sad
Dependencies: OneWire
DS1820.cpp@2:b7ad1da7331a, 2015-03-16 (annotated)
- Committer:
- hudakz
- Date:
- Mon Mar 16 08:52:33 2015 +0000
- Revision:
- 2:b7ad1da7331a
- Parent:
- 1:e4689408d617
- Child:
- 3:a250babd0a9f
Bug fix
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
hudakz | 0:433af64321d5 | 1 | #include "DS1820.h" |
hudakz | 0:433af64321d5 | 2 | |
hudakz | 1:e4689408d617 | 3 | #define DEBUG 0 |
hudakz | 0:433af64321d5 | 4 | |
hudakz | 0:433af64321d5 | 5 | #if DEBUG |
hudakz | 0:433af64321d5 | 6 | extern Serial serial; |
hudakz | 0:433af64321d5 | 7 | #endif |
hudakz | 0:433af64321d5 | 8 | |
hudakz | 0:433af64321d5 | 9 | /** |
hudakz | 0:433af64321d5 | 10 | * @brief Constructs a generic DS1820 sensor |
hudakz | 0:433af64321d5 | 11 | * @note begin() must be called to detect and initialize the actual model |
hudakz | 0:433af64321d5 | 12 | * @param Name of data pin |
hudakz | 0:433af64321d5 | 13 | * @retval |
hudakz | 0:433af64321d5 | 14 | */ |
hudakz | 0:433af64321d5 | 15 | DS1820::DS1820(PinName pin) : |
hudakz | 0:433af64321d5 | 16 | oneWire(pin) { |
hudakz | 0:433af64321d5 | 17 | present = 0; |
hudakz | 0:433af64321d5 | 18 | type_s = 0; |
hudakz | 0:433af64321d5 | 19 | } |
hudakz | 0:433af64321d5 | 20 | |
hudakz | 0:433af64321d5 | 21 | /** |
hudakz | 0:433af64321d5 | 22 | * @brief Constructs a specific model |
hudakz | 0:433af64321d5 | 23 | * @note No need to call begin() to detect and initialize the model |
hudakz | 0:433af64321d5 | 24 | * @param One character model name: 'S', 's', 'B' or 'b' |
hudakz | 0:433af64321d5 | 25 | * Name of data pin |
hudakz | 0:433af64321d5 | 26 | * @retval |
hudakz | 0:433af64321d5 | 27 | */ |
hudakz | 0:433af64321d5 | 28 | DS1820::DS1820(char model, PinName pin) : |
hudakz | 0:433af64321d5 | 29 | oneWire(pin) { |
hudakz | 0:433af64321d5 | 30 | if((model == 'S') or (model == 's')) { |
hudakz | 0:433af64321d5 | 31 | present = 1; |
hudakz | 0:433af64321d5 | 32 | type_s = 1; |
hudakz | 0:433af64321d5 | 33 | } |
hudakz | 0:433af64321d5 | 34 | else if((model == 'B') or (model == 'b')) { |
hudakz | 0:433af64321d5 | 35 | present = 1; |
hudakz | 0:433af64321d5 | 36 | type_s = 0; |
hudakz | 0:433af64321d5 | 37 | } |
hudakz | 0:433af64321d5 | 38 | else |
hudakz | 0:433af64321d5 | 39 | present = 0; |
hudakz | 0:433af64321d5 | 40 | } |
hudakz | 0:433af64321d5 | 41 | |
hudakz | 0:433af64321d5 | 42 | /** |
hudakz | 0:433af64321d5 | 43 | * @brief Detects and initializes the actual DS1820 model |
hudakz | 0:433af64321d5 | 44 | * @note |
hudakz | 0:433af64321d5 | 45 | * @param |
hudakz | 0:433af64321d5 | 46 | * @retval true: if a DS1820 family sensor was detected and initialized |
hudakz | 0:433af64321d5 | 47 | false: otherwise |
