Text LCD Library for HD44780

History

What can we say about a standard text LCD? Nothing else then for 90% of your project you usually begin with this LCD. With those friendly functions you will be able to begin your projects without loosing time writing code for the LCD.

Functions Features

	void LCDInit(ushort x,ushort y);
	void LCDOff(void);
	void LCDClrSCR(void);
	void LCDGotoXY(ushort,ushort);
	ushort LCDWhereX(void);
	ushort LCDWhereY(void);
	void LCDWriteString(char *);
	void LCDWriteConstString(const char *);
	void LCDWriteChar(char);
	void LCDWriteData(ushort,ushort);
	ushort LCDReadData(ushort rs);
	void LCDCreateCHR(ushort chnumber, char *ptr);
	void LCDWait(void);
	void LCDDelay50us(int Delay);
	void LCDTextAttr(ushort attribute);
	void LCDContrast(ushort Cont);

Pictures

For those who never saw a Text LCD.....

Sources codes & Schematics


// PC0 -> LCD DB7
// PC1 -> LCD DB6
// PC2 -> LCD DB5
// PC3 -> LCD DB4
// PC4 -> LCD E
// PC5 -> LCD R/W
// PC6 -> LCD RS
// PC7 -> LCD BackLight
//
// PD0 ->
// PD1 ->
// PD2 ->
// PD3 ->
// PD4 ->
// PD5 ->
// PD6 ->
// PD7 -> LCD CONTRAST
//
//*****************************************************************************
//                        T I M E R   U S A G E
//
// Timer 0 not use
// Timer 1 not use
// Timer 2 not use
// Timer 3 not use
//
//*****************************************************************************

//*****************************************************************************
//                            I N C L U D E
//*****************************************************************************
#include <iom32v.h>
#include <shortnametype.h>
#include <macros.h>

//*****************************************************************************
//                            D E F I N E
//*****************************************************************************

// LCD
#define LCD_D7                  0x01
#define LCD_D6                  0x02
#define LCD_D5                  0x04
#define LCD_D4                  0x08
#define LCD_E                   0x10
#define LCD_RW                  0x20
#define LCD_RS                  0x40
#define LCD_BACKLIGHT           0x80

#define LCD_PIN                 PINC
#define LCD_DDR                 DDRC
#define LCD_PORT                PORTC

#define LCD_DATA                0x01
#define LCD_CTRL                0x00

#define LCD_C_BLINK_ON          0x09
#define LCD_C_BLINK_OFF         0xfe
#define LCD_C_ON                0x0a
#define LCD_C_OFF               0xfd
#define LCD_DISPLAY_ON          0x0c
#define LCD_DISPLAY_OFF         0xfb
#define LCD_BRIGHT_25           0x23
#define LCD_BRIGHT_50           0x22
#define LCD_BRIGHT_75           0x21
#define LCD_BRIGHT_100          0x20
#define LCD_BACKLIGHT_ON        0x24
#define LCD_BACKLIGHT_OFF       0x25

//*****************************************************************************
//                            P R O T O T Y P E
//*****************************************************************************
void main(void);

// LCD
void LCDInit(ushort x,ushort y);
void LCDOff(void);
void LCDClrSCR(void);
void LCDGotoXY(ushort,ushort);
ushort LCDWhereX(void);
ushort LCDWhereY(void);
void LCDWriteString(char *);
void LCDWriteConstString(const char *);
void LCDWriteChar(char);
void LCDWriteData(ushort,ushort);
ushort LCDReadData(ushort rs);
void LCDCreateCHR(ushort chnumber, char *ptr);
void LCDWait(void);
void LCDDelay50us(int Delay);
void LCDTextAttr(ushort attribute);
void LCDContrast(ushort Cont);

//*****************************************************************************
//                      G L O B A L   V A R I A B L E
//*****************************************************************************
// LCD
ushort MaxX, MaxY, LCDStat;
char Text[20];


//*****************************************************************************
//                      M A I N
//*****************************************************************************
void main()
{

  SEI(); //re-enable interrupts

  LCDInit(20,2);

  LCDClrSCR();
  LCDGotoXY(1,1);
  LCDWriteConstString("Test Test Test Test\0");
  LCDGotoXY(1,2);
  LCDWriteConstString("--------------------\0");


   while(TRUE)
   {
     WDR();
   }
}

//*****************************************************************************
// LCD Code
//*****************************************************************************
/******************************************************************************

Name:         LCDCreateCHR

Description:  Create a new char in CGRAM

Input:        ushort  : Character number (0-7)
              *ushort : 7 ushort containing the data

Output:       none

Misc:

