Question 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

Accepted Answer

For the 8255 Programmable Peripheral Interface (PPI), when D7=0 in the control word, the word is interpreted as a Bit Set/Reset command. This allows for individual bits in the ports to be set or reset without affecting the other bits.

Question 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

Accepted Answer

B

Question 3

8255 has three ----parrallel port
A)8bit
B)16bit
C)32bit
D)64bit

Accepted Answer

8255 is a programmable peripheral interface device designed with three 8-bit parallel ports.

Question 4

in ----, bidirectional data transfer is possible
A)mode 0
B)mode1
C)mode2
D)BSR

Accepted Answer

Mode 2 allows for bidirectional data transfer in the 8255 Programmable Peripheral Interface.

Question 5

walkie-talkie is an example of …..serial communication
A)Simplex
B)Half duplex
C)Full Duplex
D)none of these

Accepted Answer

Walkie-talkies operate on a half-duplex channel, meaning that only one person can talk at a time, but both parties can transmit and receive communications.

Question 6

Transmission through telephone lines is an example of….serial commuincation
A)Simplex
B)Half duplex
C)Full Duplex
D)none of these

Accepted Answer

Telephone lines typically support full duplex communication, allowing both parties to speak and listen at the same time.

Question 7

Asynchronous serial communication involves
A)start bit
B)stop bits
C)character data
D)all of these

Accepted Answer

Asynchronous serial communication involves a start bit to signal the beginning of a transmission, stop bits to signal the end, and the character data being transmitted, thus involving all of these elements.

Question 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

Accepted Answer

The correct configuration for 8255 with Port A as output, Port B as input, Port C lower as output, and Port C upper as input is achieved by setting the control word to 0xAE. This is because the control word format for 8255 is D7 D6 D5 D4 D3 D2 D1 D0, where D7=1 for control word, D6-D5 for Port A mode selection (00 for mode 0), D4 for Port A direction (1 for output), D3-D2 for Port B mode selection (00 for mode 0), D1 for Port B direction (0 for input), and D0 for Port C lower direction (1 for output, with the assumption that Port C upper is input by default in this configuration).

Question 9

A high on ---line indicates that the buffer register is empty
A)TXRDY
B)TXE
C)TXC#
D)both B and C

Accepted Answer

The answer of A high on ---line indicates that the...

Question 10

Adc 0808 uses ----technique
A)Successive apraximation
B)single step
C)dual slope
D)flash converter

Accepted Answer

ADC 0808 uses the Successive Approximation technique for analog to digital conversion.

Question 11

the signals provided by ADC are
A)SOC
B)EOC
C)ALE
D)all of these

Accepted Answer

ADC (Analog-to-Digital Converter) provides various signals for its operation, including SOC (Start of Conversion), EOC (End of Conversion), and ALE (Address Latch Enable). These signals are essential for timing and control purposes in digital systems that interface with analog signals.

Question 12

Flash ADC consist of….converters
A)2^?
B)2^? -1
C)2^? +1
D)none of these

Accepted Answer

A flash ADC consists of 2^n - 1 comparators, where n is the number of bits of the ADC. This is because each comparator is used to compare the input signal to a reference voltage, and for n bits, 2^n - 1 comparators are needed to cover all possible levels.

Question 13

8253/54 has ----independent timers/counters
A)1
B)2
C)3
D)4

Accepted Answer

The 8253/54 chip has 3 independent timers/counters.

Question 14

8253/54 timers can be programmed in---modes
A)1
B)3
C)6
D)5

Accepted Answer

The 8253/54 timer can be programmed in 6 different modes, which are Mode 0 through Mode 5.

Question 15

in mode 0 of 8253/54 ----disables counting
A)gate=1
B)gate=0
C)wr#=1
D)wr#=0

Accepted Answer

In mode 0 of the 8253/54 programmable interval timer, counting is disabled when the gate input is 0. The gate signal controls the start and stop of the counting process.

Question 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

Accepted Answer

The correct command is "read back." This command allows the user to check the count value, programmed mode, and current status of the counter in devices like the 8253/54 programmable interval timer.

Question 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

Accepted Answer

In mode 3 of the 8253/54 timer, which is the square wave generator mode, if the count is odd, the output will be high for (n+1)/2 counts. This is because the mode divides the count into two equal parts, and when the count is odd, the high part is slightly longer.

Question 18

EOC means
A)End of Conversion
B)Enable output conversion
C)error of conversion
D)none of these

Accepted Answer

The answer of EOC means
A)End of Conversion
B)Enable output conversion
C)error of...

Question 19

ADC 0808 is ----- pin IC
A)40
B)20
C)24
D)28

Accepted Answer

The answer of ADC 0808 is ----- pin IC
A)40
B)20
C)24
D)28...

Question 20

ADC 0808 operates on single ---- power supply
A)5V
B)10V
C)15V
D)20V

Accepted Answer

The ADC 0808 is designed to operate on a single 5V power supply, making it compatible with most digital systems without the need for additional voltage regulation.

Quiz 1: I/O, Communication, and Timerscounters of 8255 and ADC 0808

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

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

8255 has three ----parrallel port

in ----, bidirectional data transfer is possible

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

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

Asynchronous serial communication involves

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

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

Adc 0808 uses ----technique

the signals provided by ADC are

Flash ADC consist of….converters

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

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

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

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

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

EOC means

ADC 0808 is ----- pin IC

ADC 0808 operates on single ---- power supply