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LCD 40x4 driver

 
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huichoman



Joined: 20 Nov 2006
Posts: 2

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LCD 40x4 driver
PostPosted: Sun Sep 16, 2007 3:48 pm     Reply with quote

This driver is for use with 40x4 LCDs. It's based in flex_lcd420 by PCM programmer.

Proteus simulation.





driver source code

Code:

//lcd_40x4_h.c by huichoman
//Modificación flex_LCD420.c
//JOSE LUIS SANTIAGO MORALES --Huichoman--
//Tuxtla Gutiérrez, Chiapas, México

// These pins are for my Microchip PicDem2-Plus board,
// which I used to test this driver.
// An external 20x4 LCD is connected to these pins.
// Change these pins to match your own board's connections.

#define LCD_DB4   PIN_B4
#define LCD_DB5   PIN_B5
#define LCD_DB6   PIN_B6
#define LCD_DB7   PIN_B7

#define LCD_RS    PIN_B0
#define LCD_RW    PIN_B1
#define LCD_E1    PIN_B2
#define LCD_E2    PIN_B3
/*
// To prove that the driver can be used with random
// pins, I also tested it with these pins:
#define LCD_DB4   PIN_D4
#define LCD_DB5   PIN_B1
#define LCD_DB6   PIN_C5
#define LCD_DB7   PIN_B5

#define LCD_RS    PIN_E2
#define LCD_RW    PIN_B2
#define LCD_E1     PIN_D6
*/

// If you want only a 6-pin interface to your LCD, then
// connect the R/W pin on the LCD to ground, and comment
// out the following line.  Doing so will save one PIC
// pin, but at the cost of losing the ability to read from
// the LCD.  It also makes the write time a little longer
// because a static delay must be used, instead of polling
// the LCD's busy bit.  Normally a 6-pin interface is only
// used if you are running out of PIC pins, and you need
// to use as few as possible for the LCD.
#define USE_RW_PIN   1     


// These are the line addresses for most 4x20 LCDs.
#define LCD_LINE_1_ADDRESS 0x00
#define LCD_LINE_2_ADDRESS 0x40
#define LCD_LINE_3_ADDRESS 0x00
#define LCD_LINE_4_ADDRESS 0x40

// These are the line addresses for LCD's which use
// the Hitachi HD66712U controller chip.
/*
#define LCD_LINE_1_ADDRESS 0x00
#define LCD_LINE_2_ADDRESS 0x20
#define LCD_LINE_3_ADDRESS 0x40
#define LCD_LINE_4_ADDRESS 0x60
*/


//========================================

#define lcd_type 2   // 0=5x7, 1=5x10, 2=2 lines(or more)

int8 lcd_line;

int8 const LCD_INIT_STRING[4] =
{
 0x20 | (lcd_type << 2),  // Set mode: 4-bit, 2+ lines, 5x8 dots
 0xc,                     // Display on
 1,                       // Clear display
 6                        // Increment cursor
 };
                             
//DISPLAY 1
//-------------------------------------
void lcd_send_nibble1(int8 nibble)
{
// Note:  !! converts an integer expression
// to a boolean (1 or 0).
 output_bit(LCD_DB4, !!(nibble & 1));
 output_bit(LCD_DB5, !!(nibble & 2)); 
 output_bit(LCD_DB6, !!(nibble & 4));   
 output_bit(LCD_DB7, !!(nibble & 8));   

 delay_cycles(1);
 output_high(LCD_E1);
 delay_us(2);
 output_low(LCD_E1);
}

//DISPLAY 2
//-------------------------------------
void lcd_send_nibble2(int8 nibble)
{
// Note:  !! converts an integer expression
// to a boolean (1 or 0).
 output_bit(LCD_DB4, !!(nibble & 1));
 output_bit(LCD_DB5, !!(nibble & 2)); 
 output_bit(LCD_DB6, !!(nibble & 4));   
 output_bit(LCD_DB7, !!(nibble & 8));   

 delay_cycles(1);
 output_high(LCD_E2);
 delay_us(2);
 output_low(LCD_E2);
}


//-----------------------------------
// This sub-routine is only called by lcd_read_byte().
// It's not a stand-alone routine.  For example, the
// R/W signal is set high by lcd_read_byte() before
// this routine is called.     

#ifdef USE_RW_PIN
int8 lcd_read_nibble(void)
{
int8 retval;
// Create bit variables so that we can easily set
// individual bits in the retval variable.
#bit retval_0 = retval.0
#bit retval_1 = retval.1
#bit retval_2 = retval.2
#bit retval_3 = retval.3

retval = 0;
   
output_high(LCD_E1);

delay_us(1);

retval_0 = input(LCD_DB4);
retval_1 = input(LCD_DB5);
retval_2 = input(LCD_DB6);
retval_3 = input(LCD_DB7);
 
output_low(LCD_E1);
delay_us(1);
   
return(retval);   
}   
#endif


//---------------------------------------
// Read a byte from the LCD and return it.

