I2C Library for the LSM9DS0 IMU
Dependents: 4180_LSM9DS0_lab HW2_P2 HW2_P3 HW2_P4 ... more
LSM9DS0.cpp
- Committer:
- aswild
- Date:
- 2015-02-02
- Revision:
- 2:5556e6fb99f5
- Parent:
- 0:3a1dce39106c
File content as of revision 2:5556e6fb99f5:
#include "LSM9DS0.h" #include "math.h" LSM9DS0::LSM9DS0(PinName sda, PinName scl, uint8_t gAddr, uint8_t xmAddr) : i2c(sda, scl) { // xmAddress and gAddress will store the 7-bit I2C address, if using I2C. xmAddress = xmAddr; gAddress = gAddr; } 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 } void LSM9DS0::readAccel() { uint16_t data = 0; //Get x data = xmReadByte(OUT_X_H_A); data <<= 8; data |= xmReadByte(OUT_X_L_A); ax_raw = data; ax = ax_raw * aRes; //Get y data=0; data = xmReadByte(OUT_Y_H_A); data <<= 8; data |= xmReadByte(OUT_Y_L_A); ay_raw = data; ay = ay_raw * aRes; //Get z data=0; data = xmReadByte(OUT_Z_H_A); data <<= 8; data |= xmReadByte(OUT_Z_L_A); az_raw = data; az = az_raw * aRes; } void LSM9DS0::readMag() { uint16_t data = 0; //Get x data = xmReadByte(OUT_X_H_M); data <<= 8; data |= xmReadByte(OUT_X_L_M); mx_raw = data; mx = mx_raw * mRes; //Get y data = xmReadByte(OUT_Y_H_M); data <<= 8; data |= xmReadByte(OUT_Y_L_M); my_raw = data; my = my_raw * mRes; //Get z data = xmReadByte(OUT_Z_H_M); data <<= 8; data |= xmReadByte(OUT_Z_L_M); mz_raw = data; mz = mz_raw * mRes; } void LSM9DS0::readTemp() { uint8_t temp[2]; // We'll read two bytes from the temperature sensor into temp temp[0] = xmReadByte(OUT_TEMP_L_XM); temp[1] = xmReadByte(OUT_TEMP_H_XM); // Temperature is a 12-bit signed integer temperature_raw = (((int16_t) temp[1] << 12) | temp[0] << 4 ) >> 4; temperature_c = (float)temperature_raw / 8.0 + 25; temperature_f = temperature_c * 1.8 + 32; } void LSM9DS0::readGyro() { uint16_t data = 0; //Get x data = gReadByte(OUT_X_H_G); data <<= 8; data |= gReadByte(OUT_X_L_G); gx_raw = data; gx = gx_raw * gRes; //Get y data = gReadByte(OUT_Y_H_G); data <<= 8; data |= gReadByte(OUT_Y_L_G); gy_raw = data; gy = gy_raw * gRes; //Get z data = gReadByte(OUT_Z_H_G); data <<= 8; data |= gReadByte(OUT_Z_L_G); gz_raw = data; gz = gz_raw * gRes; } 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::configGyroInt(uint8_t int1Cfg, uint16_t int1ThsX, uint16_t int1ThsY, uint16_t int1ThsZ, uint8_t duration) { gWriteByte(INT1_CFG_G, int1Cfg); gWriteByte(INT1_THS_XH_G, (int1ThsX & 0xFF00) >> 8); gWriteByte(INT1_THS_XL_G, (int1ThsX & 0xFF)); gWriteByte(INT1_THS_YH_G, (int1ThsY & 0xFF00) >> 8); gWriteByte(INT1_THS_YL_G, (int1ThsY & 0xFF)); gWriteByte(INT1_THS_ZH_G, (int1ThsZ & 0xFF00) >> 8); gWriteByte(INT1_THS_ZL_G, (int1ThsZ & 0xFF)); if (duration) gWriteByte(INT1_DURATION_G, 0x80 | duration); else gWriteByte(INT1_DURATION_G, 0x00); } 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; } #define R2D 57.295779513F // calculate compass heading, assuming readMag() has been called already float LSM9DS0::calcHeading() { if (my > 0) return 90.0 - atan(mx / my)*R2D; else if (my < 0) return 270.0 - atan(mx / my)*R2D; else if (mx < 0) return 180.0; else return 0.0; } void LSM9DS0::calcBias() { 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 data[0] = gReadByte(OUT_X_L_G); data[1] = gReadByte(OUT_X_H_G); data[2] = gReadByte(OUT_Y_L_G); data[3] = gReadByte(OUT_Y_H_G); data[4] = gReadByte(OUT_Z_L_G); data[5] = gReadByte(OUT_Z_H_G); 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 data[0] = xmReadByte(OUT_X_L_A); data[1] = xmReadByte(OUT_X_H_A); data[2] = xmReadByte(OUT_Y_L_A); data[3] = xmReadByte(OUT_Y_H_A); data[4] = xmReadByte(OUT_Z_L_A); data[5] = xmReadByte(OUT_Z_H_A); 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::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); } 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::I2CwriteByte(char address, char subAddress, char data) { char cmd[2] = {subAddress, data}; i2c.write(address<<1, cmd, 2); } uint8_t LSM9DS0::I2CreadByte(char address, char subAddress) { char data; // store the register data i2c.write(address<<1, &subAddress, 1, true); i2c.read(address<<1, &data, 1); return data; }