This is the code I wrote to drive a 128x64 pixel graphic LCD module based on the KS0107 and KS0108 controllers.

The biggest problem with interfacing this module is the terrible datasheet quality- the timing sequence diagrams are very ambiguous, to say the least. You'll likely want to change the duration of the delay in the _lcd_enable() function to match your chip.

The code is for 18F452 @ 22.118 MHz, and written in Microchip C18. I don't think it'd be too hard to port to other compilers, but YMMV.

I've reluctantly removed the font data, since I do not own it, and cannot freely distribute it. There are many starts for fonts available on this site here:-http://piclist.com/techref/datafile/charsets.htm .

The functions that start _lcd* are intended to be for internal use by the library, whereas lcd* are for your use. Of course, that doesn't limit you in what you do at all.

glcd.h

#include <p18cxxx.h>
#include <delays.h>

#define LCD_TRIS      TRISB
#define LCD_DATA      PORTB
#define ENABLE        PORTDbits.RD7
#define RW            PORTDbits.RD6
#define DI            PORTDbits.RD5
#define RESET         PORTDbits.RD4
#define CS1           PORTDbits.RD2
#define CS2           PORTDbits.RD3
 
#define LEFT          0b01
#define RIGHT         0b10
#define BOTH          0b11
#define NONE          0b00

// internal function prototypes
// 
// you would not normally call these directly. but you can 
// if you like.
void _lcd_enable(void);
unsigned char _lcd_status(void);
void _lcd_reset(void);
void _lcd_waitbusy(void);

// public function prototypes
//
// call these all you want !
void lcd_screenon(unsigned char on);
void lcd_cls(void);
void lcd_setpage(unsigned char page);
void lcd_setyaddr(unsigned char y);
void lcd_selectside(unsigned char sides);
void lcd_write (unsigned char data);
unsigned char lcd_read (void);
void lcd_plotpixel(unsigned char rx, unsigned char ry);
void lcd_putchar(char c);
void lcd_puts(char *string);
void lcd_putrs(const rom char *string);
 
 
 

And now glcd.c :-

#include <p18cxxx.h>
#include "glcd.h"

const rom char font[]= { 
 /* add your own font data
    each char is 3x8 pixels. 3 bytes per char. left column, middle column, right column
 */
};

void _lcd_enable(void)
{
    Delay10TCYx(1);
    ENABLE=1;
    Delay10TCYx(1);
    ENABLE=0;
    Delay10TCYx(1);
}

unsigned char _lcd_status(void)
{
    // returns the lcd status & maintains the TRIS state of the
    // lcd data port

    unsigned char _lcd_tris, _status;

    // save the tris value
    _lcd_tris = LCD_TRIS;
    // read the status
    LCD_TRIS=0xFF; // all inputs
    DI=0; RW=1; // command/read

    _lcd_enable();
    _status = LCD_DATA;
    // restore the tris value
    LCD_TRIS = _lcd_tris;
    
    return _status;
}

void _lcd_reset(void)
{
    // reset the lcd module
    // datasheet says reset must be low for minimum of 1us
    // after Vdd clears 4.5v. 

    // from experimentation, this is bullshit. this seems to
    // work though.
    Delay10TCYx(250); // actually .5 ms
    RESET=1;
    Delay10TCYx(250); // actually .5 ms
    RESET=0;
    // check status, and wait if necessary
    while (_lcd_status() & 0b00010000)
    {
        Delay10TCYx(250); // .5 ms
    }
}
void lcd_screenon(unsigned char on)
{
    // turn the display on or off
    LCD_TRIS=0; // all outputs
    RW=0; DI=0;
    LATB = 0b00111110 | (on & 0b00000001); // main screen turn on!
    _lcd_enable();
}
void lcd_cls(void)
{
    unsigned char x,y;

    for (x=0; x<8; x++)
    {
        // set the page (x)
        lcd_setpage(x);
        // set the y address to 0
        lcd_setyaddr(0);
        // setup for data
        LCD_DATA=0; RW=0; DI=1;
        // clear the row
        for (y=0; y<64; y++)
        {
            _lcd_enable(); 
            //Delay10TCYx(1);
        }
    }
}
void lcd_setpage(unsigned char page)
{
    _lcd_waitbusy();
    DI=0; RW=0; 
    LCD_DATA = 0b10111000 | page;
    _lcd_enable();
}

