MCQs on Microprocessor and Microcontrollers Part-4

Microprocessor and Microcontrollers

1. Which registers are supposed to get copied into RCAP2H & RCAP2L respectively due to the transition at 8052 T2EX pin in the capture mode operation?

a. TH0 & TH1

b. TH1 & TH1

c. TH2 & TH2

d. All of the above

2. Which mode of timer 2 allow to hold the reload values with an assistance of RCAP2H & RCAP2L register pair?

a. 8 bit auto-reload mode

b. 16 bit auto reload mode

c. 8 bit capture mode

d. 16 bit capture mode

3. Where should the pin 19 (XTAL1), acting as an input of inverting amplifier as well as part of an oscillator circuit, be connected under the application of external clock?

a. to XTAL2

b. to Vcc

c. to GND

d. to ALE

4. Which port does not represent quasi-bidirectional nature of I/O ports in accordance to the pin configuration of 8051 microcontroller?

a. Port 0 (Pins 32-39)

b. Port 1 (Pins 1-8)

c. Port 2 (Pins 21-28)

d. Port 3 (Pins 10-17)

5. What is the required baud rate for an efficient operation of serial port devices in 8051 microcontroller?

a. 1200

b. 2400

c. 4800

d. 9600

6. Which among the below mentioned functions does not belong to the category of alternate functions usually performed by Port 3 (Pins 10-17)?

a. External Interrupts

b. Internal Interrupts

c. Serial Ports

d. Read / Write Control signals

7. What is the constant activation rate of ALE that is optimized periodically in terms of an oscillator frequency?

a. 1 / 8

b. 1 / 6

c. 1 / 4

d. 1 / 2

8. Which output control signal is activated after every six oscillator periods while fetching the external program memory and almost remains high during internal program execution?

a. ALE

b. PSEN

c. EA

d. All of the above

9. Which memory allow the execution of instructions till the address limit of 0FFFH especially when the External Access (EA) pin is held high?

a. Internal Program Memory

b. External Program Memory

c. Both a & b

d. None of the above

10. Which value of disc capacitors is preferred or recommended especially when the quartz crystal is connected externally in an oscillator circuit of 8051?

a. 10 pF

b. 20 pF

c. 30 pF

d. 40 pF

11. Why are the resonators not preferred for an oscillator circuit of 8051?

a. Because they do not avail for 12 MHz higher order frequencies

b. Because they are unstable as compared to quartz crystals

c. Because cost reduction due to its utility is almost negligible in comparison to total cost of microcontroller board

d. All of the above

12. Which version of MCS-51 requires the necessary connection of external clock source to XTAL2 in addition to the XTAL1 connectivity to ground level?

a. HMOS

b. CHMOS

c. CMOS

d. All of the abov

13. Which signal from CPU has an ability to respond the clocking value of D- flipflop (bit latch) from the internal bus?

a. Write-to-Read Signal

b. Write-to-Latch Signal

c. Read-to-Write Signal

d. Read-to-Latch Signal

14. Which among the below mentioned statements are precisely related to quasi-bidirectional port?

a. Fixed high pull-up resistors are internally connected

b. Configuration in the form of input pulls the port at higher position whereas they get pulled lower when configured as a source current

c. It is possible to drive the pin as output at any duration when FET gets turned OFF for an input function

d. Upper pull-up FET is always OFF with the provision of ‘open-drain’ output pin for normal operation of port

a. A, B, C, D

b. A, B & C

c. A & B

d. C & D

15. What happens when the pins of port 0 & port 2 are switched to internal ADDR and ADDR / DATA bus respectively while accessing an external memory?

a. Ports cannot be used as general-purpose Inputs/Outputs

b. Ports start sinking more current than sourcing

c. Ports cannot be further used as high impedance input

d. All of the above