hudakz | 0:433af64321d5 | 48 | */ |
hudakz | 0:433af64321d5 | 49 | bool DS1820::begin(void) { |
hudakz | 0:433af64321d5 | 50 | oneWire.reset_search(); |
hudakz | 0:433af64321d5 | 51 | wait_ms(250); |
hudakz | 0:433af64321d5 | 52 | if(!oneWire.search(addr)) { |
hudakz | 0:433af64321d5 | 53 | #if DEBUG |
hudakz | 0:433af64321d5 | 54 | serial.printf("No addresses.\r\n"); |
hudakz | 0:433af64321d5 | 55 | #endif |
hudakz | 0:433af64321d5 | 56 | oneWire.reset_search(); |
hudakz | 0:433af64321d5 | 57 | wait_ms(250); |
hudakz | 0:433af64321d5 | 58 | return false; |
hudakz | 0:433af64321d5 | 59 | } |
hudakz | 0:433af64321d5 | 60 | |
hudakz | 0:433af64321d5 | 61 | #if DEBUG |
hudakz | 0:433af64321d5 | 62 | serial.printf("ROM ="); |
hudakz | 0:433af64321d5 | 63 | for(uint8_t i = 0; i < 8; i++) { |
hudakz | 0:433af64321d5 | 64 | serial.printf(" %x", addr[i]); |
hudakz | 0:433af64321d5 | 65 | } |
hudakz | 0:433af64321d5 | 66 | serial.printf("\r\n"); |
hudakz | 0:433af64321d5 | 67 | #endif |
hudakz | 0:433af64321d5 | 68 | |
hudakz | 0:433af64321d5 | 69 | if(OneWire::crc8(addr, 7) == addr[7]) { |
hudakz | 0:433af64321d5 | 70 | present = 1; |
hudakz | 0:433af64321d5 | 71 | |
hudakz | 0:433af64321d5 | 72 | // the first ROM byte indicates which chip |
hudakz | 0:433af64321d5 | 73 | switch(addr[0]) { |
hudakz | 0:433af64321d5 | 74 | case 0x10: |
hudakz | 0:433af64321d5 | 75 | type_s = 1; |
hudakz | 0:433af64321d5 | 76 | #if DEBUG |
hudakz | 0:433af64321d5 | 77 | serial.printf("DS18S20 or old DS1820\r\n"); |
hudakz | 0:433af64321d5 | 78 | #endif |
hudakz | 0:433af64321d5 | 79 | break; |
hudakz | 0:433af64321d5 | 80 | |
hudakz | 0:433af64321d5 | 81 | case 0x28: |
hudakz | 0:433af64321d5 | 82 | type_s = 0; |
hudakz | 0:433af64321d5 | 83 | #if DEBUG |
hudakz | 0:433af64321d5 | 84 | serial.printf("DS18B20\r\n"); |
hudakz | 0:433af64321d5 | 85 | #endif |
hudakz | 0:433af64321d5 | 86 | break; |
hudakz | 0:433af64321d5 | 87 | |
hudakz | 0:433af64321d5 | 88 | case 0x22: |
hudakz | 0:433af64321d5 | 89 | type_s = 0; |
hudakz | 0:433af64321d5 | 90 | #if DEBUG |
hudakz | 0:433af64321d5 | 91 | serial.printf("DS1822\r\n"); |
hudakz | 0:433af64321d5 | 92 | #endif |
hudakz | 0:433af64321d5 | 93 | break; |
hudakz | 0:433af64321d5 | 94 | |
hudakz | 0:433af64321d5 | 95 | default: |
hudakz | 0:433af64321d5 | 96 | present = 0; |
hudakz | 0:433af64321d5 | 97 | #if DEBUG |
hudakz | 0:433af64321d5 | 98 | serial.printf("Device doesn't belong to the DS1820 family\r\n"); |
hudakz | 2:b7ad1da7331a | 99 | #endif |
hudakz | 0:433af64321d5 | 100 | return false; |
hudakz | 0:433af64321d5 | 101 | } |
hudakz | 0:433af64321d5 | 102 | return true; |
hudakz | 0:433af64321d5 | 103 | } |
hudakz | 2:b7ad1da7331a | 104 | else { |
