CC2650 ST using the DMP & FIFO of the MPU 9250

Mikonos

Other Parts Discussed in Thread: CC2650, CC2650STK

I am trying to use the DMP and FIFO of the mpu 9250

I already managed to initialise the sensor (including uploading the DMP firmware to the mpu-9250) and was able to get fifo reading with some restrictions.

Unfortunaletly I am only able to get fifo reading when the fifo is read directly after initializing, and none of the other sensors is read. Whenever a different sensor is read, I stop being able to read the FIFo.

What I already tried:

- I commented out:

- pin turn off and turn on ( MPU power) PIN_setOutputValue(hGpioPin,Board_MPU_POWER, Board_MPU_POWER_OFF);

- MPU_sleep and wake up sensorMpuSleep()

- After reading all other sensors and it is time to read the fifo again (which I cant), I am able to get the who I am and get the gyro_bias and accel_bias out of the sensor. So the sensor is on and i dont think it is a I2C issue! But the fifo_count value is 0 bytes in this case. I dont think there is overflow as I also reduced the fifo rate so it needs several seconds to overflow.

- after reading all the other sensors, I re-initialised the mpu-9250 and was then able to read the fifo again (but this beats the point as I want to have all the measurements taking place when the cpu is doing something else

I am not sure how the pin interrupt works and whether this has any say in this.

PIN_setInterrupt(hGpioPin, PIN_ID(Board_MPU_INT)|PIN_IRQ_DIS); //found in SensorTag_Mov.c

Maybe power is still being turned off when reading other sensors, but I commented the api that turn power off.

SENSOR_SELECT has nothing to do with it, as I am able to have an I2C connection to read the Who I am, so no bypass issues

Any ideas what I should try next?, I am a beginner and looking forward to make this work!!

over 10 years ago

0 Jomar Hønsi over 10 years ago

TI__Expert 4095 points

Hi Mike,

As we don't use the FIFO for readout in our example code I can't give you an authoritative answer, the best bet would perhaps be to contact the manufacturer directly (InvenSense): I agree that it is unlikely to be an I2C-problem but to rule this possibility out you could strip your project down to only operate on the MPU9250. You could also try to remove the magnetometer part. This part does have a bug that we have fixed for the next release of the stack.

We have rewritten the MPU-code for the next BLE Stack release (2.1), so that it uses wake-on-motion but I doubt if this would affect how you use the FIFO.

0 Mikonos over 10 years ago in reply to Jomar Hønsi

Intellectual 330 points

Thanks Jomar,

Well I never succeded in reading the magnet from the fifo. Invensense says that this is possible, but I do not know how, and I do not care about it. I read it directly. I developed a prototype for my hardware with another chip and now I am trying to use the CC2650 as a final prototype.

the wake on motion does not use the MPU-9250 DMP feature as far as I know (might be wrong). I have succeded in uploading invensense firmware to DMP of MPU 9250. But something is happeining when other tasks are called and the DMP is reset.

My question is, would you know what happens to the pin power supply (GPIO) when TI-RTOS is working on another task? In the SensorTag_createTask(), the pin 7 output current is set to high to turn on the mpu. When the system moves to another task, what happens to the previous task pin output current? Is it maintained as is or is turned off?

Is there a way to monitor the power on pin 7 when system is working on different tasks?

0 Jomar Hønsi over 10 years ago in reply to Mikonos

TI__Expert 4095 points

The PIN power supply is not affected when running other tasks, the device stays on unless you explicitly powers it off. In the SensorTag FW as delivered this happens under two conditions:

the BLE device is disconnected
all the axes are disabled

Again I suggest stripping away all other code if you suspect the MPU to be influenced by the rest of the system. You could start with disabling the other tasks.

0 Mikonos over 10 years ago in reply to Jomar Hønsi

Intellectual 330 points

thanks, you were right.

I was having fifo overflow error, so it was nothing related to other tasks taking place.

It took a week to make this work!!

Thanks,

Mike

0 Mikonos over 10 years ago in reply to Mikonos

Intellectual 330 points

Is there any date when the new firmware is expected to be released?

