# 8051 Microcontroller Questions and Answers – LCD Interfacing

This set of 8051 Micro-controller Multiple Choice Questions & Answers (MCQs) focuses on “LCD Interfacing”.

1. How many rows and columns are present in a 16*2 alphanumeric LCD?
a) rows=2, columns=32
b) rows=16, columns=2
c) rows=16, columns=16
d) rows=2, columns=16

Explanation: 16*2 alphanumeric LCD has 2 rows and 16 columns.

2. How many data lines are there in a 16*2 alphanumeric LCD?
a) 16
b) 8
c) 1
d) 0

Explanation: There are eight data lines from pin no 7 to pin no 14 in an LCD.

3. Which pin of the LCD is used for adjusting its contrast?
a) pin no 1
b) pin no 2
c) pin no 3
d) pin no 4

Explanation: Pin no 3 is used for controlling the contrast of the LCD.

4. For writing commands on an LCD, RS bit is
a) set
b) reset
c) set & reset
d) none of the mentioned

Explanation: For writing commands on an LCD, RS pin is reset.

5. Which command of an LCD is used to shift the entire display to the right?
a) 0x1C
b) 0x18
c) 0x05
d) 0x07

Explanation: 0x1C is used to shift the entire display to the right.

6. Which command is used to select the 2 lines and 5*7 matrix of an LCD?
a) 0x01
b) 0x06
c) 0x0e
d) 0x38

Explanation: 0x38 is used to select the 2 lines and 5*7 matrix of an LCD.

7. Which of the following step/s is/are correct for sending data to an LCD?
a) set the R/W bit
b) set the E bit
c) set the RS bit
d) all of the mentioned

Explanation: To send data to an LCD, RS pin should be set so that LCD will come to know that it will receive data which has to display on the screen. R/W pin should be reset as data has to be displayed (i.e. write to the LCD). High to low pulse must be applied to the E pin when data is supplied to data pins of the LCD.

8. Which of the following step/s is/are correct to perform reading operation from an LCD?
a) low to high pulse at E pin
b) R/W pin is set high
c) low to high pulse at E pin & R/W pin is set high
d) none of the mentioned

Explanation: For reading operations, R/W pin should be made high and added to it, a low to high pulse is also generated at the E pin.

9. Which instruction is used to select the first row first column of an LCD?
a) 0x08
b) 0x0c
c) 0x80
d) 0xc0

Explanation: 0x80 is used to select the first row first column of an LCD.

10. The RS pin is _________ for an LCD.
a) input
b) output
c) input & output
d) none of the mentioned

Explanation: The RS pin is an input pin for an LCD.

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