LSM9DS1.cpp

00001 /******************************************************************************
00002 SFE_LSM9DS1.cpp
00003 SFE_LSM9DS1 Library Source File
00004 Jim Lindblom @ SparkFun Electronics
00005 Original Creation Date: February 27, 2015
00006 https://github.com/sparkfun/LSM9DS1_Breakout
00007 
00008 This file implements all functions of the LSM9DS1 class. Functions here range
00009 from higher level stuff, like reading/writing LSM9DS1 registers to low-level,
00010 hardware reads and writes. Both SPI and I2C handler functions can be found
00011 towards the bottom of this file.
00012 
00013 Development environment specifics:
00014     IDE: Arduino 1.6
00015     Hardware Platform: Arduino Uno
00016     LSM9DS1 Breakout Version: 1.0
00017 
00018 This code is beerware; if you see me (or any other SparkFun employee) at the
00019 local, and you've found our code helpful, please buy us a round!
00020 
00021 Distributed as-is; no warranty is given.
00022 ******************************************************************************/
00023 
00024 #include "LSM9DS1.h"
00025 #include "LSM9DS1_Registers.h"
00026 #include "LSM9DS1_Types.h"
00027 //#include <Wire.h> // Wire library is used for I2C
00028 //#include <SPI.h>  // SPI library is used for...SPI.
00029 
00030 //#if defined(ARDUINO) && ARDUINO >= 100
00031 //  #include "Arduino.h"
00032 //#else
00033 //  #include "WProgram.h"
00034 //#endif
00035 
00036 #define LSM9DS1_COMMUNICATION_TIMEOUT 1000
00037 
00038 float magSensitivity[4] = {0.00014, 0.00029, 0.00043, 0.00058};
00039 extern Serial pc;
00040 
00041 LSM9DS1::LSM9DS1(PinName sda, PinName scl, uint8_t xgAddr, uint8_t mAddr)
00042     :i2c(sda, scl)
00043 {
00044     init(IMU_MODE_I2C, xgAddr, mAddr); // dont know about 0xD6 or 0x3B
00045 }
00046 /*
00047 LSM9DS1::LSM9DS1()
00048 {
00049     init(IMU_MODE_I2C, LSM9DS1_AG_ADDR(1), LSM9DS1_M_ADDR(1));
00050 }
00051 
00052 LSM9DS1::LSM9DS1(interface_mode interface, uint8_t xgAddr, uint8_t mAddr)
00053 {
00054     init(interface, xgAddr, mAddr);
00055 }
00056 */
00057 
00058 void LSM9DS1::init(interface_mode interface, uint8_t xgAddr, uint8_t mAddr)
00059 {
00060     settings.device.commInterface = interface;
00061     settings.device.agAddress = xgAddr;
00062     settings.device.mAddress = mAddr;
00063 
00064     settings.gyro.enabled = true;
00065     settings.gyro.enableX = true;
00066     settings.gyro.enableY = true;
00067     settings.gyro.enableZ = true;
00068     // gyro scale can be 245, 500, or 2000
00069     settings.gyro.scale = 245;
00070     // gyro sample rate: value between 1-6
00071     // 1 = 14.9    4 = 238
00072     // 2 = 59.5    5 = 476
00073     // 3 = 119     6 = 952
00074     settings.gyro.sampleRate = 6;
00075     // gyro cutoff frequency: value between 0-3
00076     // Actual value of cutoff frequency depends
00077     // on sample rate.
00078     settings.gyro.bandwidth = 0;
00079     settings.gyro.lowPowerEnable = false;
00080     settings.gyro.HPFEnable = false;
00081     // Gyro HPF cutoff frequency: value between 0-9
00082     // Actual value depends on sample rate. Only applies
00083     // if gyroHPFEnable is true.
00084     settings.gyro.HPFCutoff = 0;
00085     settings.gyro.flipX = false;
00086     settings.gyro.flipY = false;
00087     settings.gyro.flipZ = false;
00088     settings.gyro.orientation = 0;
00089     settings.gyro.latchInterrupt = true;
00090 
00091     settings.accel.enabled = true;
00092     settings.accel.enableX = true;
00093     settings.accel.enableY = true;
00094     settings.accel.enableZ = true;
00095     // accel scale can be 2, 4, 8, or 16
00096     settings.accel.scale = 2;
00097     // accel sample rate can be 1-6
00098     // 1 = 10 Hz    4 = 238 Hz
00099     // 2 = 50 Hz    5 = 476 Hz
00100     // 3 = 119 Hz   6 = 952 Hz
00101     settings.accel.sampleRate = 6;
00102     // Accel cutoff freqeuncy can be any value between -1 - 3. 
00103     // -1 = bandwidth determined by sample rate
00104     // 0 = 408 Hz   2 = 105 Hz
00105     // 1 = 211 Hz   3 = 50 Hz
00106     settings.accel.bandwidth = -1;
00107     settings.accel.highResEnable = false;
00108     // accelHighResBandwidth can be any value between 0-3
00109     // LP cutoff is set to a factor of sample rate
00110     // 0 = ODR/50    2 = ODR/9
00111     // 1 = ODR/100   3 = ODR/400
00112     settings.accel.highResBandwidth = 0;
00113 
00114     settings.mag.enabled = true;
00115     // mag scale can be 4, 8, 12, or 16
00116     settings.mag.scale = 4;
00117     // mag data rate can be 0-7
00118     // 0 = 0.625 Hz  4 = 10 Hz
00119     // 1 = 1.25 Hz   5 = 20 Hz
00120     // 2 = 2.5 Hz    6 = 40 Hz
00121     // 3 = 5 Hz      7 = 80 Hz
00122     settings.mag.sampleRate = 7;
00123     settings.mag.tempCompensationEnable = false;
00124     // magPerformance can be any value between 0-3
00125     // 0 = Low power mode      2 = high performance
00126     // 1 = medium performance  3 = ultra-high performance
00127     settings.mag.XYPerformance = 3;
00128     settings.mag.ZPerformance = 3;
00129     settings.mag.lowPowerEnable = false;
00130     // magOperatingMode can be 0-2
00131     // 0 = continuous conversion
00132     // 1 = single-conversion
00133     // 2 = power down
00134     settings.mag.operatingMode = 0;
00135 
00136     settings.temp.enabled = true;
00137     for (int i=0; i<3; i++)
00138     {
00139         gBias[i] = 0;
00140         aBias[i] = 0;
00141         mBias[i] = 0;
00142         gBiasRaw[i] = 0;
00143         aBiasRaw[i] = 0;
00144         mBiasRaw[i] = 0;
00145     }
00146     _autoCalc = false;
00147 }
00148 
00149 
00150 uint16_t LSM9DS1::begin()
00151 {
00152     //! Todo: don't use _xgAddress or _mAddress, duplicating memory
00153     _xgAddress = settings.device.agAddress;
00154     _mAddress = settings.device.mAddress;
00155     
00156     constrainScales();
00157     // Once we have the scale values, we can calculate the resolution
00158     // of each sensor. That's what these functions are for. One for each sensor
00159     calcgRes(); // Calculate DPS / ADC tick, stored in gRes variable
00160     calcmRes(); // Calculate Gs / ADC tick, stored in mRes variable
00161     calcaRes(); // Calculate g / ADC tick, stored in aRes variable
00162     
00163     // Now, initialize our hardware interface.
