Mark Gottscho
A compilation of some hardware sensors and their shared programming interfaces.
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MAG3110.h
00001 /* MAG3110.h 00002 * Tested with mbed board: FRDM-KL46Z 00003 * Author: Mark Gottscho 00004 * mgottscho@ucla.edu 00005 */ 00006 00007 #ifndef MAG3110_H 00008 #define MAG3110_H 00009 00010 #include "mbed.h" 00011 #include "I2CSensor.h" 00012 #include "PeriodicSensor.h" 00013 00014 00015 /** 00016 * This class allows for easy control of an MAG3110 magnetometer IC. 00017 */ 00018 class MAG3110 : public I2CSensor, public PeriodicSensor { 00019 public: 00020 /** 00021 * Enumeration of allowed ADC sampling data rates. 00022 * The device does sample averages such that 00023 * the output data rate ODR = ADC_RATE / OVERSMPL_RATIO in all cases except for when ADC_RATE is 80 Hz (min). In this case, 00024 * there are multiple ODR for the same ADC_RATE, OVERSMPL_RATIO combination. 00025 * Note that there are non-unique combinations for the same ODR. 00026 */ 00027 typedef enum { 00028 AHZ1280, //1280 Hz 00029 AHZ640, //640 Hz 00030 AHZ320, //320 Hz 00031 AHZ160, //160 Hz 00032 AHZ80 //80 Hz 00033 } adc_smpl_rate_t; 00034 00035 /** 00036 * Enumeration of allowed oversampling ratios. 00037 * The device does sample averages such that 00038 * the output data rate ODR = ADC_RATE / OVERSMPL_RATIO in all cases except for when ADC_RATE is 80 Hz (min). In this case, 00039 * there are multiple ODR for the same ADC_RATE, OVERSMPL_RATIO combination. 00040 * Note that there are non-unique combinations for the same ODR. 00041 */ 00042 typedef enum { 00043 O16, //16:1 00044 O32, //32:1 00045 O64, //64:1 00046 O128 //128:1 00047 } oversmpl_ratio_t; 00048 00049 /** 00050 * Enumeration of possible output data rates. 00051 * The device does sample averages such that 00052 * the output data rate ODR = ADC_RATE / OVERSMPL_RATIO in all cases except for when ADC_RATE is 80 Hz (min). In this case, 00053 * there are multiple ODR for the same ADC_RATE, OVERSMPL_RATIO combination. 00054 * Note that there are non-unique combinations for the same ODR. 00055 */ 00056 typedef enum { 00057 HZ80, //80 Hz 00058 HZ40, //40 Hz 00059 HZ20, //20 Hz 00060 HZ10, //10 Hz 00061 HZ5, //5 Hz 00062 HZ2_5, //2.5 Hz 00063 HZ1_25, //1.25 Hz 00064 HZ0_63, //0.63 Hz 00065 HZ0_31, //0.31 Hz 00066 HZ0_16, //0.16 Hz 00067 HZ0_08 //0.08 Hz 00068 } smpl_rate_t; 00069 00070 /** 00071 * @param sda the pin identifier for SDA I2C signal 00072 * @param scl the pin identifier for SCL I2C signal 00073 * @param i2c_addr the 8-bit I2C address for this device. Note that LSB is a don't care. 00074 */ 00075 MAG3110 (PinName sda, PinName scl, int i2c_addr); 00076 00077 /** 00078 * 00079 */ 00080 ~MAG3110(); 00081 00082 /** 00083 * Self-initialization to some nice preset. You must ensure the device is first deactivated using setActive(). 00084 */ 00085 void selfInit(); 00086 00087 //I2C-specific methods 00088 00089 /** 00090 * Implements the pure virtual method of the parent I2CSensor class. 00091 * @returns the 8-bit device identifier. 