Engineering Questions with Answers - Multiple Choice Questions

MCQs on Digital Inputs, Outputs and Delays

1 - Question

Which of the following registers are related to port P1?
a) P1SEL
b) P1DIR
c) P1IES
d) All of the mentioned

View Answer

Answer: d
Explanation: All of the mentioned registers are related to Port1.
P1SEL → Port Select Port pins are often multiplexed with other peripheral module functions. P1SEL and P1SEL2 bit is used to select the pin function – I/O port or peripheral module function.
P1DIR → Direction register selects the direction of the corresponding I/O pin.
P1IES → Interrupt Edge Select.




2 - Question

A pull-up or pull-down resistor ___________
a) removes the full output drive on the output pin
b) gives only a feeble current through the pull-up to resistor
c) removes the full output drive on the output pin & gives only a feeble current through the pull-up to resistor
d) none of the mentioned

View Answer

Answer: c
Explanation: A pull-up or pull-down resistor is used to remove the full output drive on the output pin. It also gives a feeble current through the pull-up to a resistor.




3 - Question

P1.3 is the ___________
a) input CCI1A to Timer_A
b) is connected to the voltage reference VREF of SD16_A
c) is output TA0 from Timer_A
d) are digital inputs with pull-up resistors

View Answer

Answer: b
Explanation: P1.3 is connected to the voltage reference VREF of SD16_A.




4 - Question

What actually is SD16_A?
a) it is an interrupt
b) it is a timer
c) it is an analog to Digital Converter
d) it is a serial communication module

View Answer

Answer: c
Explanation: SD16_A is an analog to the digital module.




5 - Question

P1IE and P1IES are registers that are used to ___________
a) control the Port1 digital i/o ports
b) control the Port1 interrupts
c) control the Port1 serial communication interfaces
d) all of the mentioned

View Answer

Answer: b
Explanation: P1IE and P1IES both registers are used to control the Port1 interrupts.




6 - Question

Unused pins must never be left unconnected in their default state as inputs.
a) true
b) false
c) cant be said
d) depends on the conditions

View Answer

Answer: a
Explanation: Unused pins must never be left unconnected in their default state as inputs. This follows a general rule that inputs to CMOS must never be left unconnected or “floating”.




7 - Question

Which of the following is an effect of a Schmidt trigger?
a) it turns slowly varying inputs, which might cause problems while they pass slowly through the undefined range of input voltages, into abrupt, clean logical transitions
b) It eliminates the effect of noise on the input, provided that it is not large enough to span the gap between the upward and downward thresholds
c) none of the mentioned
d) all of the mentioned

View Answer

Answer: d
Explanation: Schmidt trigger has two of the above mentioned effects in it.




8 - Question

To ensure that a negative fluctuation does not trigger an unwanted downward transition by pulling the input down through VIT−, we must choose
a) minimum hysteresis
b) maximum hysteresis
c) all of the mentioned
d) none of the mentioned

View Answer

Answer: a
Explanation: To ensure that a negative fluctuation does not trigger an unwanted downward transition by pulling the input down through VIT−, we must choose a minimum hysteresis of 0.3V.




9 - Question

The SPDT switch can be used as a ___________
a) detecting circuit
b) debouncing circuit
c) devaluing circuit
d) degenerating circuit

View Answer

Answer: b
Explanation: The SPDT(single pole, double pole) switch can be used as a debouncing circuit of a switch.




10 - Question

Debouncing can be carried out at a hardware as well as the software end?
a) yes
b) no
c) cant be said
d) depends on the conditions

View Answer

Answer: a
Explanation: Debouncing can be carried out at both the fronts both at the software as well as the hardware front, to carry out the process appropriately.

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