The 8051 Microcontroller Questions and Answers

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The 8051 Microcontroller questions with answers provide a comprehensive overview of microcontroller architecture, instruction sets, and I/O programming. These programming questions and answers are key for embedded systems interviews and ECE placements in companies like TCS, DRDO, and Intel. Each question explores the working principles of timers, interrupts, and serial communication in 8051. Practicing these MCQs enhances your embedded system knowledge and coding efficiency in assembly and C languages.

The 8051 Microcontroller

Showing 10 of 59 questions

31. When the 8051 is reset and the EA line is LOW, the program counter points to the first program instruction in the:

  • internal code memory
  • external code memory
  • internal data memory
  • external data memory
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32. The designs of a centigrade thermometer and a PWM speed-control circuit can be implemented by the 8051.

  • TRUE
  • FALSE
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33. What is the difference between the 8031 and the 8051?

  • The 8031 has no interrupts.
  • The 8031 is ROM-less.
  • The 8051 is ROM-less.
  • The 8051 has 64 bytes more memory.
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34. To interface external EPROM memory for applications, it is necessary to demultiplex the address/data lines of the 8051.

  • TRUE
  • FALSE
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35. The following command will copy the accumulator to the location whose address is 23H: MOV 23H,A

  • TRUE
  • FALSE
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36. The special function registers can be referred to by their hex addresses or by their register names.

  • TRUE
  • FALSE
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37. The contents of the accumulator after this operation MOV A,#2BH ORL A,00H will be:

  • 1B H
  • 2B H
  • 3B H
  • 4B H
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38. The following program will cause the 8051 to be stuck in a loop: LOOP:     MOV A, #00H      JNZ LOP

  • TRUE
  • FALSE
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39. Which of the following commands will copy the contents of RAM whose address is in register 0 to port 1?

  • MOV @ P1, R0
  • MOV @ R0, P1
  • MOV P1, @ R0
  • MOV P1, R0
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40. The statement CALL READ passes control to the line labelled READ.

  • TRUE
  • FALSE
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