00164     if (settings.device.commInterface == IMU_MODE_I2C)  // If we're using I2C
00165         initI2C();  // Initialize I2C
00166     else if (settings.device.commInterface == IMU_MODE_SPI)     // else, if we're using SPI
00167         initSPI();  // Initialize SPI
00168         
00169     // To verify communication, we can read from the WHO_AM_I register of
00170     // each device. Store those in a variable so we can return them.
00171     uint8_t mTest = mReadByte(WHO_AM_I_M);      // Read the gyro WHO_AM_I
00172     uint8_t xgTest = xgReadByte(WHO_AM_I_XG);   // Read the accel/mag WHO_AM_I
00173     pc.printf("%x, %x, %x, %x\n\r", mTest, xgTest, _xgAddress, _mAddress);
00174     uint16_t whoAmICombined = (xgTest << 8) | mTest;
00175     
00176     if (whoAmICombined != ((WHO_AM_I_AG_RSP << 8) | WHO_AM_I_M_RSP))
00177         return 0;
00178     
00179     // Gyro initialization stuff:
00180     initGyro(); // This will "turn on" the gyro. Setting up interrupts, etc.
00181     
00182     // Accelerometer initialization stuff:
00183     initAccel(); // "Turn on" all axes of the accel. Set up interrupts, etc.
00184     
00185     // Magnetometer initialization stuff:
00186     initMag(); // "Turn on" all axes of the mag. Set up interrupts, etc.
00187 
00188     // Once everything is initialized, return the WHO_AM_I registers we read:
00189     return whoAmICombined;
00190 }
00191 
00192 void LSM9DS1::initGyro()
00193 {
00194     uint8_t tempRegValue = 0;
00195     
00196     // CTRL_REG1_G (Default value: 0x00)
00197     // [ODR_G2][ODR_G1][ODR_G0][FS_G1][FS_G0][0][BW_G1][BW_G0]
00198     // ODR_G[2:0] - Output data rate selection
00199     // FS_G[1:0] - Gyroscope full-scale selection
00200     // BW_G[1:0] - Gyroscope bandwidth selection
00201     
00202     // To disable gyro, set sample rate bits to 0. We'll only set sample
00203     // rate if the gyro is enabled.
00204     if (settings.gyro.enabled)
00205     {
00206         tempRegValue = (settings.gyro.sampleRate & 0x07) << 5;
00207     }
00208     switch (settings.gyro.scale)
00209     {
00210         case 500:
00211             tempRegValue |= (0x1 << 3);
00212             break;
00213         case 2000:
00214             tempRegValue |= (0x3 << 3);
00215             break;
00216         // Otherwise we'll set it to 245 dps (0x0 << 4)
00217     }
00218     tempRegValue |= (settings.gyro.bandwidth & 0x3);
00219     xgWriteByte(CTRL_REG1_G, tempRegValue);
00220     
00221     // CTRL_REG2_G (Default value: 0x00)
00222     // [0][0][0][0][INT_SEL1][INT_SEL0][OUT_SEL1][OUT_SEL0]
00223     // INT_SEL[1:0] - INT selection configuration
00224     // OUT_SEL[1:0] - Out selection configuration
00225     xgWriteByte(CTRL_REG2_G, 0x00); 
00226     
00227     // CTRL_REG3_G (Default value: 0x00)
00228     // [LP_mode][HP_EN][0][0][HPCF3_G][HPCF2_G][HPCF1_G][HPCF0_G]
00229     // LP_mode - Low-power mode enable (0: disabled, 1: enabled)
00230     // HP_EN - HPF enable (0:disabled, 1: enabled)
00231     // HPCF_G[3:0] - HPF cutoff frequency
00232     tempRegValue = settings.gyro.lowPowerEnable ? (1<<7) : 0;
00233     if (settings.gyro.HPFEnable)
00234     {
00235         tempRegValue |= (1<<6) | (settings.gyro.HPFCutoff & 0x0F);
00236     }
00237     xgWriteByte(CTRL_REG3_G, tempRegValue);
00238     
00239     // CTRL_REG4 (Default value: 0x38)
00240     // [0][0][Zen_G][Yen_G][Xen_G][0][LIR_XL1][4D_XL1]
00241     // Zen_G - Z-axis output enable (0:disable, 1:enable)
00242     // Yen_G - Y-axis output enable (0:disable, 1:enable)
00243     // Xen_G - X-axis output enable (0:disable, 1:enable)
00244     // LIR_XL1 - Latched interrupt (0:not latched, 1:latched)
00245     // 4D_XL1 - 4D option on interrupt (0:6D used, 1:4D used)
00246     tempRegValue = 0;
00247     if (settings.gyro.enableZ) tempRegValue |= (1<<5);
00248     if (settings.gyro.enableY) tempRegValue |= (1<<4);
00249     if (settings.gyro.enableX) tempRegValue |= (1<<3);
00250     if (settings.gyro.latchInterrupt) tempRegValue |= (1<<1);
00251     xgWriteByte(CTRL_REG4, tempRegValue);
00252     
00253     // ORIENT_CFG_G (Default value: 0x00)
00254     // [0][0][SignX_G][SignY_G][SignZ_G][Orient_2][Orient_1][Orient_0]
00255     // SignX_G - Pitch axis (X) angular rate sign (0: positive, 1: negative)
00256     // Orient [2:0] - Directional user orientation selection
00257     tempRegValue = 0;
00258     if (settings.gyro.flipX) tempRegValue |= (1<<5);
00259     if (settings.gyro.flipY) tempRegValue |= (1<<4);
00260     if (settings.gyro.flipZ) tempRegValue |= (1<<3);
00261     xgWriteByte(ORIENT_CFG_G, tempRegValue);
00262 }
00263 
00264 void LSM9DS1::initAccel()
00265 {
00266     uint8_t tempRegValue = 0;
00267     
00268     //  CTRL_REG5_XL (0x1F) (Default value: 0x38)
00269     //  [DEC_1][DEC_0][Zen_XL][Yen_XL][Zen_XL][0][0][0]
00270     //  DEC[0:1] - Decimation of accel data on OUT REG and FIFO.
