Diff: LSM9DS0_mbed.cpp

Revision:

0:32b177f0030e

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/LSM9DS0_mbed.cpp	Sat Dec 05 16:23:36 2015 +0000
@@ -0,0 +1,427 @@
+/*
+Code by @OlimexSmart - Luca Olivieri
+This is a port from the Sparkfun library provided
+with the breakout board of the LSM9DS0.
+Visit their github for full comments:
+https://github.com/sparkfun/SparkFun_LSM9DS0_Arduino_Library/tree/V_1.0.1
+*/
+
+#include "LSM9DS0_mbed.h"
+
+LSM9DS0::LSM9DS0(PinName sdaP, PinName sclP, uint8_t gAddr, uint8_t xmAddr)
+{
+    // xmAddress and gAddress will store the 7-bit I2C address.
+    xmAddress = xmAddr;
+    gAddress = gAddr;
+
+    i2c_ = new I2C(sdaP, sclP); //This is initI2C(); in the original library
+    i2c_->frequency(400000);
+
+}
+
+uint16_t LSM9DS0::begin(gyro_scale gScl, accel_scale aScl, mag_scale mScl,
+                        gyro_odr gODR, accel_odr aODR, mag_odr mODR)
+{
+    // Store the given scales in class variables. These scale variables
+    // are used throughout to calculate the actual g's, DPS,and Gs's.
+    gScale = gScl;
+    aScale = aScl;
+    mScale = mScl;
+
+    // Once we have the scale values, we can calculate the resolution
+    // of each sensor. That's what these functions are for. One for each sensor
+    calcgRes(); // Calculate DPS / ADC tick, stored in gRes variable
+    calcmRes(); // Calculate Gs / ADC tick, stored in mRes variable
+    calcaRes(); // Calculate g / ADC tick, stored in aRes variable
+
+
+    // To verify communication, we can read from the WHO_AM_I register of
+    // each device. Store those in a variable so we can return them.
+    uint8_t gTest = gReadByte(WHO_AM_I_G);      // Read the gyro WHO_AM_I
+    uint8_t xmTest = xmReadByte(WHO_AM_I_XM);   // Read the accel/mag WHO_AM_I
+
+    // Gyro initialization stuff:
+    initGyro(); // This will "turn on" the gyro. Setting up interrupts, etc.
+    setGyroODR(gODR); // Set the gyro output data rate and bandwidth.
+    setGyroScale(gScale); // Set the gyro range
+
+    // Accelerometer initialization stuff:
+    initAccel(); // "Turn on" all axes of the accel. Set up interrupts, etc.
+    setAccelODR(aODR); // Set the accel data rate.
+    setAccelScale(aScale); // Set the accel range.
+
+    // Magnetometer initialization stuff:
+    initMag(); // "Turn on" all axes of the mag. Set up interrupts, etc.
+    setMagODR(mODR); // Set the magnetometer output data rate.
+    setMagScale(mScale); // Set the magnetometer's range.
+
+    // Once everything is initialized, return the WHO_AM_I registers we read:
+    return (xmTest << 8) | gTest;
+}
+
+void LSM9DS0::initGyro()
+{
+
+    gWriteByte(CTRL_REG1_G, 0x0F); // Normal mode, enable all axes
+    gWriteByte(CTRL_REG2_G, 0x00); // Normal mode, high cutoff frequency
+    gWriteByte(CTRL_REG3_G, 0x88);  //Interrupt enabled on both INT_G  and I2_DRDY
+    gWriteByte(CTRL_REG4_G, 0x00); // Set scale to 245 dps
+    gWriteByte(CTRL_REG5_G, 0x00); //Init default values
+
+}
+
+void LSM9DS0::initAccel()
+{
+    xmWriteByte(CTRL_REG0_XM, 0x00);
+    xmWriteByte(CTRL_REG1_XM, 0x57); // 50Hz data rate, x/y/z all enabled
+    xmWriteByte(CTRL_REG2_XM, 0x00); // Set scale to 2g
+    xmWriteByte(CTRL_REG3_XM, 0x04); // Accelerometer data ready on INT1_XM (0x04)
+
+}
+
+void LSM9DS0::initMag()
+{
+    xmWriteByte(CTRL_REG5_XM, 0x94); // Mag data rate - 100 Hz, enable temperature sensor
+    xmWriteByte(CTRL_REG6_XM, 0x00); // Mag scale to +/- 2GS
+    xmWriteByte(CTRL_REG7_XM, 0x00); // Continuous conversion mode
+    xmWriteByte(CTRL_REG4_XM, 0x04); // Magnetometer data ready on INT2_XM (0x08)
+    xmWriteByte(INT_CTRL_REG_M, 0x09); // Enable interrupts for mag, active-low, push-pull
+}
+
+// This is a function that uses the FIFO to accumulate sample of accelerometer and gyro data, average
+// them, scales them to  gs and deg/s, respectively, and then passes the biases to the main sketch
+// for subtraction from all subsequent data. There are no gyro and accelerometer bias registers to store
+// the data as there are in the ADXL345, a precursor to the LSM9DS0, or the MPU-9150, so we have to
+// subtract the biases ourselves. This results in a more accurate measurement in general and can
+// remove errors due to imprecise or varying initial placement. Calibration of sensor data in this manner
+// is good practice.
