RABIA ATTACH

  What is DMA and Why it is used? Direct memory access (DMA) is a mode of data transfer between the memory and I/O devices. This happens without the involvement of the processor. We have two other methods of data transfer, programmed I/O and Interrupt driven I/O. Let’s revise each and get acknowledge with their drawbacks. In programmed I/O, the processor keeps on scanning whether any device is ready for data transfer. If an I/O device is ready, the processor fully dedicates itself in transferring the data between I/O and memory. It transfers data at a high rate, but it can’t get involved in any other activity during data transfer. This is the major drawback of programmed I/O. In Interrupt driven I/O, whenever the device is ready for data transfer, then it raises an interrupt to processor. Processor completes executing its ongoing instruction and saves its current state. It then switches to data transfer which causes a delay. Here, the processor doesn’t keep scanning for periphe...

 INTERVIEW QUS ON MP   Our 50+ Microprocessor questions and answers focus on all areas of Microprocessor subject covering the most important topics in the Microprocessor. These topics are chosen from a collection of most authoritative and best reference books on Microprocessor.   1 What does microprocessor speed depend on?   a)Clock b)Data bus width   c)Address bus width d)Control bus width 2 Why 8085 Processor called an 8-bit processor?   a)Because the 8085 processor has 8-Bit ALU. b)Because the 8085 processor has an 8-Bit data bus.   c)Both because the 8085 processor has 8-Bit ALU and because the 8085 processor has an 8-Bit data bus. d)none of these 3 Which one is not a flag bit   a)Parity b)Cary   c)Sign d)Operand 4 What is the maximum number of memory locations supported by 8085?(Probable duplicate)   a)10000 b)32768   c)65536 d)No limit 5 Name of the program responsible to transfer hex input to binary is   a)System Pro...

  THEORY :       In 8085 microprocessor, There is no division operation. To get the result of the division, we should use the repetitive subtraction method. By using this program, we will get the quotient and the reminder. Here we also can be store the carry value. Then store the value of that performed resultant value. ALGORITHM : Step 1: LXI H,2000h; to point source memory location, register pair H-L is initialized.Step 2: MOV A, M; to move the value of memory to the accumulator.Step 3: INX H; to increment the value by 1 for the H-L register pair.Step 4:  MOV B, M; to move the value of memory to the B register.Step 5: MVI C,00h; to load the value 00h in register C.Step 6: CMP B; to compare the value of the accumulator and the B register.Step 7: JC ; to jump on carry in step 11.Step 8: SUB B; to subtract the accumulator and B register value.Step 9: INR C; to increment the value of C register.Step 10: JMP; to jump on step 6 Step 11: INX H; to incre...