00271     //      00: None, 01: 2 samples, 10: 4 samples 11: 8 samples
00272     //  Zen_XL - Z-axis output enabled
00273     //  Yen_XL - Y-axis output enabled
00274     //  Xen_XL - X-axis output enabled
00275     if (settings.accel.enableZ) tempRegValue |= (1<<5);
00276     if (settings.accel.enableY) tempRegValue |= (1<<4);
00277     if (settings.accel.enableX) tempRegValue |= (1<<3);
00278     
00279     xgWriteByte(CTRL_REG5_XL, tempRegValue);
00280     
00281     // CTRL_REG6_XL (0x20) (Default value: 0x00)
00282     // [ODR_XL2][ODR_XL1][ODR_XL0][FS1_XL][FS0_XL][BW_SCAL_ODR][BW_XL1][BW_XL0]
00283     // ODR_XL[2:0] - Output data rate & power mode selection
00284     // FS_XL[1:0] - Full-scale selection
00285     // BW_SCAL_ODR - Bandwidth selection
00286     // BW_XL[1:0] - Anti-aliasing filter bandwidth selection
00287     tempRegValue = 0;
00288     // To disable the accel, set the sampleRate bits to 0.
00289     if (settings.accel.enabled)
00290     {
00291         tempRegValue |= (settings.accel.sampleRate & 0x07) << 5;
00292     }
00293     switch (settings.accel.scale)
00294     {
00295         case 4:
00296             tempRegValue |= (0x2 << 3);
00297             break;
00298         case 8:
00299             tempRegValue |= (0x3 << 3);
00300             break;
00301         case 16:
00302             tempRegValue |= (0x1 << 3);
00303             break;
00304         // Otherwise it'll be set to 2g (0x0 << 3)
00305     }
00306     if (settings.accel.bandwidth >= 0)
00307     {
00308         tempRegValue |= (1<<2); // Set BW_SCAL_ODR
00309         tempRegValue |= (settings.accel.bandwidth & 0x03);
00310     }
00311     xgWriteByte(CTRL_REG6_XL, tempRegValue);
00312     
00313     // CTRL_REG7_XL (0x21) (Default value: 0x00)
00314     // [HR][DCF1][DCF0][0][0][FDS][0][HPIS1]
00315     // HR - High resolution mode (0: disable, 1: enable)
00316     // DCF[1:0] - Digital filter cutoff frequency
00317     // FDS - Filtered data selection
00318     // HPIS1 - HPF enabled for interrupt function
00319     tempRegValue = 0;
00320     if (settings.accel.highResEnable)
00321     {
00322         tempRegValue |= (1<<7); // Set HR bit
00323         tempRegValue |= (settings.accel.highResBandwidth & 0x3) << 5;
00324     }
00325     xgWriteByte(CTRL_REG7_XL, tempRegValue);
00326 }
00327 
00328 // This is a function that uses the FIFO to accumulate sample of accelerometer and gyro data, average
00329 // them, scales them to  gs and deg/s, respectively, and then passes the biases to the main sketch
00330 // for subtraction from all subsequent data. There are no gyro and accelerometer bias registers to store
00331 // the data as there are in the ADXL345, a precursor to the LSM9DS0, or the MPU-9150, so we have to
00332 // subtract the biases ourselves. This results in a more accurate measurement in general and can
00333 // remove errors due to imprecise or varying initial placement. Calibration of sensor data in this manner
00334 // is good practice.
00335 void LSM9DS1::calibrate(bool autoCalc)
00336 {  
00337     uint8_t data[6] = {0, 0, 0, 0, 0, 0};
00338     ///////////////////////////////////////////set sample number to 500
00339     uint8_t samples = 1500;
00340     int ii;
00341     int32_t aBiasRawTemp[3] = {0, 0, 0};
00342     int32_t gBiasRawTemp[3] = {0, 0, 0};
00343     
00344     // Turn on FIFO and set threshold to 32 samples
00345     enableFIFO(true);
00346     setFIFO(FIFO_THS, 0x1F);
00347     while (samples < 0x1F)
00348     {
00349         samples = (xgReadByte(FIFO_SRC) & 0x3F); // Read number of stored samples
00350     }
00351     for(ii = 0; ii < samples ; ii++) 
00352     {   // Read the gyro data stored in the FIFO
00353         readGyro();
00354         gBiasRawTemp[0] += gx;
00355         gBiasRawTemp[1] += gy;
00356         gBiasRawTemp[2] += gz;
00357         readAccel();
00358         aBiasRawTemp[0] += ax;
00359         aBiasRawTemp[1] += ay;
00360         aBiasRawTemp[2] += az - (int16_t)(1./aRes); // Assumes sensor facing up!
