Microcontroller Questions and Answers Part-20

1. Asynchronous serial communication usually requires two wires for each direction plus a common ground.
a) true
b) false
c) cant be said
d) depends on the conditions

Answer: b
Explanation: Asynchronous serial communication usually requires only a single wire for each direction plus a common ground.

2.In an asynchronous mode of transmission, usually the data is sent along with the
a) the start bit
b) the stop bit
c) the start & stop bit
d) none of the mentioned

Answer: c
Explanation: In an asynchronous mode of transmission, both the start and the stop bits are present that are basically used for intimating the other terminal that whether the data had received correctly the other destination or not

3. The _____ rate gives the frequency at which the bits are transmitted on the line.
a) bit rate
b) packet rate
c) baud rate
d) data rate

Answer: c
Explanation: Baud rate is the rate which determines us the frequency at which the bits are transmitted on the line.

4. Baud rate is the reverse of the ________
a) baud time
b) baud period
c) bit time
d) bit period

Answer: b
Explanation: Baud rate is the reverse of the baud period.

5. Clock is transmitted in the asynchronous communication?
a) yes
b) no
c) cant be said
d) depends on the conditions

Answer: b
Explanation: No clock is transmitted in the asynchronous communication, so the transmitter and the receiver are allowed to work independently at their own terminals

6. A framing error occurs is the bit is ________
a) high
b) low
c) same
d) changed

Answer: b
Explanation: Framing error occurs if the bit is low.

7. What is the non return to zero format?
a) the bits are either high or low and have no gaps between them
b) the bits are either high or low and have gaps between them
c) the bits are high and have gaps between them
d) the bits are low and have no gaps between them

Answer: a
Explanation: Non-return to zero format represents a format in which the bits are either high or low and have no gaps between them.

8. LSB is sent first in case of the non return to zero format.
a) true
b) false
c) cant be said
d) depends on the conditions

Answer: a
Explanation: In non-return to zero format, normally LSB is sent first.

9. There are _______ clocks in the USCI_A.
a) 1
b) 2
c) 3
d) 4

Answer: c
Explanation: they are 3 clocks in the USCI_A. They are BRCLK, BITCLK and BITCLK16.

10. BITCLK16 is the ________
a) sampling clock in the undersampling mode
b) sampling clock in the oversampling mode
c) quantising clock in the undersampling mode
d) quantising clock in the oversampling mode

Answer: b
Explanation: BITCLK16 is the sampling clock in the oversampling mode.