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Microprocessors Solved MCQs

These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Computer Science Engineering (CSE) , Electrical Engineering , Electronics and Communication Engineering .

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1.

for i/o of 8255,if -----, the word is taken as a bit set/rest word

A. D7=1
B. D7=0
C. D0=1
D. D0=0
Answer» B. D7=0
discuss
2.

on activation of ----, 8255 loads data from the input port lines into the input buffer of that port

A. STB#
B. IBF
C. OBF#
D. none of these
Answer» B. IBF
discuss
3.

8255 has three ----parrallel port

A. 8bit
B. 16bit
C. 32bit
D. 64bit
Answer» A. 8bit
discuss
4.

in ----, bidirectional data transfer is possible

A. mode 0
B. mode1
C. mode2
D. BSR
Answer» C. mode2
discuss
5.

walkie-talkie is an example of …..serial communication

A. Simplex
B. Half duplex
C. Full Duplex
D. none of these
Answer» B. Half duplex
discuss
6.

Transmission through telephone lines is an example of….serial commuincation

A. Simplex
B. Half duplex
C. Full Duplex
D. none of these
Answer» C. Full Duplex
discuss
7.

Asynchronous serial communication involves

A. start bit
B. stop bits
C. character data
D. all of these
Answer» D. all of these
discuss
8.

to configure 8255 with port A output,Port B input port C lower output and port C upper input

A. Mov al,0AFH
B. mov al,0AEH
C. mov Al,0CEH
D. Mov A,0AAH
Answer» B. mov al,0AEH
discuss
9.

A high on ---line indicates that the buffer register is empty

A. TXRDY
B. TXE
C. TXC#
D. both B and C
Answer» B. TXE
discuss
10.

Adc 0808 uses ----technique

A. Successive apraximation
B. single step
C. dual slope
D. flash converter
Answer» A. Successive apraximation
discuss
11.

the signals provided by ADC are

A. SOC
B. EOC
C. ALE
D. all of these
Answer» D. all of these
discuss
12.

Flash ADC consist of….converters

A. 2^n
B. 2^n -1
C. 2^n +1
D. none of these
Answer» B. 2^n -1
discuss
13.

8253/54 has ----independent timers/counters

A. 1
B. 2
C. 3
D. 4
Answer» C. 3
discuss (1)
14.

8253/54 timers can be programmed in---modes

A. 1
B. 3
C. 6
D. 5
Answer» C. 6
discuss
15.

in mode 0 of 8253/54 ----disables counting

A. gate=1
B. gate=0
C. wr#=1
D. wr#=0
Answer» B. gate=0
discuss
16.

8253/54 has c----command that allows the user to check the count value programmed mode and current status of the counter

A. write back
B. write ahead
C. read ahead
D. read back
Answer» D. read back
discuss
17.

for mode 3 of 8253/54, if the count is odd the output will be high for---

A. 2/(n+1)
B. (n+1)/2
C. 2/(n-1)
D. (n-1)/2
Answer» B. (n+1)/2
discuss
18.

EOC means

A. End of Conversion
B. Enable output conversion
C. error of conversion
D. none of these
Answer» A. End of Conversion
discuss
19.

ADC 0808 is ----- pin IC

A. 40
B. 20
C. 24
D. 28
Answer» D. 28
discuss
20.

ADC 0808 operates on single ---- power supply

A. 5V
B. 10V
C. 15V
D. 20V
Answer» A. 5V
discuss
21.

8255 has -------- i/o pins

A. 28
B. 26
C. 24
D. 22
Answer» C. 24
discuss
22.

8255 has three ----parallel ports

A. 8 bit
B. 16 bit
C. 32 bit
D. 64 bit
Answer» A. 8 bit
discuss
23.

In 8255 ,BSR means -----

A. bit set/reset
B. byteset/reset
C. binary set/reset
D. none
Answer» A. bit set/reset
discuss
24.

BSR mode is used to set or reset the bitsin

A. portA
B. portB
C. portC
D. portD
Answer» C. portC
discuss
25.

8255 has ----i/o modes

A. 2
B. 3
C. 4
D. 8
Answer» B. 3
discuss
26.

A high on ----pin causes all 24 lines of three 8 bit ports to be in the input mode

A. WR\
B. RESET
C. GND
D. Vcc
Answer» B. RESET
discuss
27.

For i/o mode of 8255,if -----,the word is taken as a mode definition word

A. D7=1
B. D7=0
C. D0=1
D. D0=0
Answer» A. D7=1
discuss
28.

For i/o mode of 8255 ,if -----, the word is taken as a bit set/reset word

A. D7=1
B. D7=0
C. D0=1
D. D0=0
Answer» B. D7=0
discuss
29.

On activation of --------,8255 loads data from the input port lines into the input buffer of that port

A. STB\
B. IBF
C. OBF\
D. NONE
Answer» B. IBF
discuss
30.

IBF is an active-------- output signal for 8255

A. high
B. low
C. enable
D. disable
Answer» A. high
discuss
31.

8255 sets INTR when STB'=-----,IBF=---------,INTE=--------,for input conrol signals

A. 1,0,1
B. 1,1,0
C. 1,1,1
D. 0,1,1
Answer» C. 1,1,1
discuss
32.

Upon activation of------ signal,output device reads data from output port and acknowledges it

A. INTR
B. ACK\
C. OBF\
D. IBF
Answer» C. OBF\
discuss
33.

In ------ of 8255 ,bidirectionali/o data transfer is possible

A. mode0
B. mode1
C. mode2
D. BSR MODE
Answer» C. mode2
discuss
34.

Walkie-talkie is an example of serial communication

A. simplex
B. half-duplex
C. full-duplex
D. none
Answer» B. half-duplex
discuss
35.

Asynchronous serial communication involves transmission of

A. start bit
B. stop bit
C. character data
D. all
Answer» D. all
discuss
36.

Whichof the following is the fastest ADC

A. DUAL SLOPE
B. successive approximation
C. flash
D. single slope
Answer» C. flash
discuss
37.

To indicate end of conversion ADC 0808/0809 ACTIVATES -----SIGNAL

A. EOC
B. SOC
C. CLK
D. OUTPUT CONTROL
Answer» A. EOC
discuss
38.

Conversion time Tc of successive approximation ADC is given as

A. T(n-1)
B. T(n+1)
C. T(n)
D. T(n+2)
Answer» B. T(n+1)
discuss
39.

Conversion time of ADC 0808 IS

A. 100 ms
B. 100micro sec
C. 100 Ms
D. 100ns
Answer» B. 100micro sec
discuss
40.

ADC 0809 IS A ----- PIN IC

A. 40
B. 20
C. 24
D. 28
Answer» D. 28
discuss

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