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lcddriver.c
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lcddriver.c
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#include <stdint.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <linux/i2c-dev.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <time.h>
#include "lcddriver.h"
#define LCD_WIDTH (16)
#define LCD_HEIGHT (2)
static void i2c_write_cmd(int fd, uint8_t data)
{
int ret = i2c_smbus_write_byte(fd, data);
if(ret<0) {
printf("i2c_smbus_write_byte failed: %d\n", ret);
}
}
static inline void mysleep(int mili_second)
{
//TODO: change to select
usleep(mili_second*1000);
}
// command
#define LCD_CLEARDISPLAY 0x01
#define LCD_RETURNHOME 0x02
#define LCD_ENTRYMODESET 0x04
#define LCD_DISPLAYCONTROL 0x08
#define LCD_CURSORSHIFT 0x10
#define LCD_FUNCTIONSET 0x20
#define LCD_SETCGRAMADDR 0x40
#define LCD_SETDDRAMADDR 0x80
// flags for display entry mode
#define LCD_ENTRYRIGHT 0x00
#define LCD_ENTRYLEFT 0x02
#define LCD_ENTRYSHIFTINCREMENT 0x01
#define LCD_ENTRYSHIFTDECREMENT 0x00
// flags for display on/off control
#define LCD_DISPLAYON 0x04
#define LCD_DISPLAYOFF 0x00
#define LCD_CURSORON 0x02
#define LCD_CURSOROFF 0x00
#define LCD_BLINKON 0x01
#define LCD_BLINKOFF 0x00
// flags for display/cursor shift
#define LCD_DISPLAYMOVE 0x08
#define LCD_CURSORMOVE 0x00
#define LCD_MOVERIGHT 0x04
#define LCD_MOVELEFT 0x00
// flags for function set
#define LCD_8BITMODE 0x10
#define LCD_4BITMODE 0x00
#define LCD_2LINE 0x08
#define LCD_1LINE 0x00
#define LCD_5x10DOTS 0x04
#define LCD_5x8DOTS 0x00
// flags for backlight control
#define LCD_BACKLIGHT 0x08
#define LCD_NOBACKLIGHT 0x00
#define En 0x04 //0b00000100; // Enable bit
#define Rw 0x02 //0b00000010; // Read/Write bit
#define Rs 0x01 //0b00000001; // Register select bit
static void lcd_strobe(int fd, uint8_t data)
{
i2c_write_cmd(fd, data | En | LCD_BACKLIGHT);
mysleep(1); //.0005);
i2c_write_cmd(fd, ((data & ~En) | LCD_BACKLIGHT));
mysleep(1); //.0001);
}
static void lcd_write_four_bits(int fd, uint8_t data)
{
i2c_write_cmd(fd, data | LCD_BACKLIGHT);
lcd_strobe(fd, data);
}
static void lcd_write(int fd, uint8_t cmd, uint8_t mode /*=0*/)
{
lcd_write_four_bits(fd, mode | (cmd & 0xF0));
lcd_write_four_bits(fd, mode | ((cmd << 4) & 0xF0));
}
void lcd_display_string(int fd, char *str, int line)
{
int i;
if (line == 1) {
lcd_write(fd, 0x80, 0);
}
if (line == 2) {
lcd_write(fd, 0xC0, 0);
}
if (line == 3) {
lcd_write(fd, 0x94, 0);
}
if (line == 4) {
lcd_write(fd, 0xD4, 0);
}
for(i=0; i<LCD_WIDTH /*strlen(str)*/; ++i) {
if(i<strlen(str))
lcd_write(fd, str[i], Rs);
else
lcd_write(fd, ' ', Rs); // fill with blank
}
}
void lcd_clear(int fd)
{
lcd_write(fd, LCD_CLEARDISPLAY, 0);
lcd_write(fd, LCD_RETURNHOME, 0);
}
void lcd_init(int fd)
{
lcd_write(fd, 0x03, 0);
lcd_write(fd, 0x03, 0);
lcd_write(fd, 0x03, 0);
lcd_write(fd, 0x02, 0);
lcd_write(fd, LCD_FUNCTIONSET | LCD_2LINE | LCD_5x8DOTS | LCD_4BITMODE, 0);
// lcd_write(fd, LCD_FUNCTIONSET | LCD_2LINE | LCD_5x8DOTS | LCD_8BITMODE, 0);
lcd_write(fd, LCD_DISPLAYCONTROL | LCD_DISPLAYON, 0);
lcd_write(fd, LCD_CLEARDISPLAY, 0);
lcd_write(fd, LCD_ENTRYMODESET | LCD_ENTRYLEFT, 0);
mysleep(200);
}