/*Interfacing Lcd in 4bit mode with LPC2138
By ; Ali Aghayifar
mail : admin@bioemm.com
Code:*/
#include<lpc21xx.h>
#define pin_rs 1<<24 /*lcd rs pin*/
#define pin_rw 1<<23 /*lcd rw pin*/
#define pin_en 1<<22 /*lcd en pin*/
#define pin_ctrl pin_rs|pin_rw|pin_en /*lcd control pins*/
#define lcd_d4 1<<10 /*lcd data pins D4,D5,D6,D7*/
#define lcd_d5 1<<11
#define lcd_d6 1<<12
#define lcd_d7 1<<13
#define lcd_data lcd_d4|lcd_d5|lcd_d6|lcd_d7
#define lcd_rs(x) ((x)?(IOSET1=pin_rs):(IOCLR1=pin_rs)); /*lcd_rs(x) if x=1 will set the lcd_rs pin will clear if x=0*/
#define lcd_rw(x) ((x)?(IOSET1=pin_rw):(IOCLR1=pin_rw));
#define lcd_en(x) ((x)?(IOSET1=pin_en):(IOCLR1=pin_en));
#define data_in ((IOPIN0>>10)&(0x0F)) /*direction of the data pins as input*/
#define data_out(x) IOCLR0=lcd_data; IOSET0=(x & 0x0F)<<10; /*direction of the data pins and control pins
as output*/
#define lcd_all_dir_out IODIR0 |= lcd_data ; IODIR1 |= pin_ctrl; /*setting as output for both data and control pins*/
#define lcd_dir_data_out IODIR0 |= lcd_data
#define lcd_dir_data_in IODIR0 &= ~(lcd_data)
#define delay_2n 4
static void delay(int);
static unsigned char busy_wait();
static void delay(int cnt)
{
cnt <<= delay_2n;
while(cnt--);
}
static unsigned char busy_wait()
{
unsigned char status;
do
{
lcd_dir_data_in;
delay(10);
lcd_rs(0);
delay(10);
lcd_rw(1);
delay(10);
lcd_en(1);
delay(10);
status= (data_in<<4)&(0xF0);
lcd_en(0);
delay(10);
lcd_en(1);
delay(10);
status |=data_in;
lcd_en(0);
delay(10);
lcd_dir_data_out;
delay(10);
}while(status & 0x80);
return (status);
}
void lcd_write_4bit(unsigned char c)
{
lcd_rw(0);
delay(10);
lcd_en(1);
delay(10);
data_out(c & 0x0F);
delay(10);
lcd_en(0);
delay(10);
}
void lcd_cmd_write(unsigned char c)
{
busy_wait();
lcd_rs(0);
delay(10);
lcd_write_4bit(c>>4);
lcd_write_4bit(c);
}
static void lcd_data_write(unsigned char c)
{
busy_wait();
lcd_rs(1);
delay(10);
lcd_write_4bit(c>>4);
lcd_write_4bit(c);
}
void lcd_putchar(char c)
{
lcd_data_write(c);
}
void lcd_init()
{
lcd_all_dir_out;
delay(10);
lcd_rs(0);
lcd_write_4bit(0x3);
delay(10);
lcd_write_4bit(0x3);
delay(10);
lcd_write_4bit(0x3);
lcd_write_4bit(0x2);
lcd_cmd_write(0x28);
lcd_cmd_write(0x0C);
lcd_cmd_write(0x06);
}
int lcd_gotoxy( unsigned int x, unsigned int y)
{
int retval = 0;
if( (x > 1) && (y > 15) )
{
retval = -1;
} else {
if( x == 0 )
{
lcd_cmd_write( 0x80 + y ); /* command - position cursor at 0x00 (0x80 + 0x00 ) */
} else if( x==1 ){
lcd_cmd_write( 0xC0 + y ); /* command - position cursor at 0x40 (0x80 + 0x00 ) */
}
}
return retval;
}
void lcd_clear()
{
lcd_cmd_write(0x01);
lcd_gotoxy(0,0);
}
void lcd_print(unsigned char const *str)
{
while(*str)
{
lcd_putchar(*str++);
}
}
دیدگاه