00361     }  
00362     for (ii = 0; ii < 3; ii++)
00363     {
00364         gBiasRaw[ii] = gBiasRawTemp[ii] / samples;
00365         gBias[ii] = calcGyro(gBiasRaw[ii]);
00366         aBiasRaw[ii] = aBiasRawTemp[ii] / samples;
00367         aBias[ii] = calcAccel(aBiasRaw[ii]);
00368     }
00369     
00370     enableFIFO(false);
00371     setFIFO(FIFO_OFF, 0x00);
00372     
00373     if (autoCalc) _autoCalc = true;
00374 }
00375 
00376 void LSM9DS1::calibrateMag(bool loadIn)
00377 {
00378     int i, j;
00379     int16_t magMin[3] = {0, 0, 0};
00380     int16_t magMax[3] = {0, 0, 0}; // The road warrior
00381     ////////////////////////////increase sample size to 1500
00382     for (i=0; i<1500; i++)
00383     {
00384         while (!magAvailable())
00385             ;
00386         readMag();
00387         int16_t magTemp[3] = {0, 0, 0};
00388         magTemp[0] = mx;        
00389         magTemp[1] = my;
00390         magTemp[2] = mz;
00391         for (j = 0; j < 3; j++)
00392         {
00393             if (magTemp[j] > magMax[j]) magMax[j] = magTemp[j];
00394             if (magTemp[j] < magMin[j]) magMin[j] = magTemp[j];
00395         }
00396     }
00397     for (j = 0; j < 3; j++)
00398     {
00399         mBiasRaw[j] = (magMax[j] + magMin[j]) / 2;
00400         mBias[j] = calcMag(mBiasRaw[j]);
00401         if (loadIn)
00402             magOffset(j, mBiasRaw[j]);
00403     }
00404     
00405 }
00406 void LSM9DS1::magOffset(uint8_t axis, int16_t offset)
00407 {
00408     if (axis > 2)
00409         return;
00410     uint8_t msb, lsb;
00411     msb = (offset & 0xFF00) >> 8;
00412     lsb = offset & 0x00FF;
00413     mWriteByte(OFFSET_X_REG_L_M + (2 * axis), lsb);
00414     mWriteByte(OFFSET_X_REG_H_M + (2 * axis), msb);
00415 }
00416 
00417 void LSM9DS1::initMag()
00418 {
00419     uint8_t tempRegValue = 0;
00420     
00421     // CTRL_REG1_M (Default value: 0x10)
00422     // [TEMP_COMP][OM1][OM0][DO2][DO1][DO0][0][ST]
00423     // TEMP_COMP - Temperature compensation
00424     // OM[1:0] - X & Y axes op mode selection
00425     //  00:low-power, 01:medium performance
00426     //  10: high performance, 11:ultra-high performance
00427     // DO[2:0] - Output data rate selection
00428     // ST - Self-test enable
00429     if (settings.mag.tempCompensationEnable) tempRegValue |= (1<<7);
00430     tempRegValue |= (settings.mag.XYPerformance & 0x3) << 5;
00431     tempRegValue |= (settings.mag.sampleRate & 0x7) << 2;
00432     mWriteByte(CTRL_REG1_M, tempRegValue);
00433     
00434     // CTRL_REG2_M (Default value 0x00)
00435     // [0][FS1][FS0][0][REBOOT][SOFT_RST][0][0]
00436     // FS[1:0] - Full-scale configuration
00437     // REBOOT - Reboot memory content (0:normal, 1:reboot)
00438     // SOFT_RST - Reset config and user registers (0:default, 1:reset)
00439     tempRegValue = 0;
00440     switch (settings.mag.scale)
00441     {
00442     case 8:
00443         tempRegValue |= (0x1 << 5);
00444         break;
00445     case 12:
00446         tempRegValue |= (0x2 << 5);
00447         break;
00448     case 16:
00449         tempRegValue |= (0x3 << 5);
00450         break;
00451     // Otherwise we'll default to 4 gauss (00)
00452     }
00453     mWriteByte(CTRL_REG2_M, tempRegValue); // +/-4Gauss
00454     
00455     // CTRL_REG3_M (Default value: 0x03)
00456     // [I2C_DISABLE][0][LP][0][0][SIM][MD1][MD0]
00457     // I2C_DISABLE - Disable I2C interace (0:enable, 1:disable)
00458     // LP - Low-power mode cofiguration (1:enable)
00459     // SIM - SPI mode selection (0:write-only, 1:read/write enable)
00460     // MD[1:0] - Operating mode
00461     //  00:continuous conversion, 01:single-conversion,
00462     //  10,11: Power-down
00463     tempRegValue = 0;
00464     if (settings.mag.lowPowerEnable) tempRegValue |= (1<<5);
00465     tempRegValue |= (settings.mag.operatingMode & 0x3);
00466     mWriteByte(CTRL_REG3_M, tempRegValue); // Continuous conversion mode
00467     
00468     // CTRL_REG4_M (Default value: 0x00)
00469     // [0][0][0][0][OMZ1][OMZ0][BLE][0]
00470     // OMZ[1:0] - Z-axis operative mode selection
00471     //  00:low-power mode, 01:medium performance
00472     //  10:high performance, 10:ultra-high performance
00473     // BLE - Big/little endian data
00474     tempRegValue = 0;
00475     tempRegValue = (settings.mag.ZPerformance & 0x3) << 2;
00476     mWriteByte(CTRL_REG4_M, tempRegValue);
00477     
00478     // CTRL_REG5_M (Default value: 0x00)
00479     // [0][BDU][0][0][0][0][0][0]
00480     // BDU - Block data update for magnetic data
00481     //  0:continuous, 1:not updated until MSB/LSB are read
00482     tempRegValue = 0;
00483     mWriteByte(CTRL_REG5_M, tempRegValue);
00484 }
00485 
00486 uint8_t LSM9DS1::accelAvailable()
00487 {
00488     uint8_t status = xgReadByte(STATUS_REG_1);
00489     
00490     return (status & (1<<0));
00491 }
00492 
00493 uint8_t LSM9DS1::gyroAvailable()
00494 {
00495     uint8_t status = xgReadByte(STATUS_REG_1);
00496     
00497     return ((status & (1<<1)) >> 1);
00498 }
00499 
00500 uint8_t LSM9DS1::tempAvailable()
00501 {
00502     uint8_t status = xgReadByte(STATUS_REG_1);
00503     
00504     return ((status & (1<<2)) >> 2);
00505 }
00506 
00507 uint8_t LSM9DS1::magAvailable(lsm9ds1_axis axis)
00508 {
00509     uint8_t status;
00510     status = mReadByte(STATUS_REG_M);
00511     
00512     return ((status & (1<<axis)) >> axis);
00513 }
00514 
00515 void LSM9DS1::readAccel()
00516 {
00517     uint8_t temp[6]; // We'll read six bytes from the accelerometer into temp   
00518     xgReadBytes(OUT_X_L_XL, temp, 6); // Read 6 bytes, beginning at OUT_X_L_XL
00519     ax = (temp[1] << 8) | temp[0]; // Store x-axis values into ax
00520     ay = (temp[3] << 8) | temp[2]; // Store y-axis values into ay
00521     az = (temp[5] << 8) | temp[4]; // Store z-axis values into az
00522     if (_autoCalc)
00523     {
00524         ax -= aBiasRaw[X_AXIS];
00525         ay -= aBiasRaw[Y_AXIS];
00526         az -= aBiasRaw[Z_AXIS];
00527     }
00528 }
00529 
00530 int16_t LSM9DS1::readAccel(lsm9ds1_axis axis)
00531 {
00532     uint8_t temp[2];
00533     int16_t value;
00534     xgReadBytes(OUT_X_L_XL + (2 * axis), temp, 2);
