htu21d_for_weather_shield
Dependents: SPARKFUN_WEATHER_SHIELD
Fork of htu21d by
htu21d.h@1:d3ed713f8354, 2014-05-15 (annotated)
- Committer:
- loopsva
- Date:
- Thu May 15 19:12:11 2014 +0000
- Revision:
- 1:d3ed713f8354
- Parent:
- 0:2dab43acb3a4
- Child:
- 3:5c0f8e91d319
Added serial number access structure. Cleaned up documentation.
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
loopsva | 0:2dab43acb3a4 | 1 | /** |
loopsva | 1:d3ed713f8354 | 2 | HTU21D / HPP828E031 driver for mbed. |
loopsva | 1:d3ed713f8354 | 3 | - Includes RTOS hooks if RTOS is detected during compile. |
loopsva | 1:d3ed713f8354 | 4 | Author: Kevin Braun |
loopsva | 1:d3ed713f8354 | 5 | **/ |
loopsva | 0:2dab43acb3a4 | 6 | |
loopsva | 0:2dab43acb3a4 | 7 | #ifndef HTU21D_H |
loopsva | 0:2dab43acb3a4 | 8 | #define HTU21D_H |
loopsva | 0:2dab43acb3a4 | 9 | |
loopsva | 0:2dab43acb3a4 | 10 | #include "mbed.h" |
loopsva | 0:2dab43acb3a4 | 11 | |
loopsva | 0:2dab43acb3a4 | 12 | //Defines for HTU21D |
loopsva | 0:2dab43acb3a4 | 13 | #define HTU21Di2cWRITE 0x80 |
loopsva | 0:2dab43acb3a4 | 14 | #define HTU21Di2cREAD 0x81 |
loopsva | 0:2dab43acb3a4 | 15 | |
loopsva | 0:2dab43acb3a4 | 16 | #define HTU21DWRITEUSER 0xE6 |
loopsva | 0:2dab43acb3a4 | 17 | #define HTU21DREADUSER 0xE7 |
loopsva | 0:2dab43acb3a4 | 18 | #define HTU21DtempNOHOLD 0xF3 |
loopsva | 0:2dab43acb3a4 | 19 | #define HTU21DhumNOHOLD 0xF5 |
loopsva | 0:2dab43acb3a4 | 20 | #define HTU21DRESET 0xFE |
loopsva | 0:2dab43acb3a4 | 21 | |
loopsva | 1:d3ed713f8354 | 22 | #define HTU21SNAC1 0xFC |
loopsva | 1:d3ed713f8354 | 23 | #define HTU21SNAC2 0xC9 |
loopsva | 1:d3ed713f8354 | 24 | #define HTU21SNB1 0xFA |
loopsva | 1:d3ed713f8354 | 25 | #define HTU21SNB2 0x0F |
loopsva | 1:d3ed713f8354 | 26 | |
loopsva | 0:2dab43acb3a4 | 27 | #define HTU21DHEATER 0x04 |
loopsva | 0:2dab43acb3a4 | 28 | |
loopsva | 0:2dab43acb3a4 | 29 | |
loopsva | 1:d3ed713f8354 | 30 | /** |
loopsva | 1:d3ed713f8354 | 31 | * measurement specialties / Honeywell HTU21D digital humidity and temperature sensor. |
loopsva | 1:d3ed713f8354 | 32 | * - Web site: http://www.meas-spec.com |
loopsva | 1:d3ed713f8354 | 33 | * - Part Number: HPP828E031 |
loopsva | 1:d3ed713f8354 | 34 | * - HTU21D = +-3% rh error at 55% |
loopsva | 1:d3ed713f8354 | 35 | * - HTU20D = +-5% rh error at 55% |
loopsva | 1:d3ed713f8354 | 36 | * - Main code generated from datasheet dated October 2013 |
loopsva | 1:d3ed713f8354 | 37 | * - Serial number code generated from App Note "HTU2X Serial Number Reading", dated Februrary 2014 |