******************************************************************************/
void LCDCreateCHR(ushort chnumber, char *ptr)
{
  ushort i,j;

  i = 8 * chnumber;

  for (j=0;j<8;j++)
  {
    LCDWriteData(LCD_CTRL,(0x40 | (i + j)));
    LCDWriteData(LCD_DATA,ptr[j]);
  }
}


/******************************************************************************

Name:         void LCDClrSCR(void)

Description:  Clear the LCD

Input:        none

Output:       none

Misc:

******************************************************************************/
void LCDClrSCR(void)
{
  LCDWait();
  LCDWriteData(LCD_CTRL,0x01);      // Clear display
}

/******************************************************************************

Name:         LCDGotoXY(ushort x, ushort y)

Description:  Position cursor on the LCD at X & Y location

Input:        X -> X position on the LCD
              Y -> Y position on the LCD

Output:       none

Misc:

******************************************************************************/
void LCDGotoXY(ushort x,ushort y)
{
  ushort address;

  x--;

  if (MaxY < 3)
  {
    switch(y)
    {
      case '\x01' :
      address = 0 + x;
      break;
      case '\x02' :
      address = 64 + x;
      break;
    }
  }
  else
  {
    switch(y)
    {
      case '\x01' :
      address = 0 + x;
      break;
      case '\x02' :
      address = 64 + x;
      break;
      case '\x03' :
      address = 20 + x;
      break;
      case '\x04' :
      address = 84 + x;
      break;
    }
  }
  LCDWriteData(LCD_CTRL,address | 0x80);
}

/******************************************************************************

Name:         LCDWhereX

Description:  Get the x position of the cursor on the LCD

Input:        None

Output:       ushort : Cursor position "x"

Misc:

******************************************************************************/
ushort LCDWhereX(void)
{
ushort i,x,y;

i = LCDReadData(LCD_CTRL) & 0x7f;

y = LCDWhereY();

if (MaxY == 2)
    {
    if (y == 1) x = i;
    if (y == 2) x = i - 0x40;
    }
else if (MaxY == 4)
    {
    if (y == 1) x = i;
    if (y == 2) x = i - 0x40;
    if (y == 3) x = i - 0x14;
    if (y == 4) x = i - 0x54;
    }
x = x + 1;
return x;
}

/******************************************************************************

Name:         LCDWhereY

Description:  Get the y position of the cursor on the LCD

Input:        None

Output:       ushort : Cursor position "y"

Misc:

******************************************************************************/
ushort LCDWhereY(void)
{
  ushort i,j;

  i = LCDReadData(LCD_CTRL) & 0x7f;

  if (MaxY == 2)
  {
    if (i < 0x28) j = 1;
    else j = 2;
  }
  else if (MaxY == 4)
  {
    if ((i >0x00) && (i < 0x15)) j = 1;
    if ((i >0x14) && (i < 0x28)) j = 3;
    if ((i >0x40) && (i < 0x55)) j = 2;
    if ((i >0x54) && (i < 0x68)) j = 4;
  }
  return j;
}

/******************************************************************************

Name:         WtireByteLCD(char byte)

Description:  Write a byte on the LCD at cursor position

Input:        byte

Output:       none

Misc:

******************************************************************************/
void LCDWriteChar(char byte)
{
  char tmp;

  tmp = byte & 0xf0;
  tmp = tmp >> 4;
  tmp += 0x30;
  if (tmp > 0x39) tmp += 0x07;
  LCDWriteData(LCD_DATA,tmp);

  tmp = byte & 0x0f;
  tmp += 0x30;
  if (tmp > 0x39) tmp += 0x07;
  LCDWriteData(LCD_DATA,tmp);
}

/******************************************************************************

Name:         void LCDWriteString(char *ptr)

Description:  Write a string from RAM on the LCD

Input:        string pointer

Output:       none

Misc:

******************************************************************************/
void LCDWriteString(char *ptr)
{
  ushort i;

  for (i=1;i<41;i++)
  {
    if (*ptr == 0x00) break;
    LCDWriteData(LCD_DATA,*ptr++);
  }
}

/******************************************************************************

Name:         void LCDWriteConstString(const char *ptr)

Description:  Write a constant string on the LCD

Input:        string pointer

Output:       none

Misc:

******************************************************************************/
void LCDWriteConstString(const char *ptr)
{
  ushort i;

  for (i=1;i<41;i++)
  {
    if (*ptr == 0x00) break;
    else if (i == 21) LCDGotoXY(1,2);
    LCDWriteData(LCD_DATA,*ptr++);
  }
}

/******************************************************************************

Name:         void LCDWriteData(ushort rs, ushort ch)

