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R2671/Firmware/src/drivers/mpu_6050.c
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mpu_6050.c
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/*
* Copyright (C) 2017 EPFL-LSRO (Laboratoire de Systemes Robotiques).
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "mpu_6050.h"
#include <limits.h>
#include "i2c.h"
#include "../lib/utils.h"
#define GRAVITY_INTENSITY 9.81f
#define SINT16_MAX_F ((float)SHRT_MAX)
#define SLAVE_ADDRESS 0x68 ///< 0x68 if the AD0 pin is low, 0x69 otherwise.
#define REG_CONFIG 0x1A ///< Configuration register.
#define REG_GYRO_CONFIG 0x1B ///< Gyroscope configuration register.
#define REG_ACCEL_CONFIG 0x1C ///< Accelerometer configuration register.
#define REG_SMPLRT_DIV 0x19 ///< Sample rate divider register.
#define REG_ACCEL_VALUES 0x3b ///< Accelerometer measurements register.
#define REG_TEMP_VALUES 0x41 ///< Temperature measurements register.
#define REG_GYRO_VALUES 0x43 ///< Gyroscope measurements register.
#define REG_SIG_PATH_RST 0x68 ///< Signal path reset register.
#define REG_USER_CTRL 0x6A ///< User control register.
#define REG_POWER_MGMT_1 0x6B ///< Power management 1 register.
#define REG_WHO_AM_I 0x75 ///< Who am I register.
#define WHO_AM_I_VAL 0x68 ///< Expected value of the REG_WHO_AM_I register.
/// Gets the actual range value from a mpu_AccelRange enum value.
const float MPU_ACCEL_RANGE_REG_TO_CONV_FACTOR[] =
{
2.0f / SINT16_MAX_F * GRAVITY_INTENSITY,
4.0f / SINT16_MAX_F * GRAVITY_INTENSITY,
8.0f / SINT16_MAX_F * GRAVITY_INTENSITY,
16.0f / SINT16_MAX_F * GRAVITY_INTENSITY
};
/// Gets the actual range value from a mpu_GyroRange enum value.
const float MPU_GYRO_RANGE_REG_TO_CONV_FACTOR[] =
{
250.0f / SINT16_MAX_F,
500.0f / SINT16_MAX_F,
1000.0f / SINT16_MAX_F,
2000.0f / SINT16_MAX_F
};
bool mpu_initialized = false; ///< True if the MPU-6050 is initialized, false otherwise.
float accelFactor, ///< Converts a raw 16-bit integer value to an acceleration [m/s^2].
gyroFactor; ///< Converts a raw 16-bit integer value to an angular speed [deg/s].
/**
* @brief Initializes the MPU-6050 device.
* @param accelRange accelerometer range.
* @param gyroRange gyroscope range.
* @param bandwidth bandwith of the accelerometer and gyroscope.
* @return true if the initialization was successful, false otherwise.
*/
bool mpu_Init(mpu_AccelRange accelRange, mpu_GyroRange gyroRange,
mpu_Bandwidth bandwidth)
{
uint16_t id;
//
accelFactor = MPU_ACCEL_RANGE_REG_TO_CONV_FACTOR[accelRange];
gyroFactor = MPU_GYRO_RANGE_REG_TO_CONV_FACTOR[gyroRange];
// Reset the MPU-6050.
i2c_WriteRegister(SLAVE_ADDRESS, REG_POWER_MGMT_1, (1<<7)|(1<<6), NULL); // Device reset.
utils_DelayMs(100);
// Test the communication with the chip.
id = i2c_ReadRegister(SLAVE_ADDRESS, REG_WHO_AM_I, NULL);
if(id != WHO_AM_I_VAL) // Error.
return false;
// Reset the MPU-6050 again.
i2c_WriteRegister(SLAVE_ADDRESS, REG_POWER_MGMT_1,
(1<<7)|(1<<6), NULL); // Device reset.
utils_DelayMs(100);
i2c_WriteRegister(SLAVE_ADDRESS, REG_SIG_PATH_RST,
(1<<2)|(1<<1)|(1<<0), NULL); // Signal path reset.
utils_DelayMs(100);
// Setup the MPU-60X0 registers.
i2c_WriteRegister(SLAVE_ADDRESS, REG_USER_CTRL,
(0<<6) | // Disable FIFO.
(0<<5) | // Disable master mode for the external I2C sensor.
(0<<4) | // Do not disable the I2C slave interface (mandatory for the MPU-6050).
(0<<2) | // Do not reset the FIFO.
(0<<1) | // Do not reset the I2C.
(0<<0), // Do not reset the signal paths for the sensors.
