MCQOPTIONS
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MCQOPTIONS
This section includes 133 Mcqs, each offering curated multiple-choice questions to sharpen your Digital Electronics knowledge and support exam preparation. Choose a topic below to get started.
| 101. |
The designs of a centigrade thermometer and a PWM speed-control circuit can be implemented by the 8051. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 102. |
The I/O port that does not have a dual-purpose role is: |
| A. | port 0 |
| B. | port 1 |
| C. | port 2 |
| D. | port 3 |
| Answer» C. port 2 | |
| 103. |
Which of the following commands will move the number 27H into the accumulator? |
| A. | MOV A, P27 |
| B. | MOV A, #27H |
| C. | MOV A, 27H |
| D. | MOV A, @27 |
| Answer» C. MOV A, 27H | |
| 104. |
Which of the following commands will copy the contents of RAM whose address is in register 0 to port 1? |
| A. | MOV @ P1, R0 |
| B. | MOV @ R0, P1 |
| C. | MOV P1, @ R0 |
| D. | MOV P1, R0 |
| Answer» D. MOV P1, R0 | |
| 105. |
Data transfer from I/O to external data memory can only be done with the MOV command. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 106. |
An alternate function of port pin P3.0 (RXD) in the 8051 is: |
| A. | serial port input |
| B. | serial port output |
| C. | memory write strobe |
| D. | memory read strobe |
| Answer» B. serial port output | |
| 107. |
In an 8051 program DA A adjusts the value in the accumulator resulting from an addition into two BCDs. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 108. |
Bit-addressable memory locations are: |
| A. | 10H through 1FH |
| B. | 20H through 2FH |
| C. | 30H through 3FH |
| D. | 40H through 4FH |
| Answer» C. 30H through 3FH | |
| 109. |
A HIGH on which pin resets the 8051 microcontroller? |
| A. | RESET |
| B. | RST |
| C. | PSEN |
| D. | RSET |
| Answer» C. PSEN | |
| 110. |
A Celsius thermometer is an application for the 8051 microcontroller. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 111. |
The 8-bit address bus allows access to an address range of: |
| A. | 0000 to FFFFH |
| B. | 000 to FFFH |
| C. | 00 to FFH |
| D. | 0 to FH |
| Answer» D. 0 to FH | |
| 112. |
To interface external EPROM memory for applications, it is necessary to demultiplex the address/data lines of the 8051. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 113. |
The following command will rotate the 8 bits of the accumulator one position to the left: RL A |
| A. | 1 |
| B. | |
| Answer» B. | |
| 114. |
MOV A, @ R1 will: |
| A. | copy R1 to the accumulator |
| B. | copy the accumulator to R1 |
| C. | copy the contents of memory whose address is in R1 to the accumulator |
| D. | copy the accumulator to the contents of memory whose address is in R1 |
| Answer» D. copy the accumulator to the contents of memory whose address is in R1 | |
| 115. |
The RST pin requires a HIGH to reset the 8051 microcontroller. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 116. |
An alternate function of port pin P3.1 in the 8051 is: |
| A. | serial port input |
| B. | serial port output |
| C. | memory write strobe |
| D. | memory read strobe |
| Answer» C. memory write strobe | |
| 117. |
A label is used to name a single line of code. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 118. |
The 8051 can handle ________ interrupt sources. |
| A. | 3 |
| B. | 4 |
| C. | 5 |
| D. | 6 |
| Answer» D. 6 | |
| 119. |
This program code will be executed once: STAT: MOV A, #01H  JNZ STAT |
| A. | 1 |
| B. | |
| C. | MOV 3R, A |
| D. | MOV R3, A |
| Answer» C. MOV 3R, A | |
| 120. |
Which of the following instructions will load the value 35H into the high byte of timer 0? |
| A. | MOV TH0, #35H |
| B. | MOV TH0, 35H |
| C. | MOV T0, #35H |
| D. | MOV T0, 35H |
| Answer» B. MOV TH0, 35H | |
| 121. |
The contents of the accumulator after this operation MOV A,#2BH ORL A,00H will be: |
| A. | 1B H |
| B. | 2B H |
| C. | 3B H |
| D. | 4B H |
| Answer» C. 3B H | |
| 122. |
Which of the following instructions will move the contents of the accumulator to register 6? |
| A. | MOV 6R, A |
| B. | MOV R6, A |
| C. | MOV A, 6R |
| D. | MOV A, R6 |
| Answer» C. MOV A, 6R | |
| 123. |
This program code will be executed continuously: STAT: MOV A, #01H  JNZ STAT |
| A. | 1 |
| B. | |
| Answer» B. | |
| 124. |
The I/O ports that are used as address and data for external memory are: |
| A. | ports 1 and 2 |
| B. | ports 1 and 3 |
| C. | ports 0 and 2 |
| D. | ports 0 and 3 |
| Answer» D. ports 0 and 3 | |
| 125. |
The address space of the 8051 is divided into four distinct areas: internal data, external data, internal code, and external code. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 126. |
What is the difference between the 8031 and the 8051? |
| A. | The 8031 has no interrupts. |
| B. | The 8031 is ROM-less. |
| C. | The 8051 is ROM-less. |
| D. | The 8051 has 64 bytes more memory. |
| Answer» C. The 8051 is ROM-less. | |
| 127. |
The 8051 has ________ 16-bit counter/timers. |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» C. 3 | |
| 128. |
The microcontroller is useful in systems that have nonvariable programs for dedicated applications. |
| A. | 1 |
| B. | |
| C. | 32K |
| D. | 64K |
| Answer» B. | |
| 129. |
The following program will receive data from port 1, determine whether bit 2 is high, and then send the number FFH to port 3: READ: MOV A,P1 ANL A,#2H CJNE A,#02H,READ MOV P3,#FFH |
| A. | 1 |
| B. | |
| C. | 1 |
| D. | |
| Answer» B. | |
| 130. |
Analog output current must be converted into a usable voltage. To perform this current-to-voltage conversion a 700 op amp may be used. |
| A. | 1 |
| B. | |
| C. | 1 |
| D. | |
| Answer» B. | |
| 131. |
This program code will read data from port 0 and write it to port 2, and it will stop looping when bit 3 of port 2 is set: STAT: MOV A, PO  MOV P2,A  JNB P2.3, STAT |
| A. | 1 |
| B. | |
| C. | MOV P2, R3 |
| D. | MOV R3, P2 |
| Answer» B. | |
| 132. |
Data transfer from I/O to external data memory can only be done with the MOVX command. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 133. |
The internal RAM memory of the 8051 is: |
| A. | 32 bytes |
| B. | 64 bytes |
| C. | 128 bytes |
| D. | 256 bytes |
| Answer» D. 256 bytes | |