Description:  Write a byte in rs of the LCD

Input:        rs -> Register select
              ch -> byte to write

Output:       none

Misc:

******************************************************************************/
void LCDWriteData(ushort rs,ushort ch)
{
  ushort Stat;

  Stat = LCD_PIN & LCD_BACKLIGHT;

  LCD_PORT = Stat;

  LCDWait();

  if ((ch & 0x80) == 0x80) LCD_PORT |= LCD_D7;
  if ((ch & 0x40) == 0x40) LCD_PORT |= LCD_D6;
  if ((ch & 0x20) == 0x20) LCD_PORT |= LCD_D5;
  if ((ch & 0x10) == 0x10) LCD_PORT |= LCD_D4;
  if (rs == 1) LCD_PORT |= LCD_RS;
  LCDDelay50us(1);

  LCD_PORT |= LCD_E;
  LCD_PORT &= ~LCD_E;

  LCD_PORT = Stat;
  if ((ch & 0x08) == 0x08) LCD_PORT |= LCD_D7;
  if ((ch & 0x04) == 0x04) LCD_PORT |= LCD_D6;
  if ((ch & 0x02) == 0x02) LCD_PORT |= LCD_D5;
  if ((ch & 0x01) == 0x01) LCD_PORT |= LCD_D4;
  if (rs == 1) LCD_PORT |= LCD_RS;
   LCDDelay50us(1);

  LCD_PORT |= LCD_E;
  LCD_PORT &= ~LCD_E;
}

/******************************************************************************

Name:         ushort LCDRead(ushort rs)

Description:  read a byte in rs of the LCD

Input:        rs -> Register select

Output:       ushort

Misc:    

******************************************************************************/
ushort LCDReadData(ushort rs)
{
  ushort Byte=0;

  LCD_DDR &= ~(LCD_D7 + LCD_D6 + LCD_D5 + LCD_D4);

  LCD_PORT = LCD_PIN & LCD_BACKLIGHT;
  LCD_PORT |= LCD_RW;
  if (rs == 1) LCD_PORT |= LCD_RS;
  LCDDelay50us(1);

  LCD_PORT |= LCD_E;
  LCD_PORT |= LCD_E;
  if (LCD_PIN & LCD_D7) Byte |= 0x80;
  if (LCD_PIN & LCD_D6) Byte |= 0x40;
  if (LCD_PIN & LCD_D5) Byte |= 0x20;
  if (LCD_PIN & LCD_D4) Byte |= 0x10;
  LCD_PORT &= ~LCD_E;

   LCD_PORT |= LCD_E;
  LCD_PORT |= LCD_E;
  if (LCD_PIN & LCD_D7) Byte |= 0x08;
  if (LCD_PIN & LCD_D6) Byte |= 0x04;
  if (LCD_PIN & LCD_D5) Byte |= 0x02;
  if (LCD_PIN & LCD_D4) Byte |= 0x01;
  LCD_PORT &= ~LCD_E;

  LCD_PORT &= ~LCD_RW;

  LCD_DDR |= LCD_D7 + LCD_D6 + LCD_D5 + LCD_D4;

  return (Byte);
}

/******************************************************************************

Name:         void LCDWait(void)

Description:  wait for the LCD to be ready

Input:        none

Output:       none

Misc:    

******************************************************************************/
void LCDWait(void)
{
  while((LCDReadData(0) & 0x80) == 0x80) WDR();
}

/******************************************************************************

Name:         void LCDDelay50us(int Delay)

Description:  Delay of 50 us with a 16Mhz resonator

Input:        Delay X x 50us

Output:       none

Misc:

******************************************************************************/
void LCDDelay50us(int Delay)
{
  int i,j;

  for (i=0;i<Delay;i++)
  {
    for (j=1;j<120;j++);
    asm("WDR");
  }
}

/******************************************************************************

Name:         void LCDTextAttr(ushort Attribute)

Description:  Set the LCD attribute

Input:        LCD_C_BLINK_ON     : Cursor blink on
              LCD_C_BLINK_OFF    : Cursor blink off
              LCD_C_ON           : Cursor on
              LCD_C_OFF          : Cursor off
              LCD_DISPLAY_ON     : Display ON
              LCD_DISPLAY_OFF    : Display OFF
              LCD_BRIGHT_25      : VFD 25% Bright
              LCD_BRIGHT_50      : VFD 50% Bright
              LCD_BRIGHT_75      : VFD 75% Bright
              LCD_BRIGHT_100     : VFD 100% Bright
              LCD_BACK_LIGHT_ON  : Back Light ON
              LCD_BACK_LIGHT_OFF : Back Light OFF

Output:       none

Misc:

