HD44780模块LCD接口例程
/***************************************************************************/
/* Lcd.c LCD interface routines */
/* Version : 2.1. for PIC16F87x */
/* J. Winpenny 1/8/2000 */
/* Mode : HD44780 type LCD displays */
/* Notes : Updated version */
/* to allow greater adaptability to different displays */
/***************************************************************************/
#include "lcd873b.h"
/* Definitions for the LCD interface */
#define LCD_SEL 3 /* Port A bit 3 ( Enables LCD ) */
#define LCD_WR 2 /* Port A bit 2 ( Logic 0 = Write ) */
#define LCD_RS 0 /* Port A bit 1 ( Register select ) */
#define LCD_DATA PORTB
#define LCD_CONTROL PORTA
#define BUSY_BIT 7
#define BUSY_MASK 0x80
#define LCD_DATA_4 4 /* LCD BIT 0 */
#define LCD_DATA_5 5 /* LCD BIT 1 */
#define LCD_DATA_6 6 /* LCD BIT 2 */
#define LCD_DATA_7 7 /* LCD BIT 3 */
char ModeFlags;
char LCD_gp;
/***********************************/
/* Setup the lcd device */
/***********************************/
void LCDSetup(void)
{
/* Reset the LCD */
ModeFlags = 0; /* Default to Function Mode */
Write_8_Bit( system_set_4_bit ); /* This sequence resets the LCD */
delay_ms(5);
Write_8_Bit( system_set_4_bit );
delay_ms(1);
Write_8_Bit( system_set_4_bit );
delay_ms(1);
LcdWrite( system_set_4_bit );
LcdWrite( display_on );
LcdWrite( clear_lcd );
LcdWrite( entry_mode );
LcdWrite( set_dd_ram );
ModeFlags = 1; /* Data Mode */
}
/***********************************/
/* Put LCD in Function Mode */
/***********************************/
void FunctionMode(void)
{
BIT_CLEAR( ModeFlags, 0 ); /* Save Mode */
#asm BCF LCD_CONTROL, LCD_RS #endasm
Delaylcd();
}
/***********************************/
/* Put LCD in Data Mode */
/***********************************/
void DataMode(void)
{
BIT_SET( ModeFlags, 0 ); /* Save Mode */
#asm BSF LCD_CONTROL, LCD_RS #endasm
Delaylcd();
}
/***********************************/
/* Write a single byte to the LCD */
/* 8 Bit Mode */
/***********************************/
void Write_8_Bit( char dh )
{
#asm BCF LCD_CONTROL, LCD_WR #endasm
#asm BCF LCD_CONTROL, LCD_RS #endasm
#asm BCF LCD_CONTROL, LCD_SEL #endasm
//LCD_CONTROL = 0;
delay_ms(1);
LCD_DATA = dh; /* Setup data */
BIT_SET( LCD_CONTROL, LCD_SEL ); /* Select LCD */
Delaylcd();
BIT_CLEAR( LCD_CONTROL, LCD_SEL ); /* de-select LCD */
Delaylcd();
}
/***********************************/
/* Write a single byte to the LCD */
/* 4 Bit Mode */
/***********************************/
void LcdWrite(char dl )
{
char e;
e = dl; /* Save lower 4 bits */
/*********************************** Output Upper 8 bits ******************************/
BIT_CLEAR( LCD_CONTROL, LCD_WR ); /* Write mode */
if ( ( ModeFlags & 0x01 ) == 0 )
BIT_CLEAR( LCD_CONTROL, LCD_RS ); /* Function mode */
else
BIT_SET( LCD_CONTROL, LCD_RS ); /* Data mode */
BIT_CLEAR( LCD_CONTROL, LCD_SEL);
LCD_DATA = dl; /* Setup data */
BIT_SET( LCD_CONTROL, LCD_SEL); /* Select LCD */
Delaylcd();
BIT_CLEAR( LCD_CONTROL, LCD_SEL ); /* de-select LCD */
dl = e; /* Restore lower 4 bits */
dl <<= 4;
/*********************************** Output Lower 8 bits ******************************/
BIT_CLEAR( LCD_CONTROL, LCD_WR ); /* Write mode */
if ( ( ModeFlags & 0x01 ) == 0 )
BIT_CLEAR( LCD_CONTROL, LCD_RS ); /* Function mode */
else
BIT_SET( LCD_CONTROL, LCD_RS ); /* Data mode */
BIT_CLEAR( LCD_CONTROL, LCD_SEL);
LCD_DATA = dl; /* Setup data */
BIT_SET( LCD_CONTROL, LCD_SEL); /* Select LCD */
Delaylcd();
BIT_CLEAR( LCD_CONTROL, LCD_SEL ); /* de-select LCD */
Delaylcd();
}
/***********************************/
/* LCD timing delay */
/* Adjust for your LCD Display */
/***********************************/
void Delaylcd(void)
{
delay_ms(2);
}
/***********************************/
/* Clear LCD Screen */
/***********************************/
void Clear(void)
{
FunctionMode();
LcdWrite(clear_lcd);
DataMode();
}
/***********************************/
/* Set the cursor position */
/***********************************/
void SetPos(char Pos)
{
FunctionMode();
LcdWrite( Pos );
DataMode();
}
/***********************************/
/* Set Position to line 1 */
/***********************************/
void Line1(void)
{
FunctionMode();
LcdWrite( set_dd_line1 );
DataMode();
}
/***********************************/
/* Set Position to line 2 */
/***********************************/
void Line2(void)
{
FunctionMode();
LcdWrite( set_dd_line2 );
DataMode();
}
/*******************************************/
/* Clear Line 1 */
/*******************************************/
void ClearLine1(void)
{
Line1();
for( LCD_gp = 0; LCD_gp < 16; LCD_gp++ )
{
LcdWrite(' ');
}
Line1();
}
/*******************************************/
/* Clear Line 2 */
/*******************************************/
void ClearLine2(void)
{
Line2();
for( LCD_gp = 0; LCD_gp < 16; LCD_gp++ )
{
LcdWrite(' ');
}
Line2();
}