00535     value = (temp[1] << 8) | temp[0];
00536     
00537     if (_autoCalc)
00538         value -= aBiasRaw[axis];
00539     
00540     return value;
00541 }
00542 
00543 void LSM9DS1::readMag()
00544 {
00545     uint8_t temp[6]; // We'll read six bytes from the mag into temp 
00546     mReadBytes(OUT_X_L_M, temp, 6); // Read 6 bytes, beginning at OUT_X_L_M
00547     mx = (temp[1] << 8) | temp[0]; // Store x-axis values into mx
00548     my = (temp[3] << 8) | temp[2]; // Store y-axis values into my
00549     mz = (temp[5] << 8) | temp[4]; // Store z-axis values into mz
00550 }
00551 
00552 int16_t LSM9DS1::readMag(lsm9ds1_axis axis)
00553 {
00554     uint8_t temp[2];
00555     mReadBytes(OUT_X_L_M + (2 * axis), temp, 2);
00556     return (temp[1] << 8) | temp[0];
00557 }
00558 
00559 void LSM9DS1::readTemp()
00560 {
00561     uint8_t temp[2]; // We'll read two bytes from the temperature sensor into temp  
00562     xgReadBytes(OUT_TEMP_L, temp, 2); // Read 2 bytes, beginning at OUT_TEMP_L
00563     temperature = ((int16_t)temp[1] << 8) | temp[0];
00564 }
00565 
00566 void LSM9DS1::readGyro()
00567 {
00568     uint8_t temp[6]; // We'll read six bytes from the gyro into temp
00569     xgReadBytes(OUT_X_L_G, temp, 6); // Read 6 bytes, beginning at OUT_X_L_G
00570     gx = (temp[1] << 8) | temp[0]; // Store x-axis values into gx
00571     gy = (temp[3] << 8) | temp[2]; // Store y-axis values into gy
00572     gz = (temp[5] << 8) | temp[4]; // Store z-axis values into gz
00573     if (_autoCalc)
00574     {
00575         gx -= gBiasRaw[X_AXIS];
00576         gy -= gBiasRaw[Y_AXIS];
00577         gz -= gBiasRaw[Z_AXIS];
00578     }
00579 }
00580 
00581 int16_t LSM9DS1::readGyro(lsm9ds1_axis axis)
00582 {
00583     uint8_t temp[2];
00584     int16_t value;
00585     
00586     xgReadBytes(OUT_X_L_G + (2 * axis), temp, 2);
00587     
00588     value = (temp[1] << 8) | temp[0];
00589     
00590     if (_autoCalc)
00591         value -= gBiasRaw[axis];
00592     
00593     return value;
00594 }
00595 
00596 float LSM9DS1::calcGyro(int16_t gyro)
00597 {
00598     // Return the gyro raw reading times our pre-calculated DPS / (ADC tick):
00599     return gRes * gyro; 
00600 }
00601 
00602 float LSM9DS1::calcAccel(int16_t accel)
00603 {
00604     // Return the accel raw reading times our pre-calculated g's / (ADC tick):
00605     return aRes * accel;
00606 }
00607 
00608 float LSM9DS1::calcMag(int16_t mag)
00609 {
00610     // Return the mag raw reading times our pre-calculated Gs / (ADC tick):
00611     return mRes * mag;
00612 }
00613 
00614 void LSM9DS1::setGyroScale(uint16_t gScl)
00615 {
00616     // Read current value of CTRL_REG1_G:
00617     uint8_t ctrl1RegValue = xgReadByte(CTRL_REG1_G);
00618     // Mask out scale bits (3 & 4):
00619     ctrl1RegValue &= 0xE7;
00620     switch (gScl)
00621     {
00622         case 500:
00623             ctrl1RegValue |= (0x1 << 3);
00624             settings.gyro.scale = 500;
00625             break;
00626         case 2000:
00627             ctrl1RegValue |= (0x3 << 3);
00628             settings.gyro.scale = 2000;
00629             break;
00630         default: // Otherwise we'll set it to 245 dps (0x0 << 4)
00631             settings.gyro.scale = 245;
00632             break;
00633     }
00634     xgWriteByte(CTRL_REG1_G, ctrl1RegValue);
00635     
00636     calcgRes(); 
00637 }
00638 
00639 void LSM9DS1::setAccelScale(uint8_t aScl)
00640 {
00641     // We need to preserve the other bytes in CTRL_REG6_XL. So, first read it:
00642     uint8_t tempRegValue = xgReadByte(CTRL_REG6_XL);
00643     // Mask out accel scale bits:
00644     tempRegValue &= 0xE7;
00645     
00646     switch (aScl)
00647     {
00648         case 4:
00649             tempRegValue |= (0x2 << 3);
00650             settings.accel.scale = 4;
00651             break;
00652         case 8:
00653             tempRegValue |= (0x3 << 3);
00654             settings.accel.scale = 8;
00655             break;
00656         case 16:
00657             tempRegValue |= (0x1 << 3);
00658             settings.accel.scale = 16;
00659             break;
00660         default: // Otherwise it'll be set to 2g (0x0 << 3)
00661             settings.accel.scale = 2;
00662             break;
00663     }
00664     xgWriteByte(CTRL_REG6_XL, tempRegValue);
00665     
00666     // Then calculate a new aRes, which relies on aScale being set correctly:
00667     calcaRes();
00668 }
00669 
00670 void LSM9DS1::setMagScale(uint8_t mScl)
00671 {
00672     // We need to preserve the other bytes in CTRL_REG6_XM. So, first read it:
00673     uint8_t temp = mReadByte(CTRL_REG2_M);
00674     // Then mask out the mag scale bits:
00675     temp &= 0xFF^(0x3 << 5);
00676     
00677     switch (mScl)
00678     {
00679     case 8:
00680         temp |= (0x1 << 5);
00681         settings.mag.scale = 8;
00682         break;
00683     case 12:
00684         temp |= (0x2 << 5);
00685         settings.mag.scale = 12;
00686         break;
00687     case 16:
00688         temp |= (0x3 << 5);
00689         settings.mag.scale = 16;
00690         break;
00691     default: // Otherwise we'll default to 4 gauss (00)
00692         settings.mag.scale = 4;
00693         break;
00694     }   
00695     
00696     // And write the new register value back into CTRL_REG6_XM:
00697     mWriteByte(CTRL_REG2_M, temp);
00698     
00699     // We've updated the sensor, but we also need to update our class variables
00700     // First update mScale:
00701     //mScale = mScl;
00702     // Then calculate a new mRes, which relies on mScale being set correctly:
00703     calcmRes();
00704 }
00705 
00706 void LSM9DS1::setGyroODR(uint8_t gRate)
00707 {
00708     // Only do this if gRate is not 0 (which would disable the gyro)
00709     if ((gRate & 0x07) != 0)
00710     {
00711         // We need to preserve the other bytes in CTRL_REG1_G. So, first read it:
00712         uint8_t temp = xgReadByte(CTRL_REG1_G);
00713         // Then mask out the gyro ODR bits:
00714         temp &= 0xFF^(0x7 << 5);
00715         temp |= (gRate & 0x07) << 5;
00716         // Update our settings struct