hudakz | 0:433af64321d5 | 105 | #if DEBUG |
hudakz | 0:433af64321d5 | 106 | serial.printf("Invalid CRC!\r\n"); |
hudakz | 2:b7ad1da7331a | 107 | #endif |
hudakz | 0:433af64321d5 | 108 | return false; |
hudakz | 0:433af64321d5 | 109 | } |
hudakz | 0:433af64321d5 | 110 | } |
hudakz | 0:433af64321d5 | 111 | |
hudakz | 0:433af64321d5 | 112 | /** |
hudakz | 0:433af64321d5 | 113 | * @brief Starts temperature conversion |
hudakz | 0:433af64321d5 | 114 | * @note The time to complete the converion depends on the selected resolusion |
hudakz | 0:433af64321d5 | 115 | * @param |
hudakz | 0:433af64321d5 | 116 | * @retval |
hudakz | 0:433af64321d5 | 117 | */ |
hudakz | 0:433af64321d5 | 118 | void DS1820::startConversion(void) { |
hudakz | 0:433af64321d5 | 119 | if(present) { |
hudakz | 0:433af64321d5 | 120 | oneWire.reset(); |
hudakz | 0:433af64321d5 | 121 | |
hudakz | 0:433af64321d5 | 122 | //oneWire.select(addr); |
hudakz | 0:433af64321d5 | 123 | oneWire.skip(); |
hudakz | 0:433af64321d5 | 124 | oneWire.write(0x44); //start conversion |
hudakz | 0:433af64321d5 | 125 | } |
hudakz | 0:433af64321d5 | 126 | } |
hudakz | 0:433af64321d5 | 127 | |
hudakz | 0:433af64321d5 | 128 | /** |
hudakz | 0:433af64321d5 | 129 | * @brief Reads temperature from the chip's scratchpad |
hudakz | 0:433af64321d5 | 130 | * @note |
hudakz | 0:433af64321d5 | 131 | * @param |
hudakz | 0:433af64321d5 | 132 | * @retval Floating point temperature value |
hudakz | 0:433af64321d5 | 133 | */ |
hudakz | 0:433af64321d5 | 134 | float DS1820::read(void) { |
hudakz | 0:433af64321d5 | 135 | if(present) { |
hudakz | 0:433af64321d5 | 136 | oneWire.reset(); |
hudakz | 0:433af64321d5 | 137 | oneWire.skip(); |
hudakz | 0:433af64321d5 | 138 | oneWire.write(0xBE); // to read Scratchpad |
hudakz | 0:433af64321d5 | 139 | for(uint8_t i = 0; i < 9; i++) |
hudakz | 0:433af64321d5 | 140 | data[i] = oneWire.read(); |
hudakz | 0:433af64321d5 | 141 | |
hudakz | 0:433af64321d5 | 142 | // Convert the raw bytes to a 16bit signed fixed point value : |
hudakz | 0:433af64321d5 | 143 | // 1 sign bit, 7 integer bits, 8 fractional bits (two’s compliment |
hudakz | 0:433af64321d5 | 144 | // ie. the LSB of the 16bit binary number represents 1/256th of a unit). |
hudakz | 0:433af64321d5 | 145 | |
hudakz | 0:433af64321d5 | 146 | uint16_t* p_word = reinterpret_cast < uint16_t * > (&data[0]); |
hudakz | 0:433af64321d5 | 147 | |
hudakz | 0:433af64321d5 | 148 | #if DEBUG |
hudakz | 0:433af64321d5 | 149 | serial.printf("raw = %#x\r\n", *p_word); |
hudakz | 0:433af64321d5 | 150 | #endif |
hudakz | 0:433af64321d5 | 151 | |
hudakz | 0:433af64321d5 | 152 | |
hudakz | 0:433af64321d5 | 153 | if(type_s) { |
hudakz | 0:433af64321d5 | 154 | *p_word = *p_word << 3; // default 9 bit resolution |
