ðŦ National Institute of Technology Silchar
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| Q.N. | Questions | Marks | CO |
|---|---|---|---|
| 1. (a) | What are the advantages of instruction queue in 8086 as compared to 8085? What is the usage of source index (SI) and destination index (DI) in 8086? | 3 | CO-3 |
| (b) | How are the physical addresses are calculated in 8086? Illustrate through example? | 2 | CO-3 |
| (c) | List down 8 general purpose register, each of which is 16 bits wide in 8086. Which specific register is used for count application? | 3 | CO-3 |
| 2. (a) | Explain DMA Master and Slave mode. | 2 | CO-3 |
| (b) | What is a interrupt in 8085? List all the interrupts. Explain SIM and RIM instructions. | 1+1+3 | CO-3 |
| (c) | Write a program assuming the microprocessor is completing an RST 5.5 interrupt request, check to see if RST 7.5 is pending. If it is pending, enable RST 7.5 without affecting any other interrupts, otherwise, return to the main program. | 5 | CO-2 |
| 3. (a) | Calculate the total delay for the given set of instructions.LXI B,2384H - 10 T-StatesLOOP: DCX B - 6 T-StatesMOV A, C - 4 T-StatesORA B - 4 T-StatesJNZ LOOP - 10/7 T-States | 5 | CO-1 |
| (b) | Calculate the total delay for the given set of instructionsMVI B, 38H - 7 T-StatesLOOP2: MVI C, FFH - 7 T-StatesLOOP 1: DCR C - 4 T-StatesJNZ LOOP 1 - 10/7 T-StatesDCR B - 4 T-StatesJNZ LOOP 2 - 10/7 T-States | 5 | CO-1 |
| 4. | Write a program to count continuously the hexadecimal numbers from FFH to 00H in a system with a 0.5Ξs clock period. Use register C to set up one millisecond (ms) delay between each count and display the numbers at one of the output ports. | 10 | CO-1 |
| 5. | Write a 20ms time delay subroutine using register pair BC Clear the Z flag without affecting any other flag register and return to the main program. | 10 | CO-1 |
| OR | |||
| 6. | A railway crossing signal has two flashing lights run by a microcomputer. One light is connected to data bit Dâ and the second light is connected to data bit Dâ. Write a program to turn each signal light alternatively on and off at an interval of 1 second.Note: Flowchart and description of the instructions in programming questions is a must. | 10 | CO-1 |
