Microprocessors Questions and Answers – Power Control Register

This set of Microprocessor Multiple Choice Questions & Answers (MCQs) focuses on “Power Control Register”.

1. The power control register is
a) used for power saving during idle state
b) used for eventual power off to 8051 chip
c) non-bit addressable register
d) all of the mentioned
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2. The state of signals in idle mode is
a) ALE is high
b) PSEN is high
c) PSEN(active low) is high
d) ALE and PSEN(active low) are high
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3. To come out of idle mode, the external interrupt that is enabled is
a) SI(serial)
b) INT0
c) INT1
d) All of the mentioned
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4. The microcontroller enters into power down mode when
a) SMOD bit of PCON is set
b) GF1 bit of PCON is set
c) PD bit of PCON is set
d) GF2 bit of PCON is set
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5. The clock signal is disabled to all parts of 8051 in
a) normal mode
b) idle mode
c) power down mode
d) addressing mode
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6. During power down to save battery, the supply voltage can be reduced to a value of
a) 4 volts
b) 2 volts
c) 8 volts
d) 1 volt
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7. The signal that only pulls the microcontroller(8051) out of the power down mode is
a) CLEAR
b) LEAVE
c) RESET
d) EXIT
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8. The state of signals in power down mode is
a) ALE is high
b) PSEN is low
c) ALE and PSEN(active low) are high
d) ALE and PSEN(active low) are low
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9. In power down mode,
a) Port pins maintain their logic levels
b) SFRs maintain their logic levels
c) Clock signal is disabled
d) All of the mentioned
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10. The SMOD bit is used to
a) decrease the baud rate by 2
b) increase the baud rate by 4
c) increase the baud rate by 2
d) triple the baud rate
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Sanfoundry Global Education & Learning Series – Microprocessors.

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