Arduino library to support the LSM303AGR 3D accelerometer and 3D magnetometer

This sensor uses I2C to communicate. It is then required to create a TwoWire interface before accessing the sensors:

TwoWire dev_i2c(I2C2_SDA, I2C2_SCL);  
dev_i2c.begin();  

An instance can be created and enabled following the procedure below:

LSM303AGR_ACC_Sensor Acc(&dev_i2c);
Acc.begin();
Acc.Enable();
LSM303AGR_MAG_Sensor Mag(&dev_i2c);
Mag.begin();
Mag.Enable();

The access to the sensor values is done as explained below:

Read accelerometer and magnetometer.

int32_t accelerometer[3];
int32_t magnetometer[3];
Acc.GetAxes(accelerometer);
Mag.GetAxes(magnetometer);  

You can find the source files at
https://github.com/stm32duino/LSM303AGR

The LSM303AGR datasheet is available at
http:https://www.st.com/content/st_com/en/products/mems-and-sensors/e-compasses/lsm303agr.html