MPMC MCQ 8051 APPS

In the attached circuit, K1 and K8 are closed where K1 is LSB. Other keys are open. The input value read in Port 1 is

• FFH

• 18H

• 81H

• 00H

In the attached circuit, all keys are open. The input value read in Port 1 is

• FFH

• 18H

• 81H

• 00H

In the attached program, the microcontroller,

• Waits for a key to be pressed

• Waits for a key to be released

• Clears the accumulator

• Waits for a delay to be over

Consider the following statements:

1) LCALL can call a subroutine anywhere within the 2K memory page.

2) ACALL can call a subroutine within 128 bytes memory space.

• Both statements are true.

• Both statements are false

• First statement is true, second statement is false

• First statement is false, second statement is true.

Consider the following statements: The advantage in

organising keys of a keyboard in matrix form are,

1) It reduces the number of port pins required.

2) Only input pins will be required.

• Both statements are true.

• Both statements are false

• First statement is true, second statement is false

• First statement is false, second statement is true.

DPTR=3000H; A = 05H; What is the content of the accumulator after execution of the instruction

MOVC , @A+DPTR

• 30H

• 05H

• 00H

• May not be any of the above

DPTR=3000H; A = 05H; PC=2000H; What is the content of the accumulator after execution of the instruction

MOVC , @A+PC

• 30H

• 05H

• 20H

• May not be any of the above

In the attached circuit for a matrix keyboard interfaced with 8051, P1=F0H; If Key1 is pressed, the content of P2 is

• FFH;

• 0CH;

• FCH

• 00H;

In the attached circuit for a matrix keyboard interfaced with 8051, P1=00H; If Key 7 is pressed, the content of P2 is

• FFH;

• 0CH;

• F7H

• 00H;

In the attached circuit for a matrix keyboard interfaced with 8051, the lookup table contains

• the decimal numbers 00 to 15

• the hexadecimal numbers 0 to F

• the ascii code of the numbers 0 to F

• None of the above