Custom Characters on LCD using PIC – MikroC

Contents

• 1 DDRAM, CGROM and CGRAM
  • 1.1 CGROM – Character Generator ROM
  • 1.2 DDRAM – Display Data RAM
  • 1.3 CGRAM – Character Generator RAM
• 2 Character Generation using MikroC
  • 2.1 MikroElektronika LCD Custom Char Generator Tool
  • 2.2 MikroC Modified Code
• 3 Circuit Diagram
• 4 Output

These character based LCDs are commonly made using HD44780 compatible controllers. It allows us to define 8 custom characters in addition to the standard pre-programmed characters. In this tutorial we will learn to define our own custom characters using MikroC compiler.

DDRAM, CGROM and CGRAM

CGROM – Character Generator ROM

This is the memory which holds 5×8 or 5×10 dot patterns of predefined characters in the LCD. It can generate 208 5×8 dot character patterns and 32 5×10 dot character patterns.

DDRAM – Display Data RAM

This is the memory which holds the character data which is currently displayed on the LCD screen. Its capacity is 80×8 bits, ie 80 characters.

CGRAM – Character Generator RAM

This memory works similar to CGROM but as this is a RAM we can modify its data any time. So we can store our custom character patterns in this memory through program. We can store up to eight 5×8 character dot patterns or four 5×10 character dot patterns in this memory.

Character Generation using MikroC

You can easily create your own custom characters using MikroElectronika LCD Custom Character Generator Tool.

• Go to Tools >> LCD Custom Character

MikroElektronika LCD Custom Char Generator Tool

MikroElektronika LCD Custom Char Generator

• Set the font size of your LCD
• Set CGRAM Address
• Design your custom character
• Then click on the Generate Code button

This will give you a function to store and display the custom character in the LCD. By changing the CGRAM address you can store up to eight 5×8 custom characters in the LCD memory. You can see a modified MikroC code below, which will store and display 8 custom characters in the LCD.

MikroC Modified Code

// LCD module connections
sbit LCD_RS at RD2_bit;
sbit LCD_EN at RD3_bit;
sbit LCD_D4 at RD4_bit;
sbit LCD_D5 at RD5_bit;
sbit LCD_D6 at RD6_bit;
sbit LCD_D7 at RD7_bit;

sbit LCD_RS_Direction at TRISD2_bit;
sbit LCD_EN_Direction at TRISD3_bit;
sbit LCD_D4_Direction at TRISD4_bit;
sbit LCD_D5_Direction at TRISD5_bit;
sbit LCD_D6_Direction at TRISD6_bit;
sbit LCD_D7_Direction at TRISD7_bit;
// End LCD module connections

const char character0[] = {0,0,10,31,31,14,4,0};
const char character1[] = {14,27,17,17,17,17,31,0};
const char character2[] = {14,27,17,17,17,31,31,0};
const char character3[] = {14,27,17,17,31,31,31,0};
const char character4[] = {14,27,17,31,31,31,31,0};
const char character5[] = {14,31,31,31,31,31,31,0};
const char character6[] = {0,4,2,31,2,4,0,0};
const char character7[] = {0,0,14,17,17,10,27,0};

void CustomChar0() {
  char i;
  Lcd_Cmd(64);
  for (i = 0; i<=7; i++) Lcd_Chr_CP(character0[i]);
  Lcd_Cmd(_LCD_RETURN_HOME);
}

void CustomChar1() {
  char i;
  Lcd_Cmd(72);
  for (i = 0; i<=7; i++) Lcd_Chr_CP(character1[i]);
  Lcd_Cmd(_LCD_RETURN_HOME);
}

void CustomChar2() {
  char i;
  Lcd_Cmd(80);
  for (i = 0; i<=7; i++) Lcd_Chr_CP(character2[i]);
  Lcd_Cmd(_LCD_RETURN_HOME);
}

void CustomChar3() {
  char i;
  Lcd_Cmd(88);
  for (i = 0; i<=7; i++) Lcd_Chr_CP(character3[i]);
  Lcd_Cmd(_LCD_RETURN_HOME);
}

void CustomChar4() {
  char i;
  Lcd_Cmd(96);
  for (i = 0; i<=7; i++) Lcd_Chr_CP(character4[i]);
  Lcd_Cmd(_LCD_RETURN_HOME);
}

void CustomChar5() {
  char i;
  Lcd_Cmd(104);
  for (i = 0; i<=7; i++) Lcd_Chr_CP(character5[i]);
  Lcd_Cmd(_LCD_RETURN_HOME);
}

void CustomChar6() {
  char i;
  Lcd_Cmd(112);
  for (i = 0; i<=7; i++) Lcd_Chr_CP(character6[i]);
  Lcd_Cmd(_LCD_RETURN_HOME);
}

void CustomChar7() {
  char i;
  Lcd_Cmd(120);
  for (i = 0; i<=7; i++) Lcd_Chr_CP(character7[i]);
  Lcd_Cmd(_LCD_RETURN_HOME);
}

void main()  {
  Lcd_Init(); // Initialize LCD

  Lcd_Cmd(_LCD_CLEAR); // Clear display
  Lcd_Cmd(_LCD_CURSOR_OFF); // Cursor off

  //Send Custom Charactors to CGRAM
  CustomChar0();
  CustomChar1();
  CustomChar2();
  CustomChar3();
  CustomChar4();
  CustomChar5();
  CustomChar6();
  CustomChar7();
  //End

  //Display Custom Characters
  Lcd_Chr(1,1,0);
  Delay_ms(1000);
  Lcd_Chr(1,2,1);
  Delay_ms(1000);
  Lcd_Chr(1,3,2);
  Delay_ms(1000);
  Lcd_Chr(1,4,3);
  Delay_ms(1000);
  Lcd_Chr(1,5,4);
  Delay_ms(1000);
  Lcd_Chr(1,6,5);
  Delay_ms(1000);
  Lcd_Chr(1,7,6);
  Delay_ms(1000);
  Lcd_Chr(1,8,7);
  Delay_ms(1000);
}

Circuit Diagram

Interfacing LCD with PIC Microcontroller – Circuit Diagram

Output

LCD Custom Characters