Microprocessors and Microcontrollers (3160914) MCQs

MCQs of 8051 Interrupts

Showing 11 to 20 out of 33 Questions
11.

Which of the following is an external interrupt?

(a)

INT0(active low)

(b)

INT2(active low)

(c)

Timer0 interrupt

(d)

Timer1 interrupt

Answer:

Option (a)

12.

The interrupts, INT0(active low) and INT1(active low) are processed internally by flags

(a)

IE0 and IE1

(b)

IE0 and IF1

(c)

IF0 and IE1

(d)

IF0 and IF1

Answer:

Option (a)

13.

The flags IE0 and IE1, are automatically cleared after the control is transferred to respective vector if the interrupt is

(a)

level-sensitive

(b)

edge-sensitive

(c)

in serial port

(d)

in parallel port

Answer:

Option (b)

14.

If the external interrupt sources control the flags IE0 and IE1, then the interrupt programmed is

(a)

level-sensitive

(b)

edge-sensitive

(c)

in serial port

(d)

in parallel port

Answer:

Option (a)

15.

The pulses at T0 or T1 pin are counted in

(a)

timer mode

(b)

counter mode

(c)

idle mode

(d)

power down mode

Answer:

Option (b)

16.

In timer mode, the oscillator clock is divided by a prescalar

(a)

1/8

(b)

1/4

(c)

1/16

(d)

1/32

Answer:

Option (d)

17.

The serial port interrupt is generated if

(a)

RI is set

(b)

RI and TI are set

(c)

Either RI or TI is set

(d)

RI and TI are reset

Answer:

Option (c)

18.

In serial port interrupt, after the control is transferred to the interrupt service routine, the flag that is cleared is

(a)

RI

(b)

TI

(c)

RI and TI

(d)

None

Answer:

Option (d)

19.

The atleast number of machine cycles for which the external interrupts that are programmed level-sensitive should remain high is

(a)

1

(b)

2

(c)

3

(d)

0

Answer:

Option (b)

20.

If the external interrupts are programmed edge sensitive, then they should remain high for atleast

(a)

0 machine cycle

(b)

2 machine cycles

(c)

1 machine cycle

(d)

3 machine cycles

Answer:

Option (c)

Showing 11 to 20 out of 33 Questions