lcd.c

   1 #include "brmpuk.h"
   2
   3 #include <string.h>
   4 #include <avr/io.h>
   5 #include <util/delay.h>
   6 #include "lcd.h"
   7
   8 static void lcd_putdata(unsigned char data4)
   9 {
  10         PORTG &= ~0x7;
  11         PORTG |= data4 & 0x7;
  12
  13         /* EN pulse: */
  14         PORTD &= ~_BV(PD7);
  15         _delay_us(1);
  16         PORTD |= _BV(PD7);
  17         _delay_us(1);
  18 }
  19
  20 static void lcd_command(unsigned char data8)
  21 {
  22         PORTG &= ~_BV(PG4); // RS low
  23         lcd_putdata(data8 >> 8);
  24         lcd_putdata(data8);
  25 }
  26
  27 static void lcd_data(unsigned char data8)
  28 {
  29         PORTG |= _BV(PG4); // RS high
  30         lcd_putdata(data8 >> 8);
  31         lcd_putdata(data8);
  32 }
  33
  34 static void lcd_clear(void)
  35 {
  36         lcd_command(0x01 /* CLEARDISPLAY */);
  37         _delay_us(2000);
  38 }
  39
  40 void lcd_init(void)
  41 {
  42         DDRD |= _BV(PD7); // EN pin
  43         DDRG |= _BV(PG4); // RS pin
  44         DDRG |= (_BV(PG0)|_BV(PG1)|_BV(PG2)|_BV(PG3)); // data pins
  45         _delay_us(40000);
  46
  47         /* Pull RS, EN low to start talking. */
  48         PORTG &= ~_BV(PG4); // XXX: try pull high?
  49         PORTD &= ~_BV(PD7);
  50         _delay_us(4500); // XXX: needed?
  51
  52         /* Set 4-bit mode. */
  53         lcd_putdata(0x3);
  54         _delay_us(4500);
  55         lcd_putdata(0x3);
  56         _delay_us(4500);
  57         lcd_putdata(0x3);
  58         _delay_us(150);
  59
  60         lcd_command(0x20 /* FUNCTIONCONTROL */ | 0x08 /* 2LINE */);
  61         lcd_command(0x08 /* DISPLAYCONTROL */ | 0x04 /* DISPLAYON */);
  62         lcd_clear();
  63         lcd_command(0x04 /* ENTRYMORE */ | 0x02 /* LTR */);
  64 }
  65
  66 void lcd_text(char *str)
  67 {
  68         lcd_clear();
  69         int i;
  70         for (i = 0; i < strlen(str); i++) {
  71                 lcd_data(str[i]);
  72         }
  73 }