1 | /****************************************************************
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2 | * Einlesen der Tasten einer 3x4 Tastenmatrix *
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3 | * Controller: ATMEL 90PWM316 *
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4 | * Portanschlüsse der Tastenmatrix: *
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5 | * Spalten: row1=PD6, row2=PB2, row3=PB5 *
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6 | * Zeilen: col1=PD5, col2=PD4, col3=PD2, col4=PD1 *
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7 | ****************************************************************/
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8 |
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9 | #include <avr/io.h>
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10 | #include <util/delay.h>
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11 |
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12 | #define NOP(); asm volatile("nop"::);
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13 |
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14 | uint8_t KeyMap[] = // Korrektur der Tastenergebnisse
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15 | { 0, // Anpassung an die Tastatur
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16 | 1, 4, 7, 10, // 1 2 3
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17 | 2, 5, 8, 11, // 4 5 6
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18 | 3, 6, 9, 12 // 7 8 9
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19 | }; // 10 11 12
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20 |
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21 | uint8_t keyscan( void )
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22 | {
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23 | _delay_ms(30);
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24 |
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25 | uint8_t col = 0, row = 0;
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26 |
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27 | //**** Spalten = output + low, Zeilen = input + pull up ****
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28 | DDRB = (1<<PB2)|(1<<PB5);
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29 | DDRD = (1<<PD6);
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30 | PORTB &= ((0<<PB2)|(0<<PB5));
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31 | PORTD &= (0<<PD6);
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32 | PORTD |= (1<<PD1)|(1<<PD2)|(1<<PD4)|(1<<PD5);
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33 |
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34 | NOP(); // wait until inputs sampled
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35 | _delay_us(20);
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36 | if(!(PIND & (1<<PIND5))) // if column 1 = low
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37 | {
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38 | col = 4;
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39 | }
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40 | else if(!(PIND & (1<<PIND4))) // if column 2 = low
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41 | {
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42 | col = 3;
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43 | }
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44 | else if(!(PIND & (1<<PIND2))) // if column 3 = low
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45 | {
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46 | col = 2;
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47 | }
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48 | else if(!(PIND & (1<<PIND1))) // if column 4 = low
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49 | {
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50 | col = 1;
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51 | }
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52 |
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53 | if( col ) // if column found, check row
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54 | {
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55 | //**** Spalten = input + pull up, Zeilen = output + low ****
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56 | DDRB &= ((0<<PB2)|(0<<PB5));
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57 | DDRD &= (0<<PD6);
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58 | PORTB = (1<<PB2)|(1<<PB5);
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59 | PORTD = (1<<PD6);
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60 | DDRD |= (1<<PD1)|(1<<PD2)|(1<<PD4)|(1<<PD5);
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61 | PORTD &= ((0<<PD1)|(0<<PD2)|(0<<PD4)|(0<<PD5));
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62 |
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63 | NOP(); // wait until inputs sampled
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64 | _delay_us(20);
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65 | if(!(PIND & (1<<PIND6))) // if row 1 = low
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66 | {
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67 | row = 5;
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68 | }
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69 | else if(!(PINB & (1<<PINB2))) // if row 2 = low
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70 | {
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71 | row = 9;
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72 | }
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73 | else if(!(PINB & (1<<PINB5))) // if row 3 = low
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74 | {
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75 | row = 13;
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76 | }
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77 | } // 0 = no key
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78 |
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79 | return KeyMap [row - col];
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80 | }
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81 |
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82 | int main (void)
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83 | {
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84 | DDRC = 0xFF;
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85 | while(1)
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86 | {
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87 | PORTC = keyscan();
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88 | }
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89 | }
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