loopsva | 1:d3ed713f8354 | 38 | * - No checksum checking is performed in this code |
loopsva | 1:d3ed713f8354 | 39 | * |
loopsva | 1:d3ed713f8354 | 40 | * @code |
loopsva | 1:d3ed713f8354 | 41 | * //Tested on FRDM-K64F |
loopsva | 1:d3ed713f8354 | 42 | * |
loopsva | 1:d3ed713f8354 | 43 | * #include "mbed.h" |
loopsva | 1:d3ed713f8354 | 44 | * #include "htu21d.h" |
loopsva | 1:d3ed713f8354 | 45 | * |
loopsva | 1:d3ed713f8354 | 46 | * #define SDA PTE25 |
loopsva | 1:d3ed713f8354 | 47 | * #define SCL PTE24 |
loopsva | 1:d3ed713f8354 | 48 | * |
loopsva | 1:d3ed713f8354 | 49 | * Serial pc(USBTX, USBRX); //local terminal |
loopsva | 1:d3ed713f8354 | 50 | * htu21d htu(SDA, SCL); //Temp Hum || sda, scl |
loopsva | 1:d3ed713f8354 | 51 | * |
loopsva | 1:d3ed713f8354 | 52 | * float H21Temp = 0.0; //Temperture from HTU21D |
loopsva | 1:d3ed713f8354 | 53 | * float H21Hum = 0.0; //Humidity from HTU21D |
loopsva | 1:d3ed713f8354 | 54 | * float H21Dew = 0.0; //Dew Point from HTU21D |
loopsva | 1:d3ed713f8354 | 55 | * |
loopsva | 1:d3ed713f8354 | 56 | * //Note: If RTOS is used, Mutex for I2C must be initialized |
loopsva | 1:d3ed713f8354 | 57 | * #ifdef RTOS_H |
loopsva | 1:d3ed713f8354 | 58 | * Mutex MutexI2cWait; |
loopsva | 1:d3ed713f8354 | 59 | * #endif |
loopsva | 1:d3ed713f8354 | 60 | * |
loopsva | 1:d3ed713f8354 | 61 | * int main() { |
loopsva | 1:d3ed713f8354 | 62 | * pc.baud(230400); //local terminal baud |
loopsva | 1:d3ed713f8354 | 63 | * pc.printf("\r\n\r\nK64F_HTU21D basic operation\r\n"); |
loopsva | 1:d3ed713f8354 | 64 | * |
loopsva | 1:d3ed713f8354 | 65 | * //initialize the HTU21D |
loopsva | 1:d3ed713f8354 | 66 | * int htu21 = htu.softReset(); |
loopsva | 1:d3ed713f8354 | 67 | * if(htu21 == 0) { |
loopsva | 1:d3ed713f8354 | 68 | * pc.printf(" - HTU21D broken...\r\n"); |
loopsva | 1:d3ed713f8354 | 69 | * } else { |
loopsva | 1:d3ed713f8354 | 70 | * uint8_t HTU21DuserReg = htu.getUserReg(); |
loopsva | 1:d3ed713f8354 | 71 | * pc.printf("HTU21D UserReg: 0x%02x SN: 0x%04x %08x %04x\r\n", |
loopsva | 1:d3ed713f8354 | 72 | * HTU21DuserReg, htu.HTU21sn.HTU21D_sna, htu.HTU21sn.HTU21D_snb, htu.HTU21sn.HTU21D_snc); |
loopsva | 1:d3ed713f8354 | 73 | * } |
loopsva | 1:d3ed713f8354 | 74 | * |
loopsva | 1:d3ed713f8354 | 75 | * while(true) { |
loopsva | 1:d3ed713f8354 | 76 | * //get humidity, temperature and dew point from HTU21D |
loopsva | 1:d3ed713f8354 | 77 | * if(htu21 == 1) { //if HTU21D didn't initialize, don't access HTU21D anymore |
loopsva | 1:d3ed713f8354 | 78 | * H21Hum = htu.getHum(); |