00717         settings.gyro.sampleRate = gRate & 0x07;
00718         // And write the new register value back into CTRL_REG1_G:
00719         xgWriteByte(CTRL_REG1_G, temp);
00720     }
00721 }
00722 
00723 void LSM9DS1::setAccelODR(uint8_t aRate)
00724 {
00725     // Only do this if aRate is not 0 (which would disable the accel)
00726     if ((aRate & 0x07) != 0)
00727     {
00728         // We need to preserve the other bytes in CTRL_REG1_XM. So, first read it:
00729         uint8_t temp = xgReadByte(CTRL_REG6_XL);
00730         // Then mask out the accel ODR bits:
00731         temp &= 0x1F;
00732         // Then shift in our new ODR bits:
00733         temp |= ((aRate & 0x07) << 5);
00734         settings.accel.sampleRate = aRate & 0x07;
00735         // And write the new register value back into CTRL_REG1_XM:
00736         xgWriteByte(CTRL_REG6_XL, temp);
00737     }
00738 }
00739 
00740 void LSM9DS1::setMagODR(uint8_t mRate)
00741 {
00742     // We need to preserve the other bytes in CTRL_REG5_XM. So, first read it:
00743     uint8_t temp = mReadByte(CTRL_REG1_M);
00744     // Then mask out the mag ODR bits:
00745     temp &= 0xFF^(0x7 << 2);
00746     // Then shift in our new ODR bits:
00747     temp |= ((mRate & 0x07) << 2);
00748     settings.mag.sampleRate = mRate & 0x07;
00749     // And write the new register value back into CTRL_REG5_XM:
00750     mWriteByte(CTRL_REG1_M, temp);
00751 }
00752 
00753 void LSM9DS1::calcgRes()
00754 {
00755     gRes = ((float) settings.gyro.scale) / 32768.0;
00756 }
00757 
00758 void LSM9DS1::calcaRes()
00759 {
00760     aRes = ((float) settings.accel.scale) / 32768.0;
00761 }
00762 
00763 void LSM9DS1::calcmRes()
00764 {
00765     //mRes = ((float) settings.mag.scale) / 32768.0;
00766     switch (settings.mag.scale)
00767     {
00768     case 4:
00769         mRes = magSensitivity[0];
00770         break;
00771     case 8:
00772         mRes = magSensitivity[1];
00773         break;
00774     case 12:
00775         mRes = magSensitivity[2];
00776         break;
00777     case 16:
00778         mRes = magSensitivity[3];
00779         break;
00780     }
00781     
00782 }
00783 
00784 void LSM9DS1::configInt(interrupt_select interrupt, uint8_t generator,
00785                          h_lactive activeLow, pp_od pushPull)
00786 {
00787     // Write to INT1_CTRL or INT2_CTRL. [interupt] should already be one of
00788     // those two values.
00789     // [generator] should be an OR'd list of values from the interrupt_generators enum
00790     xgWriteByte(interrupt, generator);
00791     
00792     // Configure CTRL_REG8
00793     uint8_t temp;
00794     temp = xgReadByte(CTRL_REG8);
00795     
00796     if (activeLow) temp |= (1<<5);
00797     else temp &= ~(1<<5);
00798     
00799     if (pushPull) temp &= ~(1<<4);
00800     else temp |= (1<<4);
00801     
00802     xgWriteByte(CTRL_REG8, temp);
00803 }
00804 
00805 void LSM9DS1::configInactivity(uint8_t duration, uint8_t threshold, bool sleepOn)
00806 {
00807     uint8_t temp = 0;
00808     
00809     temp = threshold & 0x7F;
00810     if (sleepOn) temp |= (1<<7);
00811     xgWriteByte(ACT_THS, temp);
00812     
00813     xgWriteByte(ACT_DUR, duration);
00814 }
00815 
00816 uint8_t LSM9DS1::getInactivity()
00817 {
00818     uint8_t temp = xgReadByte(STATUS_REG_0);
00819     temp &= (0x10);
00820     return temp;
00821 }
00822 
00823 void LSM9DS1::configAccelInt(uint8_t generator, bool andInterrupts)
00824 {
00825     // Use variables from accel_interrupt_generator, OR'd together to create
00826     // the [generator]value.
00827     uint8_t temp = generator;
00828     if (andInterrupts) temp |= 0x80;
00829     xgWriteByte(INT_GEN_CFG_XL, temp);
00830 }
00831 
00832 void LSM9DS1::configAccelThs(uint8_t threshold, lsm9ds1_axis axis, uint8_t duration, bool wait)
00833 {
00834     // Write threshold value to INT_GEN_THS_?_XL.
00835     // axis will be 0, 1, or 2 (x, y, z respectively)
00836     xgWriteByte(INT_GEN_THS_X_XL + axis, threshold);
00837     
00838     // Write duration and wait to INT_GEN_DUR_XL
00839     uint8_t temp;
00840     temp = (duration & 0x7F);
00841     if (wait) temp |= 0x80;
00842     xgWriteByte(INT_GEN_DUR_XL, temp);
00843 }
00844 
00845 uint8_t LSM9DS1::getAccelIntSrc()
00846 {
00847     uint8_t intSrc = xgReadByte(INT_GEN_SRC_XL);
00848     
00849     // Check if the IA_XL (interrupt active) bit is set
00850     if (intSrc & (1<<6))
00851     {
00852         return (intSrc & 0x3F);
00853     }
00854     
00855     return 0;
00856 }
00857 
00858 void LSM9DS1::configGyroInt(uint8_t generator, bool aoi, bool latch)
00859 {
00860     // Use variables from accel_interrupt_generator, OR'd together to create
00861     // the [generator]value.
00862     uint8_t temp = generator;
00863     if (aoi) temp |= 0x80;
00864     if (latch) temp |= 0x40;
00865     xgWriteByte(INT_GEN_CFG_G, temp);
00866 }
00867 
00868 void LSM9DS1::configGyroThs(int16_t threshold, lsm9ds1_axis axis, uint8_t duration, bool wait)
00869 {
00870     uint8_t buffer[2];
00871     buffer[0] = (threshold & 0x7F00) >> 8;
00872     buffer[1] = (threshold & 0x00FF);
00873     // Write threshold value to INT_GEN_THS_?H_G and  INT_GEN_THS_?L_G.
00874     // axis will be 0, 1, or 2 (x, y, z respectively)
00875     xgWriteByte(INT_GEN_THS_XH_G + (axis * 2), buffer[0]);
00876     xgWriteByte(INT_GEN_THS_XH_G + 1 + (axis * 2), buffer[1]);
00877     
00878     // Write duration and wait to INT_GEN_DUR_XL
00879     uint8_t temp;
00880     temp = (duration & 0x7F);
00881     if (wait) temp |= 0x80;
00882     xgWriteByte(INT_GEN_DUR_G, temp);
00883 }
00884 
00885 uint8_t LSM9DS1::getGyroIntSrc()
00886 {
00887     uint8_t intSrc = xgReadByte(INT_GEN_SRC_G);
00888     
00889     // Check if the IA_G (interrupt active) bit is set
00890     if (intSrc & (1<<6))
00891     {
00892         return (intSrc & 0x3F);
00893     }
00894     
00895     return 0;
00896 }
00897 
00898 void LSM9DS1::configMagInt(uint8_t generator, h_lactive activeLow, bool latch)
00899 {
00900     // Mask out non-generator bits (0-4)
00901     uint8_t config = (generator & 0xE0);    
00902     // IEA bit is 0 for active-low, 1 for active-high.