00092 */ 00093 uint8_t whoAmI(); 00094 00095 //Device-specific methods 00096 00097 /** 00098 * @returns true if the device is active 00099 */ 00100 bool isActive (); 00101 00102 /** 00103 * @param activate if true, enables the device, else disables it 00104 */ 00105 void setActive (bool activate); 00106 00107 /** 00108 * @returns the 8-bit system mode status 00109 */ 00110 uint8_t getSystemMode (); 00111 00112 /** 00113 * @param rate optional pointer, if provided, will be set to the output sampling rate 00114 * @param ratio optional pointer, if provided, will be set to the oversampling ratio 00115 * @param adc_rate optional pointer, if provided, will be set to the ADC rate 00116 */ 00117 void getOutputSamplingParameters (smpl_rate_t *rate, oversmpl_ratio_t *ratio, adc_smpl_rate_t *adc_rate); 00118 00119 /** 00120 * @param rate the enumerated value corresponding to the output data sample rate to use 00121 * @param ratio the number of ADC samples per output sample (averaged) 00122 * @param adc_rate optional pointer, set to the resulting adc_rate used for the combination of rate and ratio 00123 * @returns true if the operation succeeded and the first two parameters were correct 00124 */ 00125 bool setOutputSamplingParameters (smpl_rate_t rate, oversmpl_ratio_t ratio, adc_smpl_rate_t *adc_rate); 00126 00127 /** 00128 * @returns the value in the data register 00129 */ 00130 uint8_t getDataRegisterStatus (); 00131 00132 00133 //Device-specific data sampling methods 00134 /** 00135 * @param sampleNow if true, queries the device for the sample and returns it. if false, gets the last queried value. 00136 * The latter is preferred if this object is set up to sample using interrupts. 00137 * @returns a 16-bit value representing the latest data sample for the X dimension, centered at 0. 00138 */ 00139 int16_t getX (bool sampleNow); 00140 00141 /** 00142 * @param sampleNow if true, queries the device for the sample and returns it. if false, gets the last queried value. 00143 * The latter is preferred if this object is set up to sample using interrupts. 00144 * @returns a 16-bit value representing the latest data sample for the Y dimension, centered at 0. 00145 */ 00146 int16_t getY (bool sampleNow); 00147 00148 /** 00149 * @param sampleNow if true, queries the device for the sample and returns it. if false, gets the last queried value. 00150 * The latter is preferred if this object is set up to sample using interrupts. 00151 * @returns a 16-bit value representing the latest data sample for the Z dimension, centered at 0. 00152 */ 00153 int16_t getZ (bool sampleNow); 00154 00155 /** 00156 * @param sampleNow if true, queries the device for the sample and returns it. if false, gets the last queried value. 00157 * The latter is preferred if this object is set up to sample using interrupts. 00158 * Returns the latest X data reading as a float in uT 00159 */ 00160 float getFloatX (bool sampleNow); 00161 00162 /** 00163 * @param sampleNow if true, queries the device for the sample and returns it. if false, gets the last queried value. 00164 * The latter is preferred if this object is set up to sample using interrupts. 00165 * Returns the latest Y data reading as a float in uT 00166 */ 00167 float getFloatY (bool sampleNow); 00168 00169 /** 00170 * @param sampleNow if true, queries the device for the sample and returns it. if false, gets the last queried value. 00171 * The latter is preferred if this object is set up to sample using interrupts. 00172 * Returns the latest Z data reading as a float in uT 00173 */ 00174 float getFloatZ (bool sampleNow); 00175 00176 /** 00177 * Get the die temperature. Note that the actual sensor range is only -40C to 125C, so not all outputs are valid. 