#ifdef USE_RW_PIN
int8 lcd_read_byte(void)
{
int8 low;
int8 high;

output_high(LCD_RW);
delay_cycles(1);

high = lcd_read_nibble();

low = lcd_read_nibble();

return( (high<<4) | low);
}
#endif

//DISPLAY 1
//----------------------------------------
// Send a byte to the LCD.
void lcd_send_byte1(int8 address, int8 n)
{
output_low(LCD_RS);

#ifdef USE_RW_PIN
while(bit_test(lcd_read_byte(),7)) ;
#else
delay_us(60); 
#endif

if(address)
   output_high(LCD_RS);
else
   output_low(LCD_RS);
     
 delay_cycles(1);

#ifdef USE_RW_PIN
output_low(LCD_RW);
delay_cycles(1);
#endif

output_low(LCD_E1);


lcd_send_nibble1(n >> 4);
lcd_send_nibble1(n & 0xf);
}
//----------------------------

//DISPLAY 2
//----------------------------------------
// Send a byte to the LCD.
void lcd_send_byte2(int8 address, int8 n)
{
output_low(LCD_RS);

#ifdef USE_RW_PIN
while(bit_test(lcd_read_byte(),7)) ;
#else
delay_us(60); 
#endif

if(address)
   output_high(LCD_RS);
else
   output_low(LCD_RS);
     
 delay_cycles(1);

#ifdef USE_RW_PIN
output_low(LCD_RW);
delay_cycles(1);
#endif

output_low(LCD_E2);


lcd_send_nibble2(n >> 4);
lcd_send_nibble2(n & 0xf);
}
//----------------------------

//DISPLAY 1
//----------------------------
void lcd_init1(void)
{
int8 i;

lcd_line = 1;

output_low(LCD_RS);

#ifdef USE_RW_PIN
output_low(LCD_RW);
#endif

output_low(LCD_E1);



// Some LCDs require 15 ms minimum delay after
// power-up.  Others require 30 ms.  I'm going
// to set it to 35 ms, so it should work with
// all of them.
delay_ms(35);         

for(i=0 ;i < 3; i++)
   {
    lcd_send_nibble1(0x03);
    delay_ms(5);
   }

lcd_send_nibble1(0x02);

for(i=0; i < sizeof(LCD_INIT_STRING); i++)
   {
    lcd_send_byte1(0, LCD_INIT_STRING[i]);
   
    // If the R/W signal is not used, then
    // the busy bit can't be polled.  One of
    // the init commands takes longer than
    // the hard-coded delay of 50 us, so in
    // that case, lets just do a 5 ms delay
    // after all four of them.
    #ifndef USE_RW_PIN
    delay_ms(5);
    #endif
   }

}

//----------------------------

//DISPLAY 2
//----------------------------
void lcd_init2(void)
{
int8 i;

lcd_line = 1;

output_low(LCD_RS);

#ifdef USE_RW_PIN
output_low(LCD_RW);
#endif

output_low(LCD_E2);


// Some LCDs require 15 ms minimum delay after
// power-up.  Others require 30 ms.  I'm going
// to set it to 35 ms, so it should work with
// all of them.
delay_ms(35);         

for(i=0 ;i < 3; i++)
   {
    lcd_send_nibble2(0x03);
    delay_ms(5);
   }

lcd_send_nibble2(0x02);

for(i=0; i < sizeof(LCD_INIT_STRING); i++)
   {
    lcd_send_byte2(0, LCD_INIT_STRING[i]);
   
    // If the R/W signal is not used, then
    // the busy bit can't be polled.  One of
    // the init commands takes longer than
    // the hard-coded delay of 50 us, so in
    // that case, lets just do a 5 ms delay
    // after all four of them.
    #ifndef USE_RW_PIN
    delay_ms(5);
    #endif
   }

}

//----------------------------



void lcd_gotoxy(int8 x, int8 y)
{
int8 address;


switch(y)
  {
   case 1:
     address = LCD_LINE_1_ADDRESS;
     break;

   case 2:
     address = LCD_LINE_2_ADDRESS;
     break;

   case 3:
     address = LCD_LINE_3_ADDRESS;
     break;

   case 4:
     address = LCD_LINE_4_ADDRESS;
     break;

   default:
     address = LCD_LINE_1_ADDRESS;
     break;
     
  }

address += x-1;
lcd_send_byte1(0, 0x80 | address);
lcd_send_byte2(0, 0x80 | address);
}