loopsva | 1:d3ed713f8354 | 79 | * if((double)H21Hum == 255.0) pc.printf("\r\n*** HTU21D Hum error!!\r\n"); |
loopsva | 1:d3ed713f8354 | 80 | * H21Temp = htu.getTemp(); |
loopsva | 1:d3ed713f8354 | 81 | * if((double)H21Temp == 255.0) pc.printf("\r\n*** HTU21D Temp error!!\r\n"); |
loopsva | 1:d3ed713f8354 | 82 | * H21Dew = htu.getDewPtFast(); |
loopsva | 1:d3ed713f8354 | 83 | * } |
loopsva | 1:d3ed713f8354 | 84 | * pc.printf("Temp: %7.2f C %7.2f F Hum: %4.1f %% DewPt: %7.2f C\r\n", H21Temp, H21Hum, H21Dew); |
loopsva | 1:d3ed713f8354 | 85 | * wait(1.0); |
loopsva | 1:d3ed713f8354 | 86 | * } |
loopsva | 1:d3ed713f8354 | 87 | * } |
loopsva | 1:d3ed713f8354 | 88 | * @endcode |
loopsva | 1:d3ed713f8354 | 89 | **/ |
loopsva | 0:2dab43acb3a4 | 90 | class htu21d { |
loopsva | 0:2dab43acb3a4 | 91 | |
loopsva | 0:2dab43acb3a4 | 92 | public: |
loopsva | 0:2dab43acb3a4 | 93 | /** |
loopsva | 1:d3ed713f8354 | 94 | * Constructor |
loopsva | 1:d3ed713f8354 | 95 | * - Fixed at I2C address 0x80 |
loopsva | 1:d3ed713f8354 | 96 | * - I2C speed set to 400000 |
loopsva | 0:2dab43acb3a4 | 97 | * |
loopsva | 1:d3ed713f8354 | 98 | * @param PinName sda and scl, mbed I2C interface pins |
loopsva | 0:2dab43acb3a4 | 99 | */ |
loopsva | 0:2dab43acb3a4 | 100 | htu21d(PinName sda, PinName scl); |
loopsva | 0:2dab43acb3a4 | 101 | /** |
loopsva | 1:d3ed713f8354 | 102 | * Constructor |
loopsva | 1:d3ed713f8354 | 103 | * - Fixed at I2C address 0x80 |
loopsva | 1:d3ed713f8354 | 104 | * - I2C speed set by user |
loopsva | 0:2dab43acb3a4 | 105 | * |
loopsva | 1:d3ed713f8354 | 106 | * @param PinName sda and scl, mbed I2C interface pins |
loopsva | 1:d3ed713f8354 | 107 | * @param int I2C frequency |
loopsva | 1:d3ed713f8354 | 108 | */ |
loopsva | 1:d3ed713f8354 | 109 | htu21d(PinName sda, PinName scl, int i2cFrequency); |
loopsva | 1:d3ed713f8354 | 110 | /** |
loopsva | 1:d3ed713f8354 | 111 | * Destructor |
loopsva | 1:d3ed713f8354 | 112 | * |
loopsva | 1:d3ed713f8354 | 113 | * @param --none-- |
loopsva | 0:2dab43acb3a4 | 114 | */ |
loopsva | 0:2dab43acb3a4 | 115 | ~htu21d(); |
loopsva | 0:2dab43acb3a4 | 116 | /** |
loopsva | 1:d3ed713f8354 | 117 | * Reset the HTU21D chip |
loopsva | 1:d3ed713f8354 | 118 | * - Waits 15mS before exiting, allowing the chip reset to finish |
loopsva | 1:d3ed713f8354 | 119 | * - Executes getSNReg() which loads up HTU21D serial number structure |
loopsva | 0:2dab43acb3a4 | 120 | * |
loopsva | 1:d3ed713f8354 | 121 | * @param --none-- NOTE: run softReset() once at initialization time |
loopsva | 0:2dab43acb3a4 | 122 | * |
