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.
Prepared by
Chayadevi