******************************************************************************/
void LCDTextAttr(ushort attribute)
{
switch (attribute)
    {
    case LCD_C_BLINK_ON:
         LCDStat |= LCD_C_BLINK_ON;
         LCDWriteData(LCD_CTRL,LCDStat);
         break;

    case LCD_C_BLINK_OFF:
         LCDStat &= LCD_C_BLINK_OFF;
         LCDWriteData(LCD_CTRL,LCDStat);
         break;

    case LCD_C_ON:
         LCDStat |= LCD_C_ON;
         LCDWriteData(LCD_CTRL,LCDStat);
         break;

    case LCD_C_OFF:
         LCDStat &= LCD_C_OFF;
         LCDWriteData(LCD_CTRL,LCDStat);
         break;

    case LCD_DISPLAY_ON:
         LCDStat |= LCD_DISPLAY_ON;
         LCDWriteData(LCD_CTRL,LCDStat);
         break;

    case LCD_DISPLAY_OFF:
         LCDStat &= LCD_DISPLAY_OFF;
         LCDWriteData(LCD_CTRL,LCDStat);
         break;

    case LCD_BRIGHT_25:
         LCDWriteData(LCD_CTRL,0x20);
         LCDWriteData(LCD_DATA,0x03);
         break;

    case LCD_BRIGHT_50:
         LCDWriteData(LCD_CTRL,0x20);
         LCDWriteData(LCD_DATA,0x02);
         break;

    case LCD_BRIGHT_75:
         LCDWriteData(LCD_CTRL,0x20);
         LCDWriteData(LCD_DATA,0x01);
         break;

    case LCD_BRIGHT_100:
         LCDWriteData(LCD_CTRL,0x20);
         LCDWriteData(LCD_DATA,0x00);
         break;

    case LCD_BACKLIGHT_ON:
         LCD_PORT |= LCD_BACKLIGHT;
         break;

    case LCD_BACKLIGHT_OFF:
         LCD_PORT &= ~(LCD_BACKLIGHT);
         break;
    }
}

/******************************************************************************

Name:         void LCDOn(ushort X, ushort Y)

Description:  Initialize LCD in 4bit mode

Input:        ushort X -> X size
              ushort Y -> Y size

Output:       none

Misc:

******************************************************************************/
void LCDInit(ushort X, ushort Y)
{
  MaxX = X;
  MaxY = Y;
  LCDStat = 0x0c;
  LCD_PORT = 0x00;
  LCD_DDR = LCD_D7+LCD_D6+LCD_D5+LCD_D4+LCD_E+LCD_RS+LCD_RW+LCD_BACKLIGHT;
  LCD_PORT = ~(LCD_D7+LCD_D6+LCD_D5+LCD_D4+LCD_E+LCD_RS+LCD_RW);
  LCD_PORT |= LCD_BACKLIGHT;
  LCDDelay50us(340);

  LCD_PORT = (LCD_D5 + LCD_D4 + LCD_BACKLIGHT);
  LCD_PORT |= LCD_E;
  LCD_PORT &= ~LCD_E;
  LCDDelay50us(100);
  LCD_PORT |= LCD_E;
  LCD_PORT &= ~LCD_E;
  LCDDelay50us(100);
  LCD_PORT |= LCD_E;
  LCD_PORT &= ~LCD_E;
  LCDDelay50us(100);

  LCD_PORT = (LCD_D5 + LCD_BACKLIGHT);
  LCD_PORT |= LCD_E;
  LCD_PORT &= ~LCD_E;
  LCDDelay50us(100);

  if (Y == 1) LCDWriteData(LCD_CTRL,0x20);    // 1 line
  else LCDWriteData(LCD_CTRL,0x28);           // 2 line

  LCDWriteData(LCD_CTRL,0x0c);                // Disp ON-Cur OFF-Blink OFF
  LCDWriteData(LCD_CTRL,0x01);                // Clear display
  LCDDelay50us(50);
  LCDWriteData(LCD_CTRL,0x06);                // Cursor INC Shift OFF

  DDRD |= 0x80;
  TCCR2 = 0x79;
  OCR2 = 0xff;
}

/******************************************************************************

Name:         void LCDContrast(ushort Cont)

Description:  Set the LCD Contrast

Input:        from 0 to 255

Output:       none

Misc:

******************************************************************************/
void LCDContrast(ushort Cont)
{
  OCR2 = Cont;
}

/******************************************************************************

Name:         void LCDOff(void)

Description:  Shut down LCD

Input:        none

Output:       none

Misc:

******************************************************************************/
void LCDOff(void)
{
 LCD_DDR = 0xff;
 LCD_PORT = 0x00;
 DDRD &= ~0x80;
}