Engineering Questions with Answers - Multiple Choice Questions

MCQs on Low Power Modes

1 - Question

There are how many MSP430’s low power modes available in the chip?
a) two
b) three
c) four
d) five

View Answer

Answer: d
Explanation: There are five low power modes available in the MSP430, out of which two are rarely employed in the current devices.




2 - Question

Which of the following are the low power modes?
a) LPM0
b) LPM3
c) LPM4
d) All of the mentioned

View Answer

Answer: d
Explanation: LPM0, LPM3, LPM4 all are the low power modes that are available in the MSP430.




3 - Question

Which of the following modes is also known as the RAM retention mode?
a) LPM0
b) LPM3
c) LPM4
d) All of the mentioned

View Answer

Answer: c
Explanation: LPM4 is known as the RAM retention mode. Here, the CPU and all clocks are disabled, I ≈ 0.1A. The device can be woken only by an external signal.




4 - Question

Waking a device simply means that switching that device’s operation from a low power mode to an active mode.
a) true
b) false
c) cant be said
d) depends on the conditions

View Answer

Answer: a
Explanation: When a device is operating in a low power mode, it can also be assumed that the device is sleeping, so waking a device simply means to turn that device’s operation from a low power mode to an active mode.




5 - Question

When an interrupt is accepted, the contents of the status register are ___________
a) set
b) reset
c) remains the same
d) cant be said

View Answer

Answer:b
Explanation: When an interrupt is accepted, the contents of the status register are cleared, it actually puts the processor in the active mode.




6 - Question

Which of the following basic clock modules supplies clock signals to the MSP430?
a) ACLK
b) MCLK
c) SMCLK
d) All of the mentioned

View Answer

Answer: d
Explanation: All of the mentioned options are correct. The basic clock module supplies the MSP430 with three clock signals as follows:
ACLK → crystal oscillator signal
MCLK → controllers main system clock
SMCLK → sub main system clock used to run the peripheral module function.




7 - Question

_ _low_ power_mode_0() states the processor to __________
a) enable the interrupt
b) disable the interrupt
c) nothing
d) to go in an active mode

View Answer

Answer: a
Explanation: _ _low_ power_mode_0() puts the processor in the LPM0 mode.




8 - Question

More power can be saved by using low_power mode 0 than low_power mode 3.
a) true
b) false
c) cant be said
d) depends on the conditions

View Answer

Answer: b
Explanation: More power is saved in low_ power mode 3.




9 - Question

_BIC_SR_IRQ() is used to _______________
a) set the particular bits of the SR
b) reset the particular bits of the SR
c) any of the above mentioned depending on the conditions
d) none of the mentioned

View Answer

Answer: b
Explanation: _BIC_SR_IRQ() is used to clear the bits of the SR.




10 - Question

The only clock that runs in the LPM3 is the ___________
a) MCLK
b) ACLK
c) CLK
d) None of the mentioned

View Answer

Answer: b
Explanation: The only clock that runs in the LPM3 is the ACLK.

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