+void LSM9DS0::calLSM9DS0(float * gbias, float * abias)
+{
+    uint8_t data[6] = {0, 0, 0, 0, 0, 0};
+    int16_t gyro_bias[3] = {0, 0, 0}, accel_bias[3] = {0, 0, 0};
+    int samples, ii;
+
+    // First get gyro bias
+    uint8_t c = gReadByte(CTRL_REG5_G);
+    gWriteByte(CTRL_REG5_G, c | 0x40);         // Enable gyro FIFO
+    wait_ms(20);                                 // Wait for change to take effect
+    gWriteByte(FIFO_CTRL_REG_G, 0x20 | 0x1F);  // Enable gyro FIFO stream mode and set watermark at 32 samples
+    wait_ms(1000);  // delay 1000 milliseconds to collect FIFO samples
+
+    samples = (gReadByte(FIFO_SRC_REG_G) & 0x1F); // Read number of stored samples
+
+    for(ii = 0; ii < samples ; ii++) { // Read the gyro data stored in the FIFO
+        gReadBytes(OUT_X_L_G,  &data[0], 6);
+        gyro_bias[0] += (((int16_t)data[1] << 8) | data[0]);
+        gyro_bias[1] += (((int16_t)data[3] << 8) | data[2]);
+        gyro_bias[2] += (((int16_t)data[5] << 8) | data[4]);
+    }
+
+    gyro_bias[0] /= samples; // average the data
+    gyro_bias[1] /= samples;
+    gyro_bias[2] /= samples;
+
+    gbias[0] = (float)gyro_bias[0]*gRes;  // Properly scale the data to get deg/s
+    gbias[1] = (float)gyro_bias[1]*gRes;
+    gbias[2] = (float)gyro_bias[2]*gRes;
+
+    c = gReadByte(CTRL_REG5_G);
+    gWriteByte(CTRL_REG5_G, c & ~0x40);  // Disable gyro FIFO
+    wait_ms(20);
+    gWriteByte(FIFO_CTRL_REG_G, 0x00);   // Enable gyro bypass mode
+
+    //  Now get the accelerometer biases
+    c = xmReadByte(CTRL_REG0_XM);
+    xmWriteByte(CTRL_REG0_XM, c | 0x40);      // Enable accelerometer FIFO
+    wait_ms(20);                                // Wait for change to take effect
+    xmWriteByte(FIFO_CTRL_REG, 0x20 | 0x1F);  // Enable accelerometer FIFO stream mode and set watermark at 32 samples
+    wait_ms(1000);  // delay 1000 milliseconds to collect FIFO samples
+
+    samples = (xmReadByte(FIFO_SRC_REG) & 0x1F); // Read number of stored accelerometer samples
+
+    for(ii = 0; ii < samples ; ii++) {          // Read the accelerometer data stored in the FIFO
+        xmReadBytes(OUT_X_L_A, &data[0], 6);
+        accel_bias[0] += (((int16_t)data[1] << 8) | data[0]);
+        accel_bias[1] += (((int16_t)data[3] << 8) | data[2]);
+        accel_bias[2] += (((int16_t)data[5] << 8) | data[4]) - (int16_t)(1./aRes); // Assumes sensor facing up!
