if an accurate clock frequency is not required. 24. LED / LCD display. 18. RST1. Floppy disk are the examples of input devices. Can an RC circuit be used as clock source for 8085? Yes. 17. Name 5 different addressing modes? Immediate. 14. RST6. Printer. RST7. 16. C 3 . So it is a number. What are level-triggering interrupt? RST 6. as Q.E D.The Quality factor is also defined. Higher the Q.5 & RST 5. write a program that will transfer five byte of memory from location 3000H through 3004H to location 3200H through 3204H LDA STA LDA STA LDA STA LDA STA LDA STA 2.L H. the lower are the losses. 25.D L. MOV MOV MOV MOV MOV MOV B.H C. 3000H 3200H 3001H 3201H 3002H 3202H 3003H 3203H 3004H 3204H Write a program to exchange the contents of HL register pair with DE register pair using MOV instruction. which reflects the lossness of a circuit.5 are level-triggering interrupts.B E. Using LDA and STA instructions. EXERCISE 2: 1. Write a program using the ADI instruction to add the two hexadecimal numbers 3AH and 48H and store the result in memory location 2100H. MVI A.B C E 3000H A.B C E 3001H A. Store the result in register C. MOV ANA ANA STA MOV ORA ORA STA MOV XRA A.3AH ADI 48H STA 2100H 5.B C 4 . Write a program to subtract the number in the D register from the number in the E register.A 6.3. Write a program to swap lower 4 bit nibble with upper 4 bit nibble of 8 bit data at memory location 2100H and place a result to location 2101H. OR and XOR together the contents of register B. 3001H and 3002H. MOV A.E SUB D MOV C. C and E and place the result into memory location 3000H. LDA 2100H RAL RAL RAL RAL STA 2101H 4. Write an assembly language program that AND. the sum may be of 16-bits.H D C. B. MOV SUB MOV MOV SBB MOV A. Write an 8085 assembly language program using minimum number of instructions to add the 16 bit number in BC.A 5 . MVI A.XRA E STA 3002H 7.00H ADD B JNC LOC INR C LOC:MOV L.A MOV H. DAD B DAD D XCHG 10.A A.L E B.00H H B LOC Write an assembly language program to add two 8-bit numbers. Store the 16 bit result in DE.10H H. Place the result in BC register.C 9.NO1 MVI B. DE & HL. Develop a program in assembly that subtracts the number in the DE register pair from the number in the HL register.NO2 MVI C.2500H M. MVI LXI LOC:MVI INX DCR JNZ 8. Write a program that store 00H into memory location 2500H through 2510H. 10H LOC:MOV A. The first number is stored in memory locations 3800H.11. which checks the number in memory location 2800H.3150H LXI D. then put ‘FF’ in memory location 2810H. 3804H & 3805H.FFH LDA 2800H RAR JNC LOC 6 . Write an 8085 assembly language program. If the number is an even number. Write a program to transfer the entire block of data to new memory locations starting at 3250H. Sixteen bytes of data are stored in memory locations at 3150H to 315FH.A LDA 3805H ADC B STA 3812H 13.M STAX D INX H INX D DCR C JNZ LOC 12.3250H MVI C. Write an 8085 assembly language program. LXI H. which adds two threebyte numbers. 3801H & 3802H and the second number is stored in memory location 3803H. MVI B. LHLD 3800H XCHG LHLD 3803H DAD D SHLD 3810H LDA 3802H MOV B. otherwise put ‘00’. Store the answer in memory locations 3810H upwards. Place the count value in B register.55H M LOC1 B H C LOC2 15.00H A.B LOC:STA 3000H 7 . Store the value in memory location 3000H. LXI MVI MVI MVI LOC2:CMP JNZ INR LOC1:INX DCR JNZ H.A LDA 2801H CMP B JM LOC MOV A.00H LOC:MOV A.B STA 2810H 14. Write an 8085 assembly language program to find the smallest value between two number in memory location 2800H and 2801. LDA 2800H MOV B.2800H C.10H B.MVI B. Write a program to count the data byte in memory that equal to 55H starting at memory location 2800H through 280FH.