00903     if (activeLow == INT_ACTIVE_HIGH) config |= (1<<2);
00904     // IEL bit is 0 for latched, 1 for not-latched
00905     if (!latch) config |= (1<<1);
00906     // As long as we have at least 1 generator, enable the interrupt
00907     if (generator != 0) config |= (1<<0);
00908     
00909     mWriteByte(INT_CFG_M, config);
00910 }
00911 
00912 void LSM9DS1::configMagThs(uint16_t threshold)
00913 {
00914     // Write high eight bits of [threshold] to INT_THS_H_M
00915     mWriteByte(INT_THS_H_M, uint8_t((threshold & 0x7F00) >> 8));
00916     // Write low eight bits of [threshold] to INT_THS_L_M
00917     mWriteByte(INT_THS_L_M, uint8_t(threshold & 0x00FF));
00918 }
00919 
00920 uint8_t LSM9DS1::getMagIntSrc()
00921 {
00922     uint8_t intSrc = mReadByte(INT_SRC_M);
00923     
00924     // Check if the INT (interrupt active) bit is set
00925     if (intSrc & (1<<0))
00926     {
00927         return (intSrc & 0xFE);
00928     }
00929     
00930     return 0;
00931 }
00932 
00933 void LSM9DS1::sleepGyro(bool enable)
00934 {
00935     uint8_t temp = xgReadByte(CTRL_REG9);
00936     if (enable) temp |= (1<<6);
00937     else temp &= ~(1<<6);
00938     xgWriteByte(CTRL_REG9, temp);
00939 }
00940 
00941 void LSM9DS1::enableFIFO(bool enable)
00942 {
00943     uint8_t temp = xgReadByte(CTRL_REG9);
00944     if (enable) temp |= (1<<1);
00945     else temp &= ~(1<<1);
00946     xgWriteByte(CTRL_REG9, temp);
00947 }
00948 
00949 void LSM9DS1::setFIFO(fifoMode_type fifoMode, uint8_t fifoThs)
00950 {
00951     // Limit threshold - 0x1F (31) is the maximum. If more than that was asked
00952     // limit it to the maximum.
00953     uint8_t threshold = fifoThs <= 0x1F ? fifoThs : 0x1F;
00954     xgWriteByte(FIFO_CTRL, ((fifoMode & 0x7) << 5) | (threshold & 0x1F));
00955 }
00956 
00957 uint8_t LSM9DS1::getFIFOSamples()
00958 {
00959     return (xgReadByte(FIFO_SRC) & 0x3F);
00960 }
00961 
00962 void LSM9DS1::constrainScales()
00963 {
00964     if ((settings.gyro.scale != 245) && (settings.gyro.scale != 500) && 
00965         (settings.gyro.scale != 2000))
00966     {
00967         settings.gyro.scale = 245;
00968     }
00969         
00970     if ((settings.accel.scale != 2) && (settings.accel.scale != 4) &&
00971         (settings.accel.scale != 8) && (settings.accel.scale != 16))
00972     {
00973         settings.accel.scale = 2;
00974     }
00975         
00976     if ((settings.mag.scale != 4) && (settings.mag.scale != 8) &&
00977         (settings.mag.scale != 12) && (settings.mag.scale != 16))
00978     {
00979         settings.mag.scale = 4;
00980     }
00981 }
00982 
00983 void LSM9DS1::xgWriteByte(uint8_t subAddress, uint8_t data)
00984 {
00985     // Whether we're using I2C or SPI, write a byte using the
00986     // gyro-specific I2C address or SPI CS pin.
00987     if (settings.device.commInterface == IMU_MODE_I2C) {
00988         printf("yo");
00989         I2CwriteByte(_xgAddress, subAddress, data);
00990     } else if (settings.device.commInterface == IMU_MODE_SPI) {
00991         SPIwriteByte(_xgAddress, subAddress, data);
00992     }
00993 }
00994 
00995 void LSM9DS1::mWriteByte(uint8_t subAddress, uint8_t data)
00996 {
00997     // Whether we're using I2C or SPI, write a byte using the
00998     // accelerometer-specific I2C address or SPI CS pin.
00999     if (settings.device.commInterface == IMU_MODE_I2C)
01000         return I2CwriteByte(_mAddress, subAddress, data);
01001     else if (settings.device.commInterface == IMU_MODE_SPI)
01002         return SPIwriteByte(_mAddress, subAddress, data);
01003 }
01004 
01005 uint8_t LSM9DS1::xgReadByte(uint8_t subAddress)
01006 {
01007     // Whether we're using I2C or SPI, read a byte using the
01008     // gyro-specific I2C address or SPI CS pin.
01009     if (settings.device.commInterface == IMU_MODE_I2C)
01010         return I2CreadByte(_xgAddress, subAddress);
01011     else if (settings.device.commInterface == IMU_MODE_SPI)
01012         return SPIreadByte(_xgAddress, subAddress);
01013 }
01014 
01015 void LSM9DS1::xgReadBytes(uint8_t subAddress, uint8_t * dest, uint8_t count)
01016 {
01017     // Whether we're using I2C or SPI, read multiple bytes using the
01018     // gyro-specific I2C address or SPI CS pin.
01019     if (settings.device.commInterface == IMU_MODE_I2C) {
01020         I2CreadBytes(_xgAddress, subAddress, dest, count);
01021     } else if (settings.device.commInterface == IMU_MODE_SPI) {
01022         SPIreadBytes(_xgAddress, subAddress, dest, count);
01023     }
01024 }
01025 
01026 uint8_t LSM9DS1::mReadByte(uint8_t subAddress)
01027 {
01028     // Whether we're using I2C or SPI, read a byte using the
01029     // accelerometer-specific I2C address or SPI CS pin.
01030     if (settings.device.commInterface == IMU_MODE_I2C)
01031         return I2CreadByte(_mAddress, subAddress);
01032     else if (settings.device.commInterface == IMU_MODE_SPI)
01033         return SPIreadByte(_mAddress, subAddress);
01034 }
01035 
01036 void LSM9DS1::mReadBytes(uint8_t subAddress, uint8_t * dest, uint8_t count)
01037 {
01038     // Whether we're using I2C or SPI, read multiple bytes using the
01039     // accelerometer-specific I2C address or SPI CS pin.