+    }
+
+    accel_bias[0] /= samples; // average the data
+    accel_bias[1] /= samples;
+    accel_bias[2] /= samples;
+
+    abias[0] = (float)accel_bias[0]*aRes; // Properly scale data to get gs
+    abias[1] = (float)accel_bias[1]*aRes;
+    abias[2] = (float)accel_bias[2]*aRes;
+
+    c = xmReadByte(CTRL_REG0_XM);
+    xmWriteByte(CTRL_REG0_XM, c & ~0x40);    // Disable accelerometer FIFO
+    wait_ms(20);
+    xmWriteByte(FIFO_CTRL_REG, 0x00);       // Enable accelerometer bypass mode
+
+}
+void LSM9DS0::readAccel()
+{
+    uint8_t temp[6]; // We'll read six bytes from the accelerometer into temp
+    xmReadBytes(OUT_X_L_A, temp, 6); // Read 6 bytes, beginning at OUT_X_L_A
+    ax = (temp[1] << 8) | temp[0]; // Store x-axis values into ax
+    ay = (temp[3] << 8) | temp[2]; // Store y-axis values into ay
+    az = (temp[5] << 8) | temp[4]; // Store z-axis values into az
+
+}
+
+void LSM9DS0::readMag()
+{
+    uint8_t temp[6]; // We'll read six bytes from the mag into temp
+    xmReadBytes(OUT_X_L_M, temp, 6); // Read 6 bytes, beginning at OUT_X_L_M
+    mx = (temp[1] << 8) | temp[0]; // Store x-axis values into mx
+    my = (temp[3] << 8) | temp[2]; // Store y-axis values into my
+    mz = (temp[5] << 8) | temp[4]; // Store z-axis values into mz
+}
+
+void LSM9DS0::readTemp()
+{
+    uint8_t temp[2]; // We'll read two bytes from the temperature sensor into temp
+    xmReadBytes(OUT_TEMP_L_XM, temp, 2); // Read 2 bytes, beginning at OUT_TEMP_L_XM
+    //temperature = (((int16_t) temp[1] << 12) | temp[0] << 4 ) >> 4; // Temperature is a 12-bit signed integer
+    
+    uint8_t xlo = temp[0];
+    int16_t xhi = temp[1];
+    xhi <<= 8;
+    xhi |= xlo;
+    temperature = xhi;
+}
+
+
+void LSM9DS0::readGyro()
+{
+    uint8_t temp[6]; // We'll read six bytes from the gyro into temp
+    gReadBytes(OUT_X_L_G, temp, 6); // Read 6 bytes, beginning at OUT_X_L_G
+    gx = (temp[1] << 8) | temp[0]; // Store x-axis values into gx
+    gy = (temp[3] << 8) | temp[2]; // Store y-axis values into gy
+    gz = (temp[5] << 8) | temp[4]; // Store z-axis values into gz
+}
+
+float LSM9DS0::calcGyro(int16_t gyro)
+{
+    // Return the gyro raw reading times our pre-calculated DPS / (ADC tick):
+    return gRes * gyro;
+}
+
+float LSM9DS0::calcAccel(int16_t accel)
+{
+    // Return the accel raw reading times our pre-calculated g's / (ADC tick):
+    return aRes * accel;
+}
+
+float LSM9DS0::calcMag(int16_t mag)
+{
+    // Return the mag raw reading times our pre-calculated Gs / (ADC tick):
+    return mRes * mag;
+}
+
+void LSM9DS0::setGyroScale(gyro_scale gScl)
+{
+    // We need to preserve the other bytes in CTRL_REG4_G. So, first read it:
+    uint8_t temp = gReadByte(CTRL_REG4_G);
+    // Then mask out the gyro scale bits:
+    temp &= 0xFF^(0x3 << 4);
+    // Then shift in our new scale bits:
+    temp |= gScl << 4;
+    // And write the new register value back into CTRL_REG4_G:
+    gWriteByte(CTRL_REG4_G, temp);
+
+    // We've updated the sensor, but we also need to update our class variables
+    // First update gScale:
+    gScale = gScl;
+    // Then calculate a new gRes, which relies on gScale being set correctly:
+    calcgRes();
+}
+
+void LSM9DS0::setAccelScale(accel_scale aScl)
+{
+    // We need to preserve the other bytes in CTRL_REG2_XM. So, first read it:
