Jawaharlal Nehru Technological University Hyderabad
Jawaharlal Nehru Technological University Hyderabad B.Tech III MICROPROCESSORS AND MICROCONTROLLERS Previous Question Paper (March - 2021 - R16)
Answer any five questions. All questions carry equal marks.
Main
Explain about different addressing modes of 8086 microprocessor with suitable examples.
Answer
The 8086 microprocessor provides several addressing modes to specify the operand for an instruction. These modes determine how the effective address (EA) of the operand is calculated.
1. Immediate Addressing Mode: The operand is specified as an 8-bit or 16-bit constant within the instruction itself. Example: MOV AX, 1234H.
2. Register Addressing Mode: The operand is stored in one of the general-purpose registers. Example: MOV AX, BX.
3. Direct Addressing Mode: The 16-bit effective address is provided directly in the instruction. Example: MOV AX, [1234H].
4. Register Indirect Addressing Mode: The effective address is held in a base register (BX) or index register (SI, DI). Example: MOV AX, [BX].
5. Based Addressing Mode: The effective address is calculated by adding a displacement (8-bit or 16-bit) to the contents of a base register (BX or BP). Example: MOV AX, [BX + 05H].
6. Indexed Addressing Mode: The effective address is calculated by adding a displacement to the contents of an index register (SI or DI). Example: MOV AX, [SI + 05H].
7. Based Indexed Addressing Mode: The effective address is the sum of a base register, an index register, and an optional displacement. Example: MOV AX, [BX + SI + 05H].
8. String Addressing Mode: Used for string instructions where the source address is in SI and the destination address is in DI. Example: MOVSB.
9. Relative Addressing Mode: Used in branch instructions where the target address is calculated by adding a signed 8-bit displacement to the Instruction Pointer (IP). Example: JMP label.
Write about the following instruction set in 8086 microprocessor: i) ADD ii) ROL iii) POP iv) CLD v) SCASB
Answer
i) ADD: Adds the source operand to the destination operand and stores the result in the destination. It affects all arithmetic flags (AF, CF, OF, PF, SF, ZF).
ii) ROL: Rotates the bits of the destination operand to the left by the specified count. The most significant bit shifted out is moved to the least significant bit position and also copied to the Carry Flag (CF).
iii) POP: Copies the data from the top of the stack (pointed to by the Stack Pointer, SP) to the specified destination operand and increments the SP by 2.
iv) CLD: Clears the Direction Flag (DF) to 0. This causes string instructions to process memory in the auto-increment mode (from low address to high address).
v) SCASB: Scans a byte string by subtracting the value in the AL register from the byte at the memory location pointed to by DI. It updates the flags based on the result but does not store the result; it also automatically increments or decrements DI based on the state of the Direction Flag.
Explain the flag register of 8086 microprocessor.
Answer
Sign in to view the complete answer paper.
Draw and explain each block of 8051 microcontroller architecture.
Answer
Sign in to view the complete answer paper.
Describe the program status word of 8051 microcontroller.
Answer
Sign in to view the complete answer paper.
Explain the instruction set of 8051 microcontroller: i) MOVX ii) ANL iii) MUL AB iv) RRC A v) XCH
Answer
Sign in to view the complete answer paper.
Explain about the I2C onboard communication interface.
Answer
Sign in to view the complete answer paper.
Write short notes on keyboards with neat sketches.
Answer
Sign in to view the complete answer paper.
With a neat interface diagram, explain how RAM and ROM are interfaced to 8051 μc.
Answer
Sign in to view the complete answer paper.
Describe about the load store instructions in ARM processor.
Answer
Sign in to view the complete answer paper.
Mention about the software interrupt instructions, in ARM processor.
Answer
Sign in to view the complete answer paper.
What is meant by OMAP? What are the key features of OMAP processor? Explain.
Answer
Sign in to view the complete answer paper.