0 Jomar Hønsi over 10 years ago in reply to Mikonos

TI__Expert 4095 points

There is no firm date yet, but expect it towards the end of this month.

0 Puneet Wadhawan over 10 years ago in reply to Jomar Hønsi

Intellectual 535 points

Hi MIke,
Were you trying to port the MPU driver on Sensor tag ? Can you share the steps?
Hi Jomar,
Is the new firware already released?
Regards
Puneet

0 Jomar Hønsi over 10 years ago in reply to Puneet Wadhawan

TI__Expert 4095 points

The new firmware was released 30 July. You can download it here: www.ti.com/.../ble-stack

0 Zaed over 10 years ago

Intellectual 815 points

Can you plz comment with i2c function which you are using to read the data from the fifo register, as even i am having trouble reading the fifo register. i want to read the fifo register continously in a burst.

0 Jomar Hønsi over 10 years ago in reply to Zaed

TI__Expert 4095 points

From the FIFO register you can only read one byte at a time. You shoud use sensorReadReg(FIFO_R_W, &data, 1);
I would suggest reading the FIFO count register first, and then read the number of bytes it indicates in a loop and stick them in a buffer.

0 Stephen Bishop16 over 10 years ago in reply to Jomar Hønsi

Prodigy 30 points

JOmar,

I have a project (hobby not professional) that needs to use DMP on MPU9250.

Would you be prepared to share you code to load and initiate the DMP on the sensor Tag? I hope you will.

Thanks,

Stephen

0 Stephen Bishop16 over 10 years ago

Prodigy 30 points

Mike,

I have a project (hobby not professional) that needs to use DMP on MPU9250.

Would you be prepared to share you code to load and initiate the DMP on the sensor Tag? I hope you will.

Thanks,

Stephen

0 Jomar Hønsi over 10 years ago in reply to Stephen Bishop16

TI__Expert 4095 points

The SensorTag firmware is freely available as part of the TI BLE Stack. You can download it here: http://ti.com/blestack

0 Zaed over 10 years ago in reply to Stephen Bishop16

Intellectual 815 points

Can you plz tell me how did you use dmp in your project ??? even i am trying to do that. But i can't even import the emd drivers from the invensense in to CCS studio.

0 Jomar Hønsi over 10 years ago in reply to Zaed

TI__Expert 4095 points

We don't use DMP (internal motion processing) or FIFO at all, only read and report raw data from the MPU-9250. Please have a look at the files sensor_mpu9250.c and SensorTag_Mov.c for an idea about how the MPU-9250 is used. Also note that we have only implemented a sub-set of the functionality that the chip offers. For more advanced usage, please refer to InvenSense.

0 Zaed over 10 years ago in reply to Jomar Hønsi

Intellectual 815 points

Can i integerate invensence drivers in to sensor tag's sensor_mpu9250.c and use it??? i checked the invensense emd but i am unable to import project in to my CCS

0 Jomar Hønsi over 10 years ago in reply to Zaed

TI__Expert 4095 points

Yes you can, but it's manual work - we recommend gradually adding small pieces and code from the InvenSense examples. Importing into CCS (or IAR) as such won't work, there are differences in C data types etc.

0 Zaed over 10 years ago in reply to Jomar Hønsi

Intellectual 815 points

How can i import precompiled libraries for m3, in to my sensor tag code?? (As they are some precompiled libraries in motion drivers).

0 Jomar Hønsi over 10 years ago in reply to Zaed

TI__Expert 4095 points

I would not do that. There is no guarantee these libraries will work on the CC26xx and you may cause yourself endless headaches. Please use source only when modifying the code.

0 Zaed over 10 years ago in reply to Jomar Hønsi

Intellectual 815 points

Invensense provide a set of pre-compiled libraries to be used on M3. I want to make use of these libraries as well. If the libraries are specifically compiled for m3, it should run as it is on CC26xx as well. Any reason why you think that it may not work on CC26xx?

