MPU6050 Documentations

[i3130002]

I got involved in a MPU6050 project, honestly this one really hearts! No well known documentation and not having an error free code anywhere

https://www.i2cdevlib.com/devices/mpu6050#source
Due to the lack of good publicly available documentation about the inner workings of this device, all DMP-related information has been reverse-engineered from I2C signal analysis correlated against the company-provided Embedded MotionApps software

I am willing to share what I gathered over the past month or so. (Some might seems to be duplicates but they have minor differences, revision 4.2, for example is missing DMP control registers!!! )
I also include sample codes provided by the manufacturer which you can download as instructed in here

Full Docs and provided codes are available at here

[ZHomeSlice]

Thank you, the links you provided are behind Invensense developer login. I've registered with Invensense years ago. while this is helpful, I've struggled to create a functioning code that works on an Arduino UNO (atmega328p) as is. Several examples are out there that use this example code but leave out some important features. As you know there are 2 parts to the MPU. it seems that everyone has some working code for working with the registers and can get raw data from the MPU quickly. What is more difficult is gathering processed data from the DMP firmware. The Firmware register memory locations change between versions and the documentation is vague just as you mentioned. My project Simple_MPU6050 took a different approach to solve the problem. I changed and tested configurations of the DMP registers using several sketches. After determining which registers provided the best results (most useful options) I re-captured the firmware instance with registers changed prior to the start of execution. In this way, it is pre-configured for a specific purpose, although it could be re-configured to do something more/else. most of us here in the Arduino community could care less about things like android orientation etc. How my code differs: I still used Jeffs I2Cdev library but, instead of creating a function for each operation(resetFIFO(), etc.), I created macros for each register and even for each bit(s). Just place the macro in your code and it executes a common function using I2CDev library that is configured to perform the proper register/bit read/write.
My Macro naming matches the register map documentation
Example:
In the USER_CTRL resister, there is a single bit for resetting the FIFO Bit 2 and it needs to be set to the value of 1 to be reset
#define USER_CTRL_WRITE_FIFO_RST(...) MPUi2cWrite(0x6A, 1, 2, (uint8_t)1)

I am interested in implementing the 9 Deg of freedom by using the magnetometer as part of the equation. It looks to be a separately compiled library the Arduino UNO must execute. I am hoping to use that library but my skills at programming are maxing out as this is a hobby for me. :)
Your insight would be appreciated.
Z

[i3130002]

I finally acknowledge that this library is the most complex one out there but during my experiments I noticed that is is not that well designed and even has some critical flaws in it. The provided manufacturer files goes deep on how to compile DMP thus I thought there might be some source code in it to, the goal was to give others a chance to figure it out as I might not be able to do so.

[ZHomeSlice]

I also include sample codes provided by the manufacturer which you can download as instructed in here

So Go to this directory int the 6.12 download you linked to
C:...\motion_driver_6.12\msp430\eMD-6.0\core\mpl
in this directory, there is a precompiled library with a bunch of header files.
libmplmpu.lib
This is the holy grail 9 deg of freedom library. It will integrate the DMP with the Magnetometer readings to provide the 9th degree of freedom we have all been drooling over!!!

Can this library work on an atmega MPU. if so can you provide me with a compiling sketch to test?
Z

[i3130002]

Will this help ? motion_driver_6.12\msp430\eMD-6.0\core\driver\eMPL\inv_mpu.c it seems that it has compass support!
I do not have the micro you are asking for nor the compass module to test things.

[ZHomeSlice]

I can access the compass and I have DMP mostly figured out.
To access the compass you can just treat the compass as an external i2c device. the DMP doesn't use the compass at all. nothing I can see allows compass data to be passed to the DMP. As far as I can tell mixing the 6 degrees of freedom data from the DMP with the Magnetometer data from the compass requires the use of another MPU like the atmega328p. The Invensence library libmplmpu.lib is proprietary and it contains compass calibration among other things.

The MPL
The Motion Driver 6.12 contains a binary library which contains InvenSense proprietary algorithms for sensor fusion and dynamic calibration. The MD 6.12 driver pushes the sensor data into the MPL and the MPL will handle the 9-axis sensor fusion including the compass integration.

Reference: Motion Driver 6.12 – Features User Guide

Z

[i3130002]

Z

I never had to do so, in case I saw something useful will let you know. for now take a look at this wiki

[i3130002]

I was fidgeting around an saw this

In case this is what you(@ZHomeSlice ) were looking for take a look at motion_driver_6.12\arm\STM32F4_MD6\Projects\eMD6\core\driver\eMPL\inv_mpu.c to me it seems like current DMP headers are just able to make sense of either MPU6050 with AK8975_SECONDARY or MPU6500 with AK8963_SECONDARY.
Take a look and tell me if it was useful or not.

[ZHomeSlice]

MPU 6050 with compass is a MPU9150
MPU6500 with compass is a MPU9250
Better compass in the MPU9250
Slight difference in programming
The code to integrate magnetometer data with the 6 degrees of freedom is still illusive.

[i3130002]

MPU 6050 with compass is a MPU9150
MPU6500 with compass is a MPU9250
Better compass in the MPU9250
Slight difference in programming
The code to integrate magnetometer data with the 6 degrees of freedom is still illusive.

You know that when they are using another chip for magnetometer they are forced to use i2c, so what stops you from using one ?

[ZHomeSlice]

Nothing! The only advantage is that the MPU6050?MPU6500 portion of the MPU9150/ MPU9250 has the ability to access this data and store it in the magnetometer... For that fact, it could access literally any other i2c device and store its data in the MPU's memory ready for you to use possibly saving a small amount of memory and time. Just add anything to the secondary i2c input on the mpu6050 pinout. The DMP Firmware does not have any way to use data from the magnetometer and in order to get the full 9Degrees of freedom, you must use their pre-compiled library (libmplmpu.lib Found in directory motion_driver_6.12\msp430\eMD-6.0\core\mpl from this website Requires registration https://www.invensense.com/developers/login/?redirect_to=software-downloads) to integrate the magnetometer corrections into the gyro accelerometer measurements.
So any Magnetometer properly placed to gather readings could be used to integrate into the 6Degrees of freedom to correctly calibrate the gyroscope to true north. and possibly stabilize Gyro Yaw drift.

[i3130002]

motion_driver_6.12\msp430\eMD-6.0\core\mpl from this website Requires registration https://www.invensense.com/developers/login/?redirect_to=software-downloads) to integrate the

The other day I was looking around and noticed EMD v5.1.3 And I noticed that they quote "Embedded Motion Driver 5.1.3 is our six-axis version of eMD 6.1. If a compass in not required for your application, than we recommend using this" thus there is no ready to use solution in case you are using others magnetometer. In this case the only way remains is to disassemble DMP code and change i2c registers to your needs, though it would not initialize it by default if it has some configuration, you might need to do it by micro controller or doing way more low level code editing.
Does it make sense ?

[ZHomeSlice]

Yes, it just confirms that DMP has no obvious way to integrate the compass. Which if you peal the example code apart you discover compass intercession is not part of dmp but requires you to use a library. that they have created for specific processor types. if we can figure out how to make this library work with some or all the Arduino products it would provide compass integration