Engineering Questions with Answers - Multiple Choice Questions

MCQs on Interfacing I/O Ports

1 - Question

The device that enables the microprocessor to read data from the external devices is
a) printer
b) joystick
c) display
d) reader

View Answer

Answer: b
Explanation: Since joystick is an input device, it reads data from the external devices.




2 - Question

The example of output device is
a) CRT display
b) 7-segment display
c) Printer
d) All of the mentioned

View Answer

Answer: d
Explanation: The output device transfers data from the microprocessor to the external devices.




3 - Question

The input and output operations are respectively similar to the operations,
a) read, read
b) write, write
c) read, write
d) write, read

View Answer

Answer: c
Explanation: The input activity is similar to read operation and the output activity is similar to write operation.




4 - Question

The operation, IOWR (active low) performs
a) write operation on input data
b) write operation on output data
c) read operation on input data
d) read operation on output data

View Answer

Answer: b
Explanation: IOWR (active low) operation means writing data to an output device and not an input device.




5 - Question

The latch or IC 74LS373 acts as
a) good input port
b) bad input port
c) good output port
d) bad output port

View Answer

Answer: c
Explanation: If the output port is to source large currents, the port lines must be buffered. So, the latch is used as it acts as a good output port.




6 - Question

While performing read operation, one must take care that much current should not be
a) sourced from data lines
b) sinked from data lines
c) sourced or sinked from data lines
d) sinked from address lines

View Answer

Answer: c
Explanation: More current should not be sourced or sinked from data lines while reading to avoid loading.




7 - Question

To avoid loading during read operation, the device used is
a) latch
b) flipflop
c) buffer
d) tristate buffer

View Answer

Answer: d
Explanation: A tristate buffer is used as an input device to overcome loading.




8 - Question

The chip 74LS245 is
a) bidirectional buffer
b) 8-bit input port
c) one that has 8 buffers
d) all of the mentioned

View Answer

Answer: d
Explanation: The chip 74LS245 is a bidirectional buffer that contains 8 buffers and may be used as an 8-bit input port. But while using as an input device, only one direction is useful.




9 - Question

In 74LS245, if DIR is 1, then the direction is from
a) inputs to outputs
b) outputs to inputs
c) source to sink
d) sink to source

View Answer

Answer: a
Explanation: If DIR is 1, then the direction is from A(inputs) to B(outputs).




10 - Question

In memory-mapped scheme, the devices are viewed as
a) distinct I/O devices
b) memory locations
c) only input devices
d) only output devices

View Answer

Answer: b
Explanation: In memory-mapped scheme, the devices are viewed as memory locations and are addressed likewise.

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