1 | #include "io430.h"
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2 | #include "intrinsics.h"
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3 |
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4 | // target: MSP430G2553 (Launch Pad)
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5 | //------------------------------------------------------------------------
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6 |
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7 | /* ------------------------------------------------------------------------------------------------
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8 | * Types
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9 | * ------------------------------------------------------------------------------------------------
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10 | */
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11 |
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12 | typedef signed int int8;
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13 | typedef unsigned int uint8;
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14 |
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15 | typedef signed short int16;
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16 | typedef unsigned short uint16;
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17 |
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18 | typedef signed long int32;
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19 | typedef unsigned long uint32;
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20 |
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21 | //----------------------------------------------------------------------------------------------
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22 |
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23 | #define PHASE_A (P1IN & BIT4) // P1.4 als Eingang Encoder
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24 | #define PHASE_B (P1IN & BIT5) // P1.5 als Eingang Encoder
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25 |
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26 |
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27 | volatile int8 enc_delta; // -128 ... 127
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28 | static int8 last;
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29 |
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30 |
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31 | void encode_init( void )
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32 | {
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33 | int8 new;
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34 |
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35 | new = 0;
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36 | if( PHASE_A )
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37 | new = 3;
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38 | if( PHASE_B )
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39 | new ^= 1; // convert gray to binary
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40 | last = new; // power on state
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41 | enc_delta = 0;
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42 | }
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43 |
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44 |
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45 | #pragma vector=TIMER0_A0_VECTOR // 1ms for manual movement
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46 | __interrupt void Timer_A (void)
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47 | {
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48 | int8 new, diff;
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49 |
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50 | new = 0;
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51 | if( PHASE_A )
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52 | new = 3;
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53 | if( PHASE_B )
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54 | new ^= 1; // convert gray to binary
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55 | diff = last - new; // difference last - new
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56 | if( diff & 1 ){ // bit 0 = value (1)
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57 | last = new; // store new as next last
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58 | enc_delta += (diff & 2) - 1; // bit 1 = direction (+/-)
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59 | }
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60 | CCR0 += 2000; // Add Offset to CCR0
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61 | }
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62 |
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63 |
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64 | int8 encode_read1( void ) // read single step encoders
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65 | {
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66 | int8 val;
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67 |
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68 | __disable_interrupt();
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69 | val = enc_delta;
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70 | enc_delta = 0;
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71 | __enable_interrupt();
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72 | return val; // counts since last call
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73 | }
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74 |
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75 |
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76 | int main( void )
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77 | {
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78 | WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer to prevent time out reset
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79 |
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80 | BCSCTL1 = CALBC1_1MHZ; // 1 MHz clock
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81 | DCOCTL = CALDCO_1MHZ;
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82 |
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83 | CCTL0 = CCIE; // CCR0 interrupt enabled
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84 | CCR0 = 2000;
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85 | TACTL = TASSEL_2 + MC_2; // SMCLK, contmode
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86 |
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87 | P1SEL = 0x00; // Port 1 als GPIO nutzen
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88 | P1REN |= (BIT4 + BIT5); // P1.4 und P1.5 Resistor enabled
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89 | P1OUT |= (BIT4 + BIT5); // P1.4 und P1.5 Pullup enabled
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90 | P1DIR |= (BIT0 + BIT6); // P1.0 und P1.6 LEDs
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91 |
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92 |
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93 | int32 val = 0;
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94 |
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95 | encode_init();
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96 | __enable_interrupt();
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97 |
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98 | for(;;)
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99 | {
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100 | val += encode_read1();
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101 |
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102 | if(val > 0)
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103 | P1OUT |= 0x01;
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104 | else
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105 | P1OUT &= ~ 0x01;
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106 |
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107 | if(val < 0)
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108 | P1OUT |= 0x40;
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109 | else
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110 | P1OUT &= ~ 0x40;
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111 | }
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112 | }
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