0 Jomar Hønsi over 10 years ago in reply to Zaed

TI__Expert 4095 points

It depends what these libraries do. If they are totally generic (calculations etc.) they should work, but if they make any assumptions about GPIO, interrupt or I2C usage they will definitely not work. The SensorTag application uses TI-RTOS and if you mix in other stuff you might be in for a surprise.

0 Puneet Wadhawan over 10 years ago in reply to Jomar Hønsi

Intellectual 535 points

Hi Jomar,
Thanks for all the help and support. We are trying to compare our work with libraries provide by invensense. I understand that writing new tasks may interfear with the BLE stack and it may come as a surprise. But there should recomended ways to add new tasks to RTOS. Can you point to some examples to make use of while adding new tasks which runs at a lower priority and thus not interfears with BLE and other higher priority stuff going on.
Regards
Puneet

0 Jomar Hønsi over 10 years ago in reply to Puneet Wadhawan

TI__Expert 4095 points

On how to start task in TI-RTOS please consult the TI-RTOS documentation (available from within CCS). But a simpler way will be to studt how the SensorTag application itself starts task. You can find it in SensorTag_Tmp.c for instance. Here you can set priorities etc.

But you still have to be careful with any pre-compiled libraries: if any of these access the I2C bus or GPIO you're in trouble.

0 Zaed over 10 years ago

Intellectual 815 points

Hi,
Can you plz share the code which you used for enabling DMP in cc2650, as i am unable to do it. or how did you enable it??
Thankyou

0 Jomar Hønsi over 10 years ago in reply to Zaed

TI__Expert 4095 points

All the source code we have is available in the BLE Stack 2.1 SDK that you can download from here: http://ti.com/blestack

Please refer top the file sensor_mpu9250.c. Please also note that we don't use the MPU9250's digital motion capacity, we only read out the raw data and convert them to the respective accelerometer, gyro and magnetometer units.

0 Mikonos over 10 years ago in reply to Jomar Hønsi

Intellectual 330 points

TI does not support using the DMP + FIFO out of the CC2650STK as their target is to reduce energy consumption (probably) so they turn off the sensor between readings to save energy. Using DMP greatly increases the power consumption.

DMP has several benefits:
-Automatic Gyroscope zeroing when no movement is detected (so no need to worry about that part). By turning the gyroscope off and on, TI is making the gyroscope totally useless as you need to zero the gyroscope each time (Hope someone from TI reads this)
-Can do 6 sensor fusion(Accel+ Gyro) (so u can get pitch and roll) Yaw is not very reliable as you need to fuse the magnetometer too to get a yaw.
-Can give you low power 3sensor fusion (only accel, low power, good if there is no linear movement, otherwise useless)
- other api's available like wake on movement or get orientation or detect tapping (I did not test those yet)

It does not do any calibration for magnetometer or for accelerometer ( you have to do this on your own)

I did make this work, and I am getting the 6sensor fusion raw data out. I also managed to calibrate magnetometer and accelerometer. (gyro cal is automatically done by DMP)
I know many would like me to share this. I can post a youtube on how to do this. But I worked on this for more than a month (on and off) and had to pull my hair several times!! If you are willing to pay me a month worth of beer, I would share it :) (I drink a lot while coding)

0 Jomar Hønsi over 10 years ago in reply to Mikonos

TI__Expert 4095 points

Mike: thanks for the detailed information that we hope will benefit also other customers. Your assumption that our primary goal is to save energy is correct. We have implemented only basic functionality (reading raw data and wake-on-motion). The MPU9250 is a chip with many possibilities and within the scope of the SensorTag project it has not been possible to implement all of them. For customers wanting advanced functionality, InvenSense's own code examples is a better starting point.

0 Morgan Fitzgibbon over 10 years ago in reply to Jomar Hønsi

Expert 1360 points

Jomar,

I'm reading the number of bytes in the FIFO using a periodic clock of 100ms, and the SMPLRT_DIV set to 19 which divides the internal sample rate by 20 to give 50 Hz ... But I can't read get a consistent number of bytes for the FIFO samples counter !

How do you programme the FIFO