00178 * @returns 8-bit die temperature data 00179 */ 00180 int8_t getDieTemp(); 00181 00182 /** 00183 * @returns the die temperature in deg Celsius. Note that the actual sensor range is only -40C to 125C, so not all possible outputs may be valid. 00184 */ 00185 float getFloatDieTemp (); 00186 00187 private: 00188 /** 00189 * Interrupt service routine for fetching magnetometer data from the device. 00190 */ 00191 virtual void __sample_data_ISR(); 00192 00193 ///////////////// CONSTANTS ///////////////////// 00194 00195 //Device register addresses 00196 static const uint8_t DR_STATUS = 0x00; 00197 static const uint8_t OUT_X_MSB = 0x01; 00198 static const uint8_t OUT_X_LSB = 0x02; 00199 static const uint8_t OUT_Y_MSB = 0x03; 00200 static const uint8_t OUT_Y_LSB = 0x04; 00201 static const uint8_t OUT_Z_MSB = 0x05; 00202 static const uint8_t OUT_Z_LSB = 0x06; 00203 static const uint8_t WHO_AM_I = 0x07; 00204 static const uint8_t SYSMOD = 0x08; 00205 static const uint8_t OFF_X_MSB = 0x09; 00206 static const uint8_t OFF_X_LSB = 0x0A; 00207 static const uint8_t OFF_Y_MSB = 0x0B; 00208 static const uint8_t OFF_Y_LSB = 0x0C; 00209 static const uint8_t OFF_Z_MSB = 0x0D; 00210 static const uint8_t OFF_Z_LSB = 0x0E; 00211 static const uint8_t DIE_TEMP = 0x0F; 00212 static const uint8_t CTRL_REG1 = 0x10; 00213 static const uint8_t CTRL_REG2 = 0x11; 00214 00215 //Register masks 00216 static const uint8_t DR_STATUS_ZYXOW_MASK = 0x80; //b1000 0000 00217 static const uint8_t DR_STATUS_ZOW_MASK = 0x40; //b0100 0000 00218 static const uint8_t DR_STATUS_YOW_MASK = 0x20; //b0010 0000 00219 static const uint8_t DR_STATUS_XOW_MASK = 0x10; //b0001 0000 00220 static const uint8_t DR_STATUS_ZYXDR_MASK = 0x08; //b0000 1000 00221 static const uint8_t DR_STATUS_ZDR_MASK = 0x04; //b0000 0100 00222 static const uint8_t DR_STATUS_YDR_MASK = 0x02; //b0000 0010 00223 static const uint8_t DR_STATUS_XDR_MASK = 0x01; //b0000 0001 00224 static const uint8_t SYSMOD_MASK = 0x03; //b0000 0011 00225 static const uint8_t OFF_X_LSB_MASK = 0xFE; //b1111 1110 00226 static const uint8_t OFF_Y_LSB_MASK = 0xFE; //b1111 1110 00227 static const uint8_t OFF_Z_LSB_MASK = 0xFE; //b1111 1110 00228 static const uint8_t CTRL_REG1_DR_MASK = 0xB0; //b1110 0000 00229 static const uint8_t CTRL_REG1_OS_MASK = 0x18; //b0001 1000 00230 static const uint8_t CTRL_REG1_FR_MASK = 0x04; //b0000 0100 00231 static const uint8_t CTRL_REG1_TM_MASK = 0x02; //b0000 0010 00232 static const uint8_t CTRL_REG1_AC_MASK = 0x01; //b0000 0001 00233 static const uint8_t CTRL_REG2_AUTO_MRST_EN_MASK = 0x80; //b1000 0000 00234 static const uint8_t CTRL_REG2_RAW_MASK = 0x20; //b0010 0000 00235 static const uint8_t CTRL_REG2_MAG_RST_MASK = 0x10; //b0001 0000 00236 00237 //Mapping of data values 00238 static const float TEMP_DIV = 1; //deg Celsius/level. Note that 8-bit range is -128C to 127C, but the sensor can only do -40C to 125C. 00239 static const float DATA_CONVERSION = 0.10; //uT/level 00240 00241 //////////////// VARIABLES ///////////////////// 00242 //MAG3110 state ("cached" from the values actually on the device) 00243 volatile int16_t __x; 00244 volatile int16_t __y; 00245 volatile int16_t __z; 00246 00247 bool __active; 00248 adc_smpl_rate_t __adc_rate; 00249 oversmpl_ratio_t __ratio; 00250 smpl_rate_t __rate; 00251 }; 00252 00253 #endif
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