void lcd_setyaddr(unsigned char y)
{
    _lcd_waitbusy();
    DI=0; RW=0;
    LCD_DATA = 0b01000000 | (y & 0b00111111);
    _lcd_enable();
}
void _lcd_waitbusy(void)
{
    while (_lcd_status() & 0b10000000)
    {
        Delay10TCYx(250); // .5 ms
    }
}
void lcd_write (unsigned char data)
{
    _lcd_waitbusy();
    DI=1; RW=0;
    LCD_TRIS=0; 
    LCD_DATA = data;
    _lcd_enable();
}

void lcd_selectside(unsigned char sides)
{
    // set a CS pin low to enable it
    if (sides & LEFT)
        CS1 = 0;
    else
        CS1 = 1;
    if (sides & RIGHT)
        CS2 = 0;
    else
        CS2 = 1;
}
unsigned char lcd_read (void)
{
    unsigned char _data;
    
    LCD_TRIS=0xFF;
    RW = 1; DI=1;

    _lcd_enable();
    _data = LCD_DATA;
    LCD_TRIS=0x00;
    return _data;
}

void lcd_plotpixel(unsigned char rx, unsigned char ry)
{
    unsigned char data;

    //lcd_waitbusy();

    // select the correct side
    if (rx & 64)
        lcd_selectside(RIGHT);
    else
        lcd_selectside(LEFT);
 
    lcd_setpage( ry >> 3);
    lcd_setyaddr( rx & 0b00111111);
    data = lcd_read(); // dummy read needed here
    data = lcd_read();
    lcd_setyaddr( rx & 0b00111111); 
    lcd_write (data | (1 << (ry & 0b111)));
}
 
void lcd_putchar(char c)
{
    int base;
    base = c - 32;
    base *= 3;

    lcd_write(font[base]);
    lcd_write(font[base + 1]);
    lcd_write(font[base + 2]);
    lcd_write(0);
}
void lcd_putrs(const rom char *string)
{
    char i=0;
    while (string[i] != 0)
        lcd_putchar(string[i++]);
} 

void lcd_puts(char *string)
{
    char i=0;

    while (string[i] != 0)
        lcd_putchar(string[i++]);
} 

Comments:

• SPAMcyberbrain at spamhotmail.com " Thanks a lot for this, I adopted it for Hi-tech C last night, and hopefully I'll try it tonight :)" +

Questions:

• SPAMuwe at spamcme.it asks:

  Dear all,
  
  I've got a simple question: The functin "Delay10TCYx", where is it defined? Is it a 'standard C-function, likt 'printf'... or is it defined in some pic18f.. header file?
  
  Thanks and regards
  
  Uwe

  +
• I have probleme whit :E:\C18\LCD_graph_test\main.c:61:Error [1109] type mismatch in redeclaration of 'lcd_setpage'
  E:\C18\LCD_graph_test\main.c:75:Error [1109] type mismatch in redeclaration of 'lcd_setyaddr'
  Thank's+
• SPAMthemorningstar9 at spamhotmail.com asks: " Error - symbol 'font' has multiple definitions.
  How to fix it?" slippyr4-gmail- replies: did you actually include some font data, in the form requested?+

  +

• SPAMmartinheidelberg at spamyahoo.de asks: " Hi
  
  I try to use the code with a dsPic30F4013.
  The Problem is what does lcd_screenon require as parameter ?
  " slippyr4-gmail- replies: an unsigned char. 1 to turn the screen on, 0 to turn it off.+

  +

• SPAMkarmmi86 at spamgmail.com asks:

  Hi,
  thank you for this piece of code. I'm trying to use it, but I have some difficulities. At beginning of code I set all pins as outputs and then call function lcd_cls(), but then PIC "freezes" :-(. In this function lcd_setpage(x) is ended properly (include _lcd_wait_busy), but in function lcd_setyaddr(0), where _lcd_wait_busy is called again, it freezes in _lcd_wait_busy on that while loop. I have tried increase that time wait before checking status again, but still same problem. I'm using PIC18F452 on 4MHz. Connection of LCD is OK (tested and work well with MikroC development studio). Or have I to call another function before cls? Now my order is:
  lcd_cls();
  lcd_plotpixel (1,1);
  Thank you very much! Michal
  

  +

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