loopsva | 1:d3ed713f8354 | 123 | * @return success / failure of HTU21D i2c access. 1 = ok, 0 = error |
loopsva | 0:2dab43acb3a4 | 124 | */ |
loopsva | 0:2dab43acb3a4 | 125 | int softReset(); |
loopsva | 0:2dab43acb3a4 | 126 | /** |
loopsva | 1:d3ed713f8354 | 127 | * Get HTU21D user register |
loopsva | 0:2dab43acb3a4 | 128 | * |
loopsva | 1:d3ed713f8354 | 129 | * @param --none-- |
loopsva | 0:2dab43acb3a4 | 130 | * |
loopsva | 1:d3ed713f8354 | 131 | * @return 8 bit user register value |
loopsva | 0:2dab43acb3a4 | 132 | */ |
loopsva | 0:2dab43acb3a4 | 133 | uint8_t getUserReg(); |
loopsva | 0:2dab43acb3a4 | 134 | /** |
loopsva | 1:d3ed713f8354 | 135 | * Turn ON the heater on the HTU21D |
loopsva | 0:2dab43acb3a4 | 136 | * |
loopsva | 1:d3ed713f8354 | 137 | * @param --none-- |
loopsva | 0:2dab43acb3a4 | 138 | * |
loopsva | 1:d3ed713f8354 | 139 | * @return success / failure of HTU21D i2c access. 1 = ok, 0 = error |
loopsva | 0:2dab43acb3a4 | 140 | */ |
loopsva | 0:2dab43acb3a4 | 141 | int heaterOn(); |
loopsva | 0:2dab43acb3a4 | 142 | /** |
loopsva | 1:d3ed713f8354 | 143 | * Turn OFF the heater on the HTU21D |
loopsva | 0:2dab43acb3a4 | 144 | * |
loopsva | 1:d3ed713f8354 | 145 | * @param --none-- |
loopsva | 0:2dab43acb3a4 | 146 | * |
loopsva | 1:d3ed713f8354 | 147 | * @return success / failure of HTU21D i2c access. 1 = ok, 0 = error |
loopsva | 0:2dab43acb3a4 | 148 | */ |
loopsva | 0:2dab43acb3a4 | 149 | int heaterOff(); |
loopsva | 0:2dab43acb3a4 | 150 | /** |
loopsva | 1:d3ed713f8354 | 151 | * Get heater on/off status of the HTU21D |
loopsva | 0:2dab43acb3a4 | 152 | * |
loopsva | 1:d3ed713f8354 | 153 | * @param --none-- |
loopsva | 0:2dab43acb3a4 | 154 | * |
loopsva | 1:d3ed713f8354 | 155 | * @return 0x04 = on, 0 = off |
loopsva | 0:2dab43acb3a4 | 156 | */ |
loopsva | 0:2dab43acb3a4 | 157 | uint8_t getHeater(); |
loopsva | 0:2dab43acb3a4 | 158 | /** |
loopsva | 1:d3ed713f8354 | 159 | * Get HTU21D Temperature |
loopsva | 0:2dab43acb3a4 | 160 | * |
loopsva | 1:d3ed713f8354 | 161 | * @param --none-- |
loopsva | 0:2dab43acb3a4 | 162 | * |
loopsva | 1:d3ed713f8354 | 163 | * @return float of Temperature in degrees C. 255.0 if error |
loopsva | 0:2dab43acb3a4 | 164 | */ |
loopsva | 0:2dab43acb3a4 | 165 | float getTemp(); |
loopsva | 0:2dab43acb3a4 | 166 | /** |
loopsva | 1:d3ed713f8354 | 167 | * Get HTU21D Humidity |
loopsva | 0:2dab43acb3a4 | 168 | * |
loopsva | 1:d3ed713f8354 | 169 | * @param --none-- |
loopsva | 0:2dab43acb3a4 | 170 | * |
loopsva | 1:d3ed713f8354 | 171 | * @return float of Humidity in percentage. 255.0 if error |
