It is very important to keep a track of the working of
almost all the automated and semi-automated devices, be it a washing machine,
an autonomous robot or anything else. This is achieved by displaying their
status on a small display module. LCD (Liquid Crystal Display) screen is such a
display module and a 16x2 LCD module is very commonly used. These modules are
replacing seven segments and other multi segment LEDs for these purposes. The reasons
being: LCDs are economical, easily programmable, have no limitation of
displaying special & even custom characters (unlike in seven segments),
animations and so on. LCD can be easily interfaced with a microcontroller to
display a message or status of a device. This topic explains the basics of a
16x2 LCD and how it can be interfaced with AT89C51 to display a character.
A 16x2 LCD means it can display 16 characters per line and
there are 2 such lines. In this LCD each character is displayed in 5x7 pixel
matrix. This LCD has two registers.
1.
Command/Instruction Register - stores the command instructions given to
the LCD. A command is an instruction given to LCD to do a predefined task like
initializing, clearing the screen, setting the cursor position, controlling
display etc.
2. Data Register
- stores the data to be displayed on the LCD. The data is the ASCII value of
the character to be displayed on the LCD.
Commonly used LCD Command codes:
Hex Code Command to LCD Instruction Register
1 Clear
screen display
2 Return
home
4 Decrement
cursor
6 Increment
cursor
E Display
ON, Cursor ON
80 Force the
cursor to the beginning of the 1st line
C0 Force
cursor to the beginning of the 2nd line
38 Use 2
lines and 5x7 matrix
If you want to C Code and more details about this circuit write your email id in comment box.we will send you details.
muruganbalamoorthy@gmail.com
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