IMU Sensor Chip
Last updated
Last updated
The board contains the LSM9DS1 sensor chip that provides the following functions:
3D Accelerometer
3D Gyroscope
3D Magnetometer
Thermometer
In the moment software is using only the first 3 sensors. The thermometer is not used. Official documentation on the chip can be found here:
This chip has a lot of registers inside. It is easy to get lost in them. So, here is the summary of all those registers:
The list is broken into multiple sub tables to simplify reading and understanding. The first 2 columns describe accelerometer and gyroscope, while the third column - magnetometer. You can see that magnetometer has its own registers numbering. This is because accelerometer + gyroscope comprise one i2c device while magnetometer is another i2C device. They have different i2c addresses while still reside in the same package. On the PCB they look like one chip.
The color coding on the table describes the purpose of the registers. This helps breaking registers into groups.
Registers with white background are either a R/W configuration registers or a R/O status registers.
Registers with light green background are all interrupt configuration registers or show the current status of interrupts. Since interrupts from this chip are not accessible on the CPU, the interrupts are not used in this project. So, documentation on all these registers can be skipped. They will not be discussed any further again.
Registers with light orange background always return known constant value. They provide simple way to check that the chip on the other side of the i2C bus is responding.
Registers with light blue background are data registers. Application gets sensor data from the chip by reading them.
