Interfacing KS0108 based 128×64 Graphical LCD with 8051 Microcontroller

Aim:

This tutorial describes how to interface between a 128×64 graphic LCD and an 8-bit
micro-controller. The techniques described here are useful for any other controller type and interfacing technique. The micro-controller is connected via its I/O lines and all signals to the LCD are controlled directly by software.

Description:

Display mapping: Individual pixels can be controlled by writing a byte to a specific address. Each address is mapped to a corresponding set of 8 pixels on the display. Please refer to Figure 1. Note that the order of the columns is reversed. The first byte of data entered after setting the address registers to 0 will appear in the upper right of the display.

The display has 20 pins, numbered from right to left, as we can see in the picture below. It can be used to communicate with the any microcontroller using parallel communication. In this article, where the LCD refresh rate is not a critical point, we will use the parallel communication

The circuit uses a potentiometer (used a 50K) for adjusting the display contrast, and power is made ​​by 5v power supply.

The specification of this LCD are as follows.

• 128 horizontal pixel and 64 vertical pixel resolution.
• Controlled based on KS0108B
• Parallel 8bit interface
• On board graphic memory.
• Available in Green backlight with dark green pixels.
• Also available in Blue backlight with light blue pixels.
• LED backlight.
• 20 PIN linear connection.

---

PIN Description

PIN	Name	Function	Connection with AVR PIN
1	Vss	Ground
2	Vcc	+5v Supply in
3	V0	Contrast Adjust
4	RS	Instruction/Data Register Select	P3.2
5	R/W	READ/WRITE SELECTION	P3.1
6	E	ENABLE SIGNAL	P3.0
7	DB0	DATA IN/OUT	P2.0
8	DB1	DATA IN/OUT	P2.1
9	DB2	DATA IN/OUT	P2.2
10	DB3	DATA IN/OUT	P2.3
11	DB4	DATA IN/OUT	P2.4
12	DB5	DATA IN/OUT	P2.5
13	DB6	DATA IN/OUT	P2.6
14	DB7	DATA IN/OUT	P2.7
15	CS1	Chip Select 1	P3.3
16	CS2	Chip Select 2	P3.4
17	RST	RESET SIGNAL	RESET
18	VEE	NEGATIVE 10V OUT
19	LED+	LED BACKLIGHT
20	LED-	LED BACKLIGHT

Block Diagram

Schematic

Code

Main File:

// *******************************************************
// Project: Interfacing Graphical LCD with 8051
// Author: Code Bloges
// Module description: Operate Graphical LCD
// *******************************************************
#include<reg51.h>
#include<intrins.h>
#define dport P2

sbit rs=P3^0;
sbit rw=P3^1;
sbit en=P3^2;
sbit cs1=P3^3;
sbit cs2=P3^4;

unsigned char c,z=0;
unsigned char ar00[]={127,8,8,8,127};                          //H,5x7
unsigned char ar11[]={126,17,17,17,126};                      //A,5x7
unsigned char ar22[]={62,65,65,65,34};                                   //C,5x7
unsigned char ar33[]={127,8,20,34,65};                                   //K,5x7
unsigned char ar44[]={127,9,9,9,6};                                //P,5x7
unsigned char ar55[]={127,9,25,41,70};                                   //R,5x7
unsigned char ar66[]={62,65,65,65,62};                                   //O,5x7
unsigned char ar77[]={32,64,65,63,1};                          //J,5x7        
unsigned char ar88[]={127,73,73,73,65};                                 //E,5x7
unsigned char ar99[]={1,1,127,1,1};                                //T,5x7
unsigned char ar01[]={70,73,73,73,49};                                   //S,5x7           
unsigned char ar02[]={0,0,0,0,0};                         // ,5x7

void ctrloff()
{
            rs=0;
            rw=0;
            en=0;
            cs1=0;
            cs2=0;
}
//Display on function                         
void displayon()
{ 
            ctrloff();
            dport=0x3f;  
            cs1=1;cs2=1;
            rw=0;rs=0;
            en=1;
            _nop_(); 
            en=0;
}
void setcolumn(unsigned char y)
{
            if(y<64)
            {
                        ctrloff();
                        c=y;
                        dport=0x40|(y&63);      //0x40 represents Column 0
                        cs1=1;cs2=0;
                        rs=0;
                        rw=0;
                        en=1;
                        _nop_(); 
                        en=0;
            }
            else
            { 
                        c=y;
                        dport=0x40|((y-64)&63);       //0x40 represents Column 0
                        cs2=1;cs1=0;
                        rs=0;
                        rw=0;
                        en=1;
                        _nop_(); 
                        en=0;
            }
}
void setpage(unsigned char x)
{
            ctrloff();
            dport= 0xb8|x;       //0xb8 represents Page 0
            cs1=1;
            cs2=1;
            rs=0;
            rw=0;
            en=1;
            _nop_(); 
            en=0;
}
void lcddata(unsigned char *value,unsigned int limit)
{
            unsigned int i;
            for(i=0;i<limit;i++)
            {
                        if(c<64)
                        {
                                    dport=value[i];
                                    cs1=1;cs2=0;
                                    rs=1;
                                    rw=0;
                                    en=1;
                                    _nop_(); 
                                    en=0;
                                    c++;
                        }
                        else
                        {
                                    setcolumn(c); 
                                    dport=value[i];
                                    cs2=1;cs1=0;
                                    rs=1;
                                    rw=0;
                                    en=1;
                                    _nop_(); 
                                    en=0;
                                    c++;
                        }
            if(c>127)
            return;
            }
}
void clrlcd()
{
    unsigned char i,j;
    for (i=0;i < 8;i++)
    {
            setpage(i);
            setcolumn(0);
            for (j= 0 ;j < 128; j++)
           lcddata(&z,1);
    }
}
void main()
{ 
            clrlcd();                  
            displayon(); 
            setpage(3);
            setcolumn(0);
            lcddata(&ar00,5);
            setpage(3);
            setcolumn(6);
            lcddata(&ar11,5);
            setpage(3);
            setcolumn(12);
            lcddata(&ar22,5); 
            setpage(3);
            setcolumn(18);
            lcddata(&ar33,5); 
            setpage(3);
            setcolumn(24);
            lcddata(&ar02,5);
            setpage(3);
            setcolumn(30);
            lcddata(&ar44,5);
            setpage(3);
            setcolumn(36);
            lcddata(&ar55,5);
            setpage(3);
            setcolumn(42);
            lcddata(&ar66,5);
            setpage(3);
            setcolumn(48);
            lcddata(&ar77,5); 
            setpage(3);
            setcolumn(54);
            lcddata(&ar88,5);         
            setpage(3);
            setcolumn(60);
            lcddata(&ar22,5);         
            setpage(3);
            setcolumn(66);
            lcddata(&ar99,5);  
            setpage(3);
            setcolumn(72);
            lcddata(&ar01,5);
            while(1)
            {
            } 
}

Downloads:

The code was compiled in Keil uvision4 and simulation was made in Proteus v7.7.
To download code and proteus simulation click here.

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