Micro processors and micro controllers
JNTUH mid bits
UNIT-1
1.Which of the following register is not present in EU( Execution Unit) of the 8086 microprocessor? [ d]
a. SP b.BP c.SI d.IP
2. Which signal is used to demultiplex the Adress bus of 8086 [ d ]
a. BHE b.LOCK c.READY d.ALE
3. Which of the following signal is used to control the direction of dataflow of bus transcievers [ a ]
a. DT / R b. M / IO c. DEN d.ALE
4. Which of the following signal belongs to maximum mode only [ c ]
a. RD b. TEST c. LOCK d. DEN
5. Which of the following pair of registers is invalid [ a ]
a. CS:SP b. SS: SP c. DS:BX d. ES:DI
6. Which of the following flags is used for single stepping [ c]
a. Direction Flag b. Interrupt Flag c.Trap Flag d. Overflow Flag
7. Which of the following are the three basic sections of a microprocessor unit? [ b]
(A) operand, register, and arithmetic/logic unit (ALU)
(B) control and timing, register, and arithmetic/logic unit (ALU)
(C) control and timing, register, and memory
(D) arithmetic/logic unit (ALU), memory, and input/output
8. Which bus is a bidirectional bus? [ b ]
(A) address bus (B) data bus (C) address bus and data bus (D) none of the above
9. Direction flag is used with [ a]
A) String instructions (B) Stack instructions
(C) Arithmetic instructions (D) Branch instructions
10. What does microprocessor speed depends on? [ c ]
(A) Clock (B) Data bus width (C) Address bus width (D)size of register
11. A register capable of shifting its binary information either to the right or the left is called a[ c] (A)parallel register (B) serial register (C) shift register (D) storage register
12. What is meant by Maskable interrupts? [ b ]
(A) An interrupt which can never be turned off
(B) An interrupt that can be turned off by the programmer
(C) An interrupt which can be turned off automatically
(D) none
13. In a DMA write operation the data is transferred [ a]
(A) from I/O to memory (B) from memory to I/O
(C) from memory to memory (D) from I/O to I/O
Fill in the blanks
1. Flags are divided into control flags & conditional flags
2. Data bus is used for sending and receiving data between CPU and other devices
3. The function of instruction CLC is to reset the carry flag to zero
3. ALE( address latch enable) signal is provided by 8086 to demultiplex the AD0-AD15 into A0-A15 & D0-D15 using external latches.
4. The part of operating system which is loaded in RAM during powerup from harddisk or floppy disk is known as DOS(disk operating system)
6.The cycle required to read from memory is called Machine Cycle.
7.The address available at 8086 pins is called Physical Address
8. The Condition which makes CPU execute next instruction after WAIT instruction is
TEST Becomes Low
UNIT-2
1. Which of the following register holds the address of I/O port of I/O instructions of 8086 [ b ]
a. BX b.DX c.SI d.DI
2. What do the symbols [ ] indicate? [ c]
(A) Direct addressing (B) Register Addressing
C) Indirect addressing (D) None of the above
Fill in the blanks
3. The instruction MOV AX,BX gives that the contents of register BX are copied to AX and stored in it
4. The instruction MOV 1234[BX],3456H is Six (6) bit (opcode) Instruction.
UNIT-3
1. The advantage of memory mapped I/O over I/O mapped I/O is, [ d ]
(A) Faster (B) Many instructions supporting memory mapped I/O
(C) Require a bigger address decoder (D) All the above
2. Which pins are general purpose I/O pins during mode-2 operation of the 8255? [ a ]
(A) PA0 – PA7 (B) PB0-PB7 (C) PC3-PC7 (D) PC0-PC2
3. An example for a D/A converter is IC 1408,DAC0830/DAC0831/DAC0832
4._Port A port of 8255 can be programmed in three modes: mode 0, mode 1, mode 2.
5.The modes used in display mode are left entry mode (type wroter mode) & right entry mode (calculator type mode)
UNIT-4
1.If a memory block uses address range 10000H to 2FFFFh then its capacity is [ b ]
a. 64KB b.128KB c.256KB d.512KB
2. Which Command word of 8259 is used masking interrupts [ c ]
a. ICW1 b.ICW2 c.OCW1 d.OCW2
3. During block transfer mode , the completion of data transfer is indicated by . TC Flag
4.The Seventh (7) bit of the Control word register of 8257 is used for enabling auto load facility.
5.The Instruction of 8257 used to disable CPU address is AEN.
6.The number of 8259s required to service 64 interrupts is Nine (9)
7.. The command word used to differentiate master and slave is ICW3.
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