// DISPLAY 1
//-----------------------------
void lcd_putc1(char c)
{
 switch(c)
   {
    case '\f':
      lcd_send_byte1(0,1);
      lcd_line = 1;
      delay_ms(2);
      break;
   
    case '\n':
       lcd_gotoxy(1, ++lcd_line);
       break;
   
    case '\b':
       lcd_send_byte1(0,0x10);
       break;
   
    default:
       lcd_send_byte1(1,c);
       break;
   }
}

//------------------------------


//DISPLAY 2
//-----------------------------
void lcd_putc2(char c)
{
 switch(c)
   {
    case '\f':
      lcd_send_byte2(0,1);
      lcd_line = 1;
      delay_ms(2);
      break;
   
    case '\n':
       lcd_gotoxy(1, ++lcd_line);
       break;
   
    case '\b':
       lcd_send_byte2(0,0x10);
       break;
   
    default:
       lcd_send_byte2(1,c);
       break;
   }
}

//------------------------------



#ifdef USE_RW_PIN
char lcd_getc(int8 x, int8 y)
{
char value;

lcd_gotoxy(x,y);

// Wait until busy flag is low.
while(bit_test(lcd_read_byte(),7)); 

output_high(LCD_RS);
value = lcd_read_byte();
output_low(LCD_RS);

return(value);
}
#endif


Test program source code


Code:

//lcd_40x4.c
//Test rutina lcd_40x4_h.c
//Huichoman

#include <18F2525.h>
#use delay(clock=4000000)
#fuses XT, NOPROTECT, PUT, NOWDT, NOBROWNOUT, NOLVP, NOCPD, NOWRT
#include <lcd_40x4_h.c>


void main() {
   lcd_init1();
   delay_ms(2);
   lcd_init2();
   
          while(true) {
           
           
           //TEST 1
           //---------------------------------
           lcd_gotoxy(1,1);
           printf(lcd_putc1,"JOSE LUIS SANTIAGO MORALES");
           delay_ms(1500);
           lcd_gotoxy(1,2);
           printf(lcd_putc1,"HUICHOMAN");
           delay_ms(1500);
           lcd_gotoxy(1,1);
           printf(lcd_putc2,"TEST LCD 40X4");
           delay_ms(1500);
           lcd_gotoxy(1,2);
           printf(lcd_putc2,"PRUEBA SUPERADA");
           delay_ms(1000);
           lcd_putc1("\f");
           delay_ms(1500);
           lcd_putc2("\f");
           delay_ms(1500);
           //---------------------------------
           
           //TEST 1
           //---------------------------------
           lcd_gotoxy(1,1);
           printf(lcd_putc1,"LINEA 1 LCD1");
           delay_ms(1500);
           lcd_gotoxy(1,2);
           printf(lcd_putc1,"LINEA 2 LCD1");
           delay_ms(1500);
           lcd_gotoxy(1,1);
           printf(lcd_putc2,"LINEA 1 LCD2");
           delay_ms(1500);
           lcd_gotoxy(1,2);
           printf(lcd_putc2,"LINEA 2 LCD2");
           delay_ms(1500);
           lcd_gotoxy(1,1);
           printf(lcd_putc1,"LCD 1 LINEA 1");
           delay_ms(1500);
           lcd_gotoxy(1,1);
           printf(lcd_putc2,"LCD 2 LINEA 1");
           delay_ms(1500);
           lcd_gotoxy(1,2);
           printf(lcd_putc1,"LCD 1 LINEA 2");
           delay_ms(1500);
           lcd_gotoxy(1,2);
           printf(lcd_putc2,"LCD 2 LINEA 2");
           delay_ms(1500);
           lcd_putc1("\f");
           delay_ms(1500);
           lcd_putc2("\f");
           //---------------------------------
       
           
            }
   }
 
 

MCDOGANAY



Joined: 09 Apr 2009
Posts: 3
Location: turkey

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LCD 40X4 LINE3 & LINE4 ERROR
PostPosted: Fri Apr 10, 2009 6:37 am     Reply with quote

this driver, line3 and line4 not cursor home. Why ?
khalid_mehmood_attock



Joined: 13 Apr 2010
Posts: 1

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Code 40x4 LCD CODE
PostPosted: Tue Apr 13, 2010 1:27 am     Reply with quote

First Correct these lines
Code:

//TEST 1
           //---------------------------------
           lcd_gotoxy(1,1);
           printf(lcd_putc1,"LINEA 1 LCD1");
           delay_ms(1500);
           lcd_gotoxy(1,2);
           printf(lcd_putc1,"LINEA 2 LCD1");
           delay_ms(1500);
           lcd_gotoxy(1,3);
           printf(lcd_putc2,"LINEA 1 LCD2");
           delay_ms(1500);
           lcd_gotoxy(1,4);
           printf(lcd_putc2,"LINEA 2 LCD2");
           delay_ms(1500);

         //-------------------------

and Change the LCD Module in Proteus

LC4857

It works properly.
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