01040     if (settings.device.commInterface == IMU_MODE_I2C)
01041         I2CreadBytes(_mAddress, subAddress, dest, count);
01042     else if (settings.device.commInterface == IMU_MODE_SPI)
01043         SPIreadBytes(_mAddress, subAddress, dest, count);
01044 }
01045 
01046 void LSM9DS1::initSPI()
01047 {
01048     /* 
01049     pinMode(_xgAddress, OUTPUT);
01050     digitalWrite(_xgAddress, HIGH);
01051     pinMode(_mAddress, OUTPUT);
01052     digitalWrite(_mAddress, HIGH);
01053     
01054     SPI.begin();
01055     // Maximum SPI frequency is 10MHz, could divide by 2 here:
01056     SPI.setClockDivider(SPI_CLOCK_DIV2);
01057     // Data is read and written MSb first.
01058     SPI.setBitOrder(MSBFIRST);
01059     // Data is captured on rising edge of clock (CPHA = 0)
01060     // Base value of the clock is HIGH (CPOL = 1)
01061     SPI.setDataMode(SPI_MODE0);
01062     */
01063 }
01064 
01065 void LSM9DS1::SPIwriteByte(uint8_t csPin, uint8_t subAddress, uint8_t data)
01066 {
01067     /*
01068     digitalWrite(csPin, LOW); // Initiate communication
01069     
01070     // If write, bit 0 (MSB) should be 0
01071     // If single write, bit 1 should be 0
01072     SPI.transfer(subAddress & 0x3F); // Send Address
01073     SPI.transfer(data); // Send data
01074     
01075     digitalWrite(csPin, HIGH); // Close communication
01076     */
01077 }
01078 
01079 uint8_t LSM9DS1::SPIreadByte(uint8_t csPin, uint8_t subAddress)
01080 {
01081     uint8_t temp;
01082     // Use the multiple read function to read 1 byte. 
01083     // Value is returned to `temp`.
01084     SPIreadBytes(csPin, subAddress, &temp, 1);
01085     return temp;
01086 }
01087 
01088 void LSM9DS1::SPIreadBytes(uint8_t csPin, uint8_t subAddress,
01089                             uint8_t * dest, uint8_t count)
01090 {
01091     // To indicate a read, set bit 0 (msb) of first byte to 1
01092     uint8_t rAddress = 0x80 | (subAddress & 0x3F);
01093     // Mag SPI port is different. If we're reading multiple bytes, 
01094     // set bit 1 to 1. The remaining six bytes are the address to be read
01095     if ((csPin == _mAddress) && count > 1)
01096         rAddress |= 0x40;
01097     
01098     /* 
01099     digitalWrite(csPin, LOW); // Initiate communication
01100     SPI.transfer(rAddress);
01101     for (int i=0; i<count; i++)
01102     {
01103         dest[i] = SPI.transfer(0x00); // Read into destination array
01104     }
01105     digitalWrite(csPin, HIGH); // Close communication
01106     */
01107 }
01108 
01109 void LSM9DS1::initI2C()
01110 {
01111     /* 
01112     Wire.begin();   // Initialize I2C library
01113     */
01114     
01115     //already initialized in constructor!
01116 }
01117 
01118 // Wire.h read and write protocols
01119 void LSM9DS1::I2CwriteByte(uint8_t address, uint8_t subAddress, uint8_t data)
01120 {
01121     /* 
01122     Wire.beginTransmission(address);  // Initialize the Tx buffer
01123     Wire.write(subAddress);           // Put slave register address in Tx buffer
01124     Wire.write(data);                 // Put data in Tx buffer
01125     Wire.endTransmission();           // Send the Tx buffer
01126     */
01127     char temp_data[2] = {subAddress, data};
01128     i2c.write(address, temp_data, 2);
01129 }
01130 
01131 uint8_t LSM9DS1::I2CreadByte(uint8_t address, uint8_t subAddress)
01132 {
01133     /* 
01134     int timeout = LSM9DS1_COMMUNICATION_TIMEOUT;
01135     uint8_t data; // `data` will store the register data    
01136     
01137     Wire.beginTransmission(address);         // Initialize the Tx buffer
01138     Wire.write(subAddress);                  // Put slave register address in Tx buffer
01139     Wire.endTransmission(true);             // Send the Tx buffer, but send a restart to keep connection alive
01140     Wire.requestFrom(address, (uint8_t) 1);  // Read one byte from slave register address 
01141     while ((Wire.available() < 1) && (timeout-- > 0))
01142         delay(1);
01143     
01144     if (timeout <= 0)
01145         return 255; //! Bad! 255 will be misinterpreted as a good value.
01146     
01147     data = Wire.read();                      // Fill Rx buffer with result
01148     return data;                             // Return data read from slave register
01149     */
01150     char data;
01151     char temp[1] = {subAddress};
01152     
01153     i2c.write(address, temp, 1);
01154     //i2c.write(address & 0xFE);
01155     temp[1] = 0x00;
01156     i2c.write(address, temp, 1);
01157     //i2c.write( address | 0x01);
01158     int a = i2c.read(address, &data, 1);
01159     return data;
01160 }
01161 
01162 uint8_t LSM9DS1::I2CreadBytes(uint8_t address, uint8_t subAddress, uint8_t * dest, uint8_t count)
01163 {  
01164     /* 
01165     int timeout = LSM9DS1_COMMUNICATION_TIMEOUT;
01166     Wire.beginTransmission(address);   // Initialize the Tx buffer
01167     // Next send the register to be read. OR with 0x80 to indicate multi-read.
01168     Wire.write(subAddress | 0x80);     // Put slave register address in Tx buffer
01169 
01170     Wire.endTransmission(true);             // Send the Tx buffer, but send a restart to keep connection alive
01171     uint8_t i = 0;
01172     Wire.requestFrom(address, count);  // Read bytes from slave register address 
01173     while ((Wire.available() < count) && (timeout-- > 0))
01174         delay(1);
01175     if (timeout <= 0)
01176         return -1;
01177     
01178     for (int i=0; i<count;)
01179     {
01180         if (Wire.available())
01181         {
01182             dest[i++] = Wire.read();
01183         }
01184     }
01185     return count;
01186     */
01187     int i;
01188     char temp_dest[count];
01189     char temp[1] = {subAddress};
01190     i2c.write(address, temp, 1);
01191     i2c.read(address, temp_dest, count);
01192     
01193     //i2c doesn't take uint8_ts, but rather chars so do this nasty af conversion
01194     for (i=0; i < count; i++) {
01195         dest[i] = temp_dest[i];    
01196     }
01197     return count;
01198 }