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- Question
The most widespread application of ROMs is in the storage of data and program codes that must be available on power-down in the microprocessor-based systems. These data and program codes are called firmware because they are firmly stored in hardware.
Options- A. True
- B. False
- Correct Answer
- False
- 1. Design a circuit using a 74121 to convert a 33-kHz, 30% duty cycle waveform to a 33-kHz, 60% duty cycle waveform.
Options- A. Rint = 2 kΩ, Cext = 0.012 nF
- B. Rint = 2 kΩ, Cext = 0.012 µF
- C. Rint = 4 kΩ, Cext = 0.012 nF
- D. Rint = 4 kΩ, Cext = 0.012 µF Discuss
- 2. What is the difference between a retriggerable one shot and a nonretriggerable one shot?
Options- A. The nonretriggerable can only be triggered once.
- B. The retriggerable can be triggered many times.
- C. The output pulse can be stretched with a nonretriggerable.
- D. The output pulse can be stretched with a retriggerable. Discuss
- 3. Which of the following commands will copy the contents of RAM whose address is in register 0 to port 1?
Options- A. MOV @ P1, R0
- B. MOV @ R0, P1
- C. MOV P1, @ R0
- D. MOV P1, R0 Discuss
- 4. Which of the following instructions will load the value 35H into the high byte of timer 0?
Options- A. MOV TH0, #35H
- B. MOV TH0, 35H
- C. MOV T0, #35H
- D. MOV T0, 35H Discuss
- 5. The I/O ports that are used as address and data for external memory are:
Options- A. ports 1 and 2
- B. ports 1 and 3
- C. ports 0 and 2
- D. ports 0 and 3 Discuss
- 6. To interface external EPROM memory for applications, it is necessary to demultiplex the address/data lines of the 8051.
Options- A. True
- B. False Discuss
- 7. The designs of a centigrade thermometer and a PWM speed-control circuit can be implemented by the 8051.
Options- A. True
- B. False Discuss
- 8. Device pins XTAL1 and XTAL2 for the 8051 are used for connections to an external oscillator or crystal.
Options- A. True
- B. False Discuss
- 9. 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
Options- A. True
- B. False Discuss
- 10. The 8051 can handle ________ interrupt sources.
Options- A. 3
- B. 4
- C. 5
- D. 6 Discuss
More questions
Correct Answer: Rint = 2 kΩ, Cext = 0.012 µF
Correct Answer: The output pulse can be stretched with a retriggerable.
Correct Answer: MOV P1, @ R0
Correct Answer: MOV TH0, #35H
Correct Answer: ports 0 and 2
Correct Answer: True
Correct Answer: True
Correct Answer: True
Correct Answer: True
Correct Answer: 5
Explanation:
There are five interrupt sources for the 8051, which means that they can recognize 5 different events that can interrupt regular program execution. Each interrupt can be enabled or disabled by setting bits of the IE register. Likewise, the whole interrupt system can be disabled by clearing the EA bit of the same register.
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