1 | /*
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2 | LCD Ausgabe für Hitachi HD44780 kompatible LCD Controller
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3 |
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4 | ATMEGA8/16/32 und kompatibel
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5 |
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6 | Dieses Beispiel sollte mit allen HD44780 kompatiblen LCD
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7 | Displays funktionieren.
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8 | */
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9 |
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10 | #define F_CPU 3686400
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11 |
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12 | #include <avr/io.h>
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13 | #include <util/delay.h>
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14 |
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15 | /*
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16 | * BITTE HIER IHRE VERWENDETEN PINS KONFIGURIEREN!
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17 | *
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18 | * Standardkonfiguration:
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19 | * PORTD7 = LCD D7
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20 | * PORTD6 = LCD D6
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21 | * PORTD5 = LCD D5
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22 | * PORTD4 = LCD D4
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23 | *
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24 | */
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25 | #define LCDPORT PORTD
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26 | #define LCDDDR DDRD
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27 | #define LCD_PIN_RS 2
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28 | #define LCD_PIN_E 3
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29 | #define LCD_PIN_D4 4
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30 | #define LCD_PIN_D5 5
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31 | #define LCD_PIN_D6 6
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32 | #define LCD_PIN_D7 7
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33 |
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34 |
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35 | /* LCD STEUERBEFEHLE ********** */
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36 |
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37 | #define LCD_CLEAR 0x01
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38 | #define LCD_HOME 0x02
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39 | #define LCD_ON 0x0C /* 0x0C = Cursor unsichtbar */
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40 | #define LCD_ON 0x0E /* 0x0E = Cursor sichtbar */
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41 | #define LCD_OFF 0x08
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42 |
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43 | /* HILFSDEFINITIONEN ********** */
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44 |
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45 | #define BEFEHL 0
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46 | #define DATEN 1
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47 | #define sbi(sfr, bit) (sfr|=(1<<bit))
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48 | #define cbi(sfr, bit) (sfr&=~(1<<bit))
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49 |
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50 |
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51 | /****** Schickt ein Byte an den LCD Controller */
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52 | void lcd_send(unsigned char type, unsigned char c)
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53 | {
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54 | if (type==BEFEHL)
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55 | cbi(LCDPORT, LCD_PIN_RS); /* RS=0: Befehl folgt ... */
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56 | else
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57 | sbi(LCDPORT, LCD_PIN_RS); /* RS=1: Daten folgen ... */
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58 |
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59 |
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60 | /* (1) ==== HIGH NIBBLE wird gesendet */
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61 | if (bit_is_set(c, 7)) sbi(LCDPORT, LCD_PIN_D7); else cbi(LCDPORT, LCD_PIN_D7);
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62 | if (bit_is_set(c, 6)) sbi(LCDPORT, LCD_PIN_D6); else cbi(LCDPORT, LCD_PIN_D6);
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63 | if (bit_is_set(c, 5)) sbi(LCDPORT, LCD_PIN_D5); else cbi(LCDPORT, LCD_PIN_D5);
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64 | if (bit_is_set(c, 4)) sbi(LCDPORT, LCD_PIN_D4); else cbi(LCDPORT, LCD_PIN_D4);
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65 |
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66 | /* Flanke zur Übernahme der Daten schicken ... */
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67 | sbi(LCDPORT, LCD_PIN_E);
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68 | cbi(LCDPORT, LCD_PIN_E);
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69 |
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70 |
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71 | /* (2) ==== LOW NIBBLE wird gesendet */
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72 | if (bit_is_set(c, 3)) sbi(LCDPORT, LCD_PIN_D7); else cbi(LCDPORT, LCD_PIN_D7);
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73 | if (bit_is_set(c, 2)) sbi(LCDPORT, LCD_PIN_D6); else cbi(LCDPORT, LCD_PIN_D6);
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74 | if (bit_is_set(c, 1)) sbi(LCDPORT, LCD_PIN_D5); else cbi(LCDPORT, LCD_PIN_D5);
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75 | if (bit_is_set(c, 0)) sbi(LCDPORT, LCD_PIN_D4); else cbi(LCDPORT, LCD_PIN_D4);
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76 |
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77 | /* Flanke zur Übernahme der Daten schicken ... */
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78 | sbi(LCDPORT, LCD_PIN_E);
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79 | cbi(LCDPORT, LCD_PIN_E);
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80 |
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81 |
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82 | /* (3) Auf den LCD Controller warten ...*/
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83 | _delay_ms(5);
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84 | }
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85 |
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86 |
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87 | /****** Stellt eine Zeichenkette am LCD dar */
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88 | void lcd_write(char *t)
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89 | {
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90 | unsigned char i;
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91 | for (i=0;i<255;i++)
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92 | {
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93 | if (t[i]==0) // String-Ende? Dann raus hier ...
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94 | return;
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95 | else
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96 | lcd_send(DATEN, t[i]);
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97 | }
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98 | }
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99 |
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100 |
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101 | /****** Initialisierung des LCD Controllers */
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102 | void lcd_init()
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103 | {
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104 | /* Port auf Ausgang schalten */
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105 | LCDPORT = 0x00;
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106 | LCDDDR = 0xFF;
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107 |
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108 | _delay_ms(50); // Warten bis LCD bereit ...
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109 |
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110 | /* 4-bit Modus konfigurieren */
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111 | sbi(LCDPORT, LCD_PIN_D5);
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112 | cbi(LCDPORT, LCD_PIN_D4);
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113 |
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114 | /* 4-Bit Modus starten ... */
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115 | sbi(PORTD, LCD_PIN_E);
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116 | cbi(PORTD, LCD_PIN_E);
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117 | _delay_ms(5);
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118 |
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119 | /* 2 Zeilen, 4-Bit Modus */
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120 | lcd_send(BEFEHL, 0x28);
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121 |
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122 | lcd_send(BEFEHL, LCD_OFF);
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123 | lcd_send(BEFEHL, LCD_CLEAR);
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124 |
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125 | lcd_send(BEFEHL, 0x06);
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126 | lcd_send(BEFEHL, LCD_ON);
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127 | }
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128 |
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129 |
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130 | /****** Hilfsfunktion: Warte i Sekunden */
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131 | void sekunde(char i)
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132 | {
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133 | unsigned char k;
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134 | for (;i>0;i--)
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135 | {
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136 | for (k=0;k<10;k++)
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137 | _delay_ms(100);
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138 | }
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139 | }
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140 |
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141 |
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142 | /****** HAUPTPROGRAMM *****/
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143 |
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144 | int main(void)
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145 | {
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146 | lcd_init();
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147 | lcd_write("Starting...");
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148 | int i=0;
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149 | while (1)
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150 | {
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151 |
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152 | sekunde(1);
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153 | lcd_send(BEFEHL, LCD_CLEAR);
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154 | if (i==0)
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155 | lcd_write("0");
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156 |
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157 | sekunde(1);
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158 | lcd_send(BEFEHL, LCD_CLEAR);
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159 | lcd_write("1");
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160 | }
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161 | }
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