NULL);
i2c_WriteRegister(SLAVE_ADDRESS, REG_POWER_MGMT_1,
(0<<7) | // Do not reset the device.
(0<<6) | // Disable sleep.
(0<<5) | // Disable the "cycle" mode.
(0<<3) | // Do not disable the temperature sensor.
(3<<0), // PLL with Z axis gyro ref.
NULL);
i2c_WriteRegister(SLAVE_ADDRESS, REG_GYRO_CONFIG,
(0<<7) | // Do not perform self-test for axis X.
(0<<6) | // Do not perform self-test for axis Y.
(0<<5) | // Do not perform self-test for axis Z.
(gyroRange<<3), // Gyroscope range.
NULL);
i2c_WriteRegister(SLAVE_ADDRESS, REG_ACCEL_CONFIG,
(0<<7) | // Do not perform self-test for axis X.
(0<<6) | // Do not perform self-test for axis Y.
(0<<5) | // Do not perform self-test for axis Z.
(accelRange<<3), // Accelerometer range.
NULL);
i2c_WriteRegister(SLAVE_ADDRESS, REG_CONFIG,
(0<<3) | // Disable synchronisation with FSYNC pin.
(bandwidth<<0), // Accelerometer and gyroscope bandwidth.
NULL);
if(bandwidth == MPU_DLPF_BW_256HZ)
i2c_WriteRegister(SLAVE_ADDRESS, REG_SMPLRT_DIV, 7, NULL);
else
i2c_WriteRegister(SLAVE_ADDRESS, REG_SMPLRT_DIV, 0, NULL);
//
mpu_initialized = true;
return true;
}
/**
* @brief Acquires the acceleration from the IMU.
* @param ax variable to write the X-axis acceleration on [m/s^2].
* @param ay variable to write the Y-axis acceleration on [m/s^2].
* @param az variable to write the Z-axis acceleration on [m/s^2].
* @remark ax, ay, and az pointer must be valid (they can't be NULL).
* @remark if the MPU-6050 is not initialized (mpu_Init() was not called
* successfully), then this function does nothing.
* @remark If the operation failed, then *ax, *ay and *az are not modified.
*/
void mpu_GetAcceleration(float *ax, float *ay, float *az)
{
bool ok;
uint8_t accelData[6];
if(!mpu_initialized)
return;
i2c_ReadMultiBytesRegister(SLAVE_ADDRESS, REG_ACCEL_VALUES,
&accelData[0], 6, &ok);
if(!ok)
return;
*ax = ((float)(int16_t)((accelData[0]<<8) | accelData[1])) * accelFactor;
*ay = ((float)(int16_t)((accelData[2]<<8) | accelData[3])) * accelFactor;
*az = ((float)(int16_t)((accelData[4]<<8) | accelData[5])) * accelFactor;
}
/**
* @brief Acquires the angular speed from the IMU.
* @param gx variable to write the X-axis angular speed on [deg/s].
* @param gy variable to write the Y-axis angular speed on [deg/s].
* @param gz variable to write the Z-axis angular speed on [deg/s].
* @remark gx, gy, and gz pointer must be valid (they can't be NULL).
* @remark if the MPU-6050 is not initialized (mpu_Init() was not called
* successfully), then this function does nothing.
* @remark If the operation failed, then *ax, *ay and *az are not modified.
*/
void mpu_GetAngularSpeed(float *gx, float *gy, float *gz)
{
bool ok;
uint8_t gyroData[6];
if(!mpu_initialized)
return;
i2c_ReadMultiBytesRegister(SLAVE_ADDRESS, REG_GYRO_VALUES,
&gyroData[0], 6, &ok);
if(!ok)
return;
*gx = ((float)(int16_t)((gyroData[0]<<8) | gyroData[1])) * gyroFactor;
*gy = ((float)(int16_t)((gyroData[2]<<8) | gyroData[3])) * gyroFactor;
*gz = ((float)(int16_t)((gyroData[4]<<8) | gyroData[5])) * gyroFactor;
}
/**
* @brief Acquires the temperature from the IMU.
* @return the measured temperature [°C], or 0 if the operation failed.
* @remark if the MPU-6050 is not initialized (mpu_Init() was not called
* successfully), then this function does nothing.
*/
float mpu_GetTemperature(void)
{
bool ok;
uint8_t tempData[2];
if(!mpu_initialized)
return 0.0f;
i2c_ReadMultiBytesRegister(SLAVE_ADDRESS, REG_TEMP_VALUES,
&tempData[0], 2, &ok);
if(!ok)
return 0.0f;
return ((float)(int16_t)((tempData[0]<<8) | tempData[1])) / 340.0f + 36.53f; // Coefs from the registers map spec.
}
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