+    uint8_t temp = xmReadByte(CTRL_REG2_XM);
+    // Then mask out the accel scale bits:
+    temp &= 0xFF^(0x3 << 3);
+    // Then shift in our new scale bits:
+    temp |= aScl << 3;
+    // And write the new register value back into CTRL_REG2_XM:
+    xmWriteByte(CTRL_REG2_XM, temp);
+
+    // We've updated the sensor, but we also need to update our class variables
+    // First update aScale:
+    aScale = aScl;
+    // Then calculate a new aRes, which relies on aScale being set correctly:
+    calcaRes();
+}
+
+void LSM9DS0::setMagScale(mag_scale mScl)
+{
+    // We need to preserve the other bytes in CTRL_REG6_XM. So, first read it:
+    uint8_t temp = xmReadByte(CTRL_REG6_XM);
+    // Then mask out the mag scale bits:
+    temp &= 0xFF^(0x3 << 5);
+    // Then shift in our new scale bits:
+    temp |= mScl << 5;
+    // And write the new register value back into CTRL_REG6_XM:
+    xmWriteByte(CTRL_REG6_XM, temp);
+
+    // We've updated the sensor, but we also need to update our class variables
+    // First update mScale:
+    mScale = mScl;
+    // Then calculate a new mRes, which relies on mScale being set correctly:
+    calcmRes();
+}
+
+void LSM9DS0::setGyroODR(gyro_odr gRate)
+{
+    // We need to preserve the other bytes in CTRL_REG1_G. So, first read it:
+    uint8_t temp = gReadByte(CTRL_REG1_G);
+    // Then mask out the gyro ODR bits:
+    temp &= 0xFF^(0xF << 4);
+    // Then shift in our new ODR bits:
+    temp |= (gRate << 4);
+    // And write the new register value back into CTRL_REG1_G:
+    gWriteByte(CTRL_REG1_G, temp);
+}
+
+void LSM9DS0::setAccelODR(accel_odr aRate)
+{
+    // We need to preserve the other bytes in CTRL_REG1_XM. So, first read it:
+    uint8_t temp = xmReadByte(CTRL_REG1_XM);
+    // Then mask out the accel ODR bits:
+    temp &= 0xFF^(0xF << 4);
+    // Then shift in our new ODR bits:
+    temp |= (aRate << 4);
+    // And write the new register value back into CTRL_REG1_XM:
+    xmWriteByte(CTRL_REG1_XM, temp);
+}
+
+void LSM9DS0::setMagODR(mag_odr mRate)
+{
+    // We need to preserve the other bytes in CTRL_REG5_XM. So, first read it:
+    uint8_t temp = xmReadByte(CTRL_REG5_XM);
+    // Then mask out the mag ODR bits:
+    temp &= 0xFF^(0x7 << 2);
+    // Then shift in our new ODR bits:
+    temp |= (mRate << 2);
+    // And write the new register value back into CTRL_REG5_XM:
+    xmWriteByte(CTRL_REG5_XM, temp);
+}
+
+void LSM9DS0::setAccelABW(accel_abw abwRate)
+{
+    // We need to preserve the other bytes in CTRL_REG2_XM. So, first read it:
+    uint8_t temp = xmReadByte(CTRL_REG2_XM);
+    // Then mask out the accel ABW bits:
+    temp &= 0xFF^(0x3 << 7);
+    // Then shift in our new ODR bits:
+    temp |= (abwRate << 7);
+    // And write the new register value back into CTRL_REG2_XM:
+    xmWriteByte(CTRL_REG2_XM, temp);
+}
+
+void LSM9DS0::calcgRes()
+{
+    // Possible gyro scales (and their register bit settings) are:
+    // 245 DPS (00), 500 DPS (01), 2000 DPS (10). Here's a bit of an algorithm
+    // to calculate DPS/(ADC tick) based on that 2-bit value:
+    switch (gScale) {
+        case G_SCALE_245DPS:
+            gRes = 245.0 / 32768.0;
+            break;
+        case G_SCALE_500DPS:
+            gRes = 500.0 / 32768.0;
+            break;
