The character LCDs are the most commonly used display modules. These LCDs are used to display text using alphanumeric and special characters of font 5×7/5×10. For basic working and operations of a character LCD, refer LCD interfacing with 8051. Here PIC18F4550 has been used to display a single character on a 16×2 character LCD.
For basic details and operations of character LCD, refer LCD interfacing with 8051. Here LCD has been interfaced in 8-bit mode* with data pins (D0-D7) connected to PortB of PIC18F4550. The LCD control pins RS, R/W and EN are connected to PortA pins RA0, RA1 and RA2 respectively.
*Character LCD can also be interfaced by using only 4 data lines. Refer LCD interfacing in 4-bit mode.
Programming Steps:
Before displaying anything on LCD, it needs to be configured with proper instructions. The following programming steps explain the procedure of configuring the LCD and display a character on it.
Step 1: Initialize the LCD.
The LCD must be initialized the by following pre-defined commands of character LCD.
· 0x38, to configure the LCD for 2-line, 5×7 font and 8-bit operation mode
· 0x0C, for Display On and Cursor Off
· 0x01, to Clear Display screen
· 0x06, to increment cursor
· 0x80, to set cursor position at first block of the first line of LCD.
The above set of commands is written in lcd_ini() function of the adjoining code.
Step 2: Send the commands to LCD.
· Send the command byte to the port connected to LCD data pins
· RS=0, to select command register of LCD
· RW=0, to set the LCD in writing mode
· EN=1, a high to low pulse to latch command instruction
· Delay of 1ms
· EN=0
The above set of commands is written in lcdcmd(unsigned char) function.
Step 3: Send data to LCD.
· Send data at the port which connected to LCD data pins
· RS=1, register select to select data register of LCD
· RW=0, this set the LCD in writing mode
· EN=1, a high to low pulse to latch data
· Delay of 1ms
· EN=0
The lcddata(unsigned char) function has the above set of instructions.
For more detail: How to interface LCD with PIC18F4550 Microcontroller
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