AVR microcontroller Serial Port Communication mcq

 Serial Port Communication

1. What actually are the DB9, DB25 ports available in our computers?

a) they are connectors used to transfer data either serially or parallelly

b) they are the RS232 connectors used to connect two incompatible devices

c) they are the TTL logic connector pins used for communication

d) they are just data transfer pins used to transfer the data

Answer: they are the RS232 connectors used to connect two incompatible devices

2. What does RI handshaking signal refer to according to the RS232 logic?

a) if this logic is high then a receive interrupt is generated

b) this pin is high during transmission

c) this pin is high during a reception in order to tell that the device is busy at this particular time

d) none of the mentioned

Answer: this pin is high during a reception in order to tell that the device is busy at this particular time

3. What is the major difference between a MAX232 and a MAX233 device?

a) one has one serial port other has two

b) one has inbuilt UART other doesn’t have that

c) one needs some additional circuitry to operate while the other doesn’t have that

d) one is used just for transmission while the other is used for both transmission as well as reception

Answer: one needs some additional circuitry to operate while the other doesn’t have that

4. Which of the following is correct about the baud rate during serial transmission?

a) it tells us about the speed at which the transmission is going to place

b) it tells us about the number of bits transferred during a second

c) none of the mentioned

d) all of the mentioned

Answer: all of the mentioned

5. With fosc=8 MHz, what will the count that has to filled in the UBRR register to account for the 9600 baud rate?

a) 67H

b) CEH

c) 33H

d) 34H

Answer: 33H

6. The USART in AVR based microcontrollers operate at which of the following modes?

a) double speed asynchronous mode

b) master synchronous

c) slave synchronous

d) all of the mentioned

Answer: all of the mentioned

7. Which bit of the UCSRA is used for doubling the baud rate of the transmission?

a) DOR

b) PE

c) U2X

d) MPCM

Answer: U2X

8. What is the use of the PE and the FE bits of the UCSRA register?

a) they are used for keeping a check at the speed of transmission and reception

b) they are used for keeping a check at the data bits to be transferred

c) they are used to keep the transmission error free

d) they are used as extra redundant bits with no use

Answer: they are used to keep the transmission error free

9. Which of the following bits are used for setting the data frame size?

a) UCSZ0

b) U2X

c) DOR

d) MPCM

Answer: UCSZ0

10. Which of the following parameters should the transmitter and the receiver agree upon before starting a serial transmission?

a) baud rate

b) frame size

c) stop bit

d) all of the mentioned

Answer: all of the mentioned