Monday 23 July 2018

Interfacing KS0108 based 128×64 Graphical LCD with PIC Microcontroller (PIC18F4520)

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
1VssGround
2Vcc+5v Supply in
3V0Contrast Adjust
4RSInstruction/Data Register SelectRA.0
5R/WREAD/WRITE SELECTIONRA.1
6EENABLE SIGNALRA.2
7DB0DATA IN/OUTRB.0
8DB1DATA IN/OUTRB.1
9DB2DATA IN/OUTRB.2
10DB3DATA IN/OUTRB.3
11DB4DATA IN/OUTRB.4
12DB5DATA IN/OUTRB.5
13DB6DATA IN/OUTRB.6
14DB7DATA IN/OUTRB.7
15CS1Chip Select 1RA.3
16CS2Chip Select 2RA.5
17RSTRESET SIGNALRESET
18VEENEGATIVE 10V OUT
19LED+LED BACKLIGHT
20LED-LED BACKLIGHT

Block Diagram

glcd

Schematic


Code

Main File:

// *******************************************************
// Project: Interfacing Graphical LCD with 8051
// Author: Hack Projects India
// Module description: Operate Graphical LCD
// *******************************************************

#include <p18f4520.h>
#include <delays.h>
#pragma config OSC=HS, FCMEN=ON, WDT=OFF, IESO=OFF, XINST=OFF, LVP=OFF
#define dport PORTB
#define rs PORTAbits.RA0
#define rw PORTAbits.RA1
#define en PORTAbits.RA2
#define cs1 PORTAbits.RA3
#define cs2 PORTAbits.RA5

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;
 Delay10TCYx(10);
 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;
  Delay10TCYx(10);
  en=0;
 }
 else
 {
  c=y;
  dport=0x40|((y-64)&63);   //0x40 represents Column 0
  cs2=1;cs1=0;
  rs=0;
  rw=0;
  en=1;
  Delay10TCYx(10);
  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;
 Delay10TCYx(10);
 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;
   Delay10TCYx(10);
   en=0;
   c++;
  }

  else
  {
   setcolumn(c);
   dport=value[i];
   cs2=1;cs1=0;
   rs=1;
   rw=0;
   en=1;
   Delay10TCYx(10);
   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()
{
      ADCON1=0b00001111;
    TRISA=0x00;
    TRISB=0x00;
 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)
 {

 }
}


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