hudakz | 0:433af64321d5 | 155 | if(data[7] == 0x10) { |
hudakz | 0:433af64321d5 | 156 | |
hudakz | 0:433af64321d5 | 157 | // "count remain" gives full 12 bit resolution |
hudakz | 0:433af64321d5 | 158 | *p_word = (*p_word & 0xFFF0) + 12 - data[6]; |
hudakz | 0:433af64321d5 | 159 | } |
hudakz | 0:433af64321d5 | 160 | |
hudakz | 0:433af64321d5 | 161 | *p_word = *p_word << 4; |
hudakz | 0:433af64321d5 | 162 | return(toFloat(*p_word)); |
hudakz | 0:433af64321d5 | 163 | } |
hudakz | 0:433af64321d5 | 164 | else { |
hudakz | 0:433af64321d5 | 165 | uint8_t cfg = (data[4] & 0x60); |
hudakz | 0:433af64321d5 | 166 | // at lower res, the low bits are undefined, so let's zero them |
hudakz | 0:433af64321d5 | 167 | |
hudakz | 0:433af64321d5 | 168 | if(cfg == 0x00) |
hudakz | 0:433af64321d5 | 169 | *p_word = *p_word &~7; // 9 bit resolution, 93.75 ms |
hudakz | 0:433af64321d5 | 170 | else |
hudakz | 0:433af64321d5 | 171 | if(cfg == 0x20) |
hudakz | 0:433af64321d5 | 172 | *p_word = *p_word &~3; // 10 bit res, 187.5 ms |
hudakz | 0:433af64321d5 | 173 | else |
hudakz | 0:433af64321d5 | 174 | if(cfg == 0x40) |
hudakz | 0:433af64321d5 | 175 | *p_word = *p_word &~1; // 11 bit res, 375 ms |
hudakz | 0:433af64321d5 | 176 | *p_word = *p_word << 4; // default is 12 bit resolution |
hudakz | 0:433af64321d5 | 177 | return(toFloat(*p_word)); |
hudakz | 0:433af64321d5 | 178 | } |
hudakz | 0:433af64321d5 | 179 | } |
hudakz | 0:433af64321d5 | 180 | else |
hudakz | 0:433af64321d5 | 181 | return 0; |
hudakz | 0:433af64321d5 | 182 | } |
hudakz | 0:433af64321d5 | 183 | |
hudakz | 0:433af64321d5 | 184 | /** |
hudakz | 0:433af64321d5 | 185 | * @brief Converts a 16bit signed fixed point value to float |
hudakz | 0:433af64321d5 | 186 | * @note The 16bit unsigned integer represnts actually |
hudakz | 0:433af64321d5 | 187 | * a 16bit signed fixed point value: |
hudakz | 0:433af64321d5 | 188 | * 1 sign bit, 7 integer bits, 8 fractional bits |
hudakz | 0:433af64321d5 | 189 | * (two’s compliment ie. the LSB of the 16bit binary number |
hudakz | 0:433af64321d5 | 190 | * represents 1/256th of a unit). |
hudakz | 0:433af64321d5 | 191 | * @param 16bit unsigned integer |
hudakz | 0:433af64321d5 | 192 | * @retval Floating point temperature value |
hudakz | 0:433af64321d5 | 193 | */ |
hudakz | 0:433af64321d5 | 194 | float DS1820::toFloat(uint16_t word) { |
hudakz | 0:433af64321d5 | 195 | //word = word << 4; |
hudakz | 0:433af64321d5 | 196 | if(word & 0x8000) |
hudakz | 0:433af64321d5 | 197 | return (-float(uint16_t(~word + 1)) / 256.0f); |
hudakz | 0:433af64321d5 | 198 | else |
hudakz | 0:433af64321d5 | 199 | return (float(word) / 256.0f); |
hudakz | 0:433af64321d5 | 200 | } |
hudakz | 0:433af64321d5 | 201 |