+        case G_SCALE_2000DPS:
+            gRes = 2000.0 / 32768.0;
+            break;
+    }
+}
+
+void LSM9DS0::calcaRes()
+{
+    // Possible accelerometer scales (and their register bit settings) are:
+    // 2 g (000), 4g (001), 6g (010) 8g (011), 16g (100). Here's a bit of an
+    // algorithm to calculate g/(ADC tick) based on that 3-bit value:
+    aRes = aScale == A_SCALE_16G ? 16.0 / 32768.0 :
+           (((float) aScale + 1.0) * 2.0) / 32768.0;
+}
+
+void LSM9DS0::calcmRes()
+{
+    // Possible magnetometer scales (and their register bit settings) are:
+    // 2 Gs (00), 4 Gs (01), 8 Gs (10) 12 Gs (11). Here's a bit of an algorithm
+    // to calculate Gs/(ADC tick) based on that 2-bit value:
+    mRes = mScale == M_SCALE_2GS ? 2.0 / 32768.0 :
+           (float) (mScale << 2) / 32768.0;
+}
+
+void LSM9DS0::gWriteByte(uint8_t subAddress, uint8_t data)
+{
+    // Whether we're using I2C or SPI, write a byte using the
+    // gyro-specific I2C address or SPI CS pin.
+    I2CwriteByte(gAddress, subAddress, data);
+}
+
+void LSM9DS0::xmWriteByte(uint8_t subAddress, uint8_t data)
+{
+    // Whether we're using I2C or SPI, write a byte using the
+    // accelerometer-specific I2C address or SPI CS pin.
+    return I2CwriteByte(xmAddress, subAddress, data);
+}
+
+uint8_t LSM9DS0::gReadByte(uint8_t subAddress)
+{
+    return I2CreadByte(gAddress, subAddress);
+}
+
+void LSM9DS0::gReadBytes(uint8_t subAddress, uint8_t * dest, uint8_t count)
+{
+    // Whether we're using I2C or SPI, read multiple bytes using the
+    // gyro-specific I2C address.
+    I2CreadBytes(gAddress, subAddress, dest, count);
+}
+
+uint8_t LSM9DS0::xmReadByte(uint8_t subAddress)
+{
+    // Whether we're using I2C or SPI, read a byte using the
+    // accelerometer-specific I2C address.
+    return I2CreadByte(xmAddress, subAddress);
+}
+
+void LSM9DS0::xmReadBytes(uint8_t subAddress, uint8_t * dest, uint8_t count)
+{
+    // read multiple bytes using the
+    // accelerometer-specific I2C address.
+    I2CreadBytes(xmAddress, subAddress, dest, count);
+}
+
+
+//I2C rewritten to accomodate i2cdev instead of Wire (Arduino)
+void LSM9DS0::I2CwriteByte(uint8_t address, uint8_t subAddress, uint8_t data)
+{
+    char dt[2];              // Initialize the Tx buffer
+    dt[0] = subAddress;         // Put slave register address in Tx buffer
+    dt[1] = data;               // Put data in Tx buffer
+    i2c_->write(address << 1, dt, 2); // Send the Tx buffer
+}
+
+uint8_t LSM9DS0::I2CreadByte(uint8_t address, uint8_t subAddress)
+{
+    i2c_->write(address << 1, (char*)&subAddress, 1, true);  // Send request, but keep connection alive
+    char dt = 0;
+    i2c_->read(address << 1, &dt, 1);                 // Fill Rx buffer with result
+
+    return dt;                                  // Return data read from slave register
+
+}
+
+void LSM9DS0::I2CreadBytes(uint8_t address, uint8_t subAddress, uint8_t * dest,
+                           uint8_t count)
+{
+    char sA = subAddress | 0x80;         // Send the register to be read. OR with 0x80 to indicate multi-read.
+    i2c_->write(address << 1, &sA, 1, true);      // Send the Tx buffer, but keep connection alive
+    i2c_->read(address << 1, (char*)dest, count);        // Read bytes from slave register address
+}