1 | //----------------------------------------
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2 | // Reset DS18S20
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3 | //----------------------------------------
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4 | uint8_t ds1820_reset(uint8_t used_pin)
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5 | {
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6 | uint8_t err=100;
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7 | DS1820_DDR |= 1<<used_pin; // define as ouput
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8 | DS1820_PORT &= ~(1<<used_pin); //Pull low
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9 | _delay_us(480); ; // 480 us
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10 | DS1820_DDR &= ~(1<<used_pin); // define as input
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11 | DS1820_PORT |= 1<<used_pin; //Pullup on
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12 | _delay_us(66); // 66 us
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13 | err = (DS1820_PIN & (1<<used_pin)) >> used_pin; // no presence detect --> err=1 otherwise err=0
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14 | _delay_us(240); // 240 us
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15 | if( (DS1820_PIN & (1<<used_pin)) == 0 ){ // short circuit --> err=2
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16 | err = 2;
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17 | }
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18 | return err;
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19 | }
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20 | //-----------------------------------------
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21 | // Write one bit to DS18S20
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22 | //-----------------------------------------
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23 | void ds1820_wr_bit(uint8_t wrbit,uint8_t used_pin)
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24 | {
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25 | if (wrbit ==0) {
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26 | DS1820_DDR |= 1<<used_pin; // define as ouput
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27 | DS1820_PORT &= ~(1<<used_pin); //Pull low
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28 | _delay_us(60);
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29 | DS1820_DDR &= ~(1<<used_pin); // define as input
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30 | DS1820_PORT |= 1<<used_pin; //Pullup on
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31 | _delay_us(4);
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32 | }
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33 | if (wrbit ==1) {
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34 | DS1820_DDR |= 1<<used_pin; // define as ouput
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35 | DS1820_PORT &= ~(1<<used_pin); //Pull low
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36 | _delay_us(10);
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37 | DS1820_DDR &= ~(1<<used_pin); // define as input
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38 | DS1820_PORT |= 1<<used_pin; //Pullup on
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39 | _delay_us(54);
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40 | }
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41 | }
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42 | //-----------------------------------------
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43 | // Read one bit from DS18S20
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44 | //-----------------------------------------
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45 | uint8_t ds1820_re_bit(uint8_t used_pin)
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46 | {
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47 | uint8_t rebit;
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48 | DS1820_DDR |= 1<<used_pin; // define as ouput
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49 | DS1820_PORT &= ~(1<<used_pin); //Pull low
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50 | _delay_us(1);
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51 | DS1820_DDR &= ~(1<<used_pin); // define as input
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52 | DS1820_PORT |= 1<<used_pin; //Pullup on
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53 | _delay_us(10);
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54 | rebit = (DS1820_PIN & (1<<used_pin)) >> used_pin; //Read bit
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55 | _delay_us(50);
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56 | return rebit;
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57 | }
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58 | //-----------------------------------------
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59 | // Read 1 byte from DS18S20
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60 | //-----------------------------------------
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61 | uint8_t ds1820_re_byte(uint8_t used_pin)
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62 | {
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63 | uint8_t rebyte =0x00;
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64 | uint8_t rebit;
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65 | uint8_t i;
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66 |
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67 | for (i=0;i<8;i++)
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68 | {
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69 | rebit=ds1820_re_bit(used_pin);
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70 | //delay_us(2); //be on the save side
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71 | if (rebit==1){
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72 | rebyte|=(1<<i);
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73 | }
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74 | }
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75 | return(rebyte);
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76 | }
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77 | //-----------------------------------------
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78 | // Write 1 byte to DS18S20
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79 | //-----------------------------------------
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80 | void ds1820_wr_byte(uint8_t wrbyte,uint8_t used_pin)
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81 | {
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82 | uint8_t i;
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83 | for (i=0; i<8; i++) // writes byte, one bit at a time
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84 | {
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85 | ds1820_wr_bit((wrbyte & 0b00000001),used_pin);
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86 | wrbyte = wrbyte >> 1;
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87 | }
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88 | _delay_us(5);
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89 | }
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90 |
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91 |
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92 | void convert(uint8_t used_pin)
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93 | {
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94 |
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95 | uint8_t i = 0;
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96 | uint8_t ow_buffer[10];
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97 | int16_t Vorkommastelle;
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98 |
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99 |
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100 | cli();
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101 |
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102 | ds1820_reset(used_pin); //1. Reset
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103 | ds1820_wr_byte(0xCC,used_pin); //2. skip ROM
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104 | ds1820_wr_byte(0x44,used_pin); //3. ask for temperature conversion
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105 |
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106 | _delay_ms(1000);
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107 |
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108 | ds1820_reset(used_pin); //5. Reset
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109 | ds1820_wr_byte(0xCC,used_pin); //6. skip ROM
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110 | ds1820_wr_byte(0xBE,used_pin); //7. Read entire scratchpad 9 bytes
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111 |
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112 | for (i=0; i<9; i++) //8. Get scratchpad byte by byte
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113 | {
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114 | ow_buffer[i]=ds1820_re_byte(used_pin); //9. read one DS18S20 byte
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115 | }
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116 |
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117 |
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118 | sei();
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119 |
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120 |
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121 | Vorkommastelle = (int16_t)( ( ow_buffer[1] << 8 ) | ow_buffer[0] );
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122 | sprintf( txbuf, "%+03d.%1d", Vorkommastelle/2, ( Vorkommastelle%2) * 5 );
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123 |
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124 | rf12_txdata_TEST(txbuf,22);
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125 | }
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