loopsva | 0:2dab43acb3a4 | 172 | */ |
loopsva | 0:2dab43acb3a4 | 173 | float getHum(); |
loopsva | 0:2dab43acb3a4 | 174 | /** |
loopsva | 1:d3ed713f8354 | 175 | * Calculate the Dew Point |
loopsva | 0:2dab43acb3a4 | 176 | * |
loopsva | 1:d3ed713f8354 | 177 | * @param --none-- NOTE: You MUST run getTemp() and getHum() first!! |
loopsva | 0:2dab43acb3a4 | 178 | * |
loopsva | 1:d3ed713f8354 | 179 | * @return float of Dew Point |
loopsva | 0:2dab43acb3a4 | 180 | */ |
loopsva | 0:2dab43acb3a4 | 181 | float getDewPt(); |
loopsva | 0:2dab43acb3a4 | 182 | /** |
loopsva | 1:d3ed713f8354 | 183 | * Calculate the Dew Point fast |
loopsva | 1:d3ed713f8354 | 184 | * - 5x faster than getDewPt() |
loopsva | 1:d3ed713f8354 | 185 | * - slightly less accurate than getDewPt() |
loopsva | 0:2dab43acb3a4 | 186 | * |
loopsva | 1:d3ed713f8354 | 187 | * @param --none-- NOTE: You MUST run getTemp() and getHum() first!! |
loopsva | 0:2dab43acb3a4 | 188 | * |
loopsva | 1:d3ed713f8354 | 189 | * @return float of Dew Point |
loopsva | 0:2dab43acb3a4 | 190 | */ |
loopsva | 0:2dab43acb3a4 | 191 | float getDewPtFast(); |
loopsva | 1:d3ed713f8354 | 192 | /** |
loopsva | 1:d3ed713f8354 | 193 | * Structure to access HTU21D's serial number |
loopsva | 1:d3ed713f8354 | 194 | * - HTU21D_sna is the hi 16 bit word of the s/n, always is 0x4854 |
loopsva | 1:d3ed713f8354 | 195 | * - HTU21D_snb is the mid 32 bit word of the s/n, 0x00-------- |
loopsva | 1:d3ed713f8354 | 196 | * - HTU21D_snc is the low 16 bit word of the s/n, 0x32-- |
loopsva | 1:d3ed713f8354 | 197 | * - The complete 64 bit s/n value is: 0x48 54 00 -- -- -- 32 -- |
loopsva | 1:d3ed713f8354 | 198 | * - The numbers shown are fixed fields |
loopsva | 1:d3ed713f8354 | 199 | * - The '-' numbers are variable |
loopsva | 1:d3ed713f8354 | 200 | * - For reference, the CRC values for the s/n are included |
loopsva | 1:d3ed713f8354 | 201 | */ |
loopsva | 1:d3ed713f8354 | 202 | struct HTU21snStruct { |
loopsva | 1:d3ed713f8354 | 203 | uint16_t HTU21D_sna; /**< Highest order 16 bit word of SN |
loopsva | 1:d3ed713f8354 | 204 | - Value always = 0x4854 |
loopsva | 1:d3ed713f8354 | 205 | */ |
loopsva | 1:d3ed713f8354 | 206 | uint32_t HTU21D_snb; /**< Middle order 32 bit word of SN |
loopsva | 1:d3ed713f8354 | 207 | - Value = 0x00-------- |
loopsva | 1:d3ed713f8354 | 208 | - Highest byte always = 0x00 |
loopsva | 1:d3ed713f8354 | 209 | - Lower 3 bytes are variable |
loopsva | 1:d3ed713f8354 | 210 | */ |
loopsva | 1:d3ed713f8354 | 211 | uint16_t HTU21D_snc; /**< Lowest order 16 bit word of SN |
loopsva | 1:d3ed713f8354 | 212 | - Value = 0x32-- |
loopsva | 1:d3ed713f8354 | 213 | - Highest byte always = 0x32 |
loopsva | 1:d3ed713f8354 | 214 | - Lowest byte is variable |
loopsva | 1:d3ed713f8354 | 215 | */ |
loopsva | 1:d3ed713f8354 | 216 | uint8_t HTU21D_crca; /**< Single byte checksum from HTU21D_sna |
loopsva | 1:d3ed713f8354 | 217 | */ |
loopsva | 1:d3ed713f8354 | 218 | uint32_t HTU21D_crcb; /**< Four byte checksum from HTU21D_snb |
loopsva | 1:d3ed713f8354 | 219 | */ |
loopsva | 1:d3ed713f8354 | 220 | uint8_t HTU21D_crcc; /**< Single byte checksum from HTU21D_snc |
loopsva | 1:d3ed713f8354 | 221 | */ |
loopsva | 1:d3ed713f8354 | 222 | HTU21snStruct() { |
loopsva | 1:d3ed713f8354 | 223 | HTU21D_sna = 0; |
loopsva | 1:d3ed713f8354 | 224 | HTU21D_snb = 0; |
loopsva | 1:d3ed713f8354 | 225 | HTU21D_snc = 0; |
loopsva | 1:d3ed713f8354 | 226 | HTU21D_crca = 0; |
loopsva | 1:d3ed713f8354 | 227 | HTU21D_crcb = 0; |
loopsva | 1:d3ed713f8354 | 228 | HTU21D_crcc = 0; |
loopsva | 1:d3ed713f8354 | 229 | } |
loopsva | 1:d3ed713f8354 | 230 | } HTU21sn; |
loopsva | 0:2dab43acb3a4 | 231 | |
loopsva | 0:2dab43acb3a4 | 232 | private: |
loopsva | 0:2dab43acb3a4 | 233 | I2C _i2c; |
loopsva | 0:2dab43acb3a4 | 234 | /** |
loopsva | 1:d3ed713f8354 | 235 | * I2C access for getting raw Temperature and Humidity data |
loopsva | 0:2dab43acb3a4 | 236 | * |
loopsva | 1:d3ed713f8354 | 237 | * @param 8 bit HTU21D register to get data from. Must use non-blocking regs |
loopsva | 0:2dab43acb3a4 | 238 | * |
loopsva | 1:d3ed713f8354 | 239 | * @return 16 bit raw i2c data, ANDed to 14 bits 0xFFFC. 0000 if error |
loopsva | 0:2dab43acb3a4 | 240 | */ |
loopsva | 0:2dab43acb3a4 | 241 | uint16_t getData(uint8_t reg); |
loopsva | 1:d3ed713f8354 | 242 | /** |
loopsva | 1:d3ed713f8354 | 243 | * Get the HTU21D's serial number. |
loopsva | 1:d3ed713f8354 | 244 | * - Number returned is 0x4854 00-- ---- 32-- |
loopsva | 1:d3ed713f8354 | 245 | * - The numbers shown are fixed fields |
loopsva | 1:d3ed713f8354 | 246 | * - The '-' numbers are variable |
loopsva | 1:d3ed713f8354 | 247 | * |
loopsva | 1:d3ed713f8354 | 248 | * @param --none-- |
loopsva | 1:d3ed713f8354 | 249 | * |
loopsva | 1:d3ed713f8354 | 250 | * @return --none-- |
loopsva | 1:d3ed713f8354 | 251 | */ |
loopsva | 1:d3ed713f8354 | 252 | void getSNReg(); |
loopsva | 0:2dab43acb3a4 | 253 | double theTempIs; |
loopsva | 0:2dab43acb3a4 | 254 | double theHumIs; |
loopsva | 0:2dab43acb3a4 | 255 | }; |
loopsva | 0:2dab43acb3a4 | 256 | |
loopsva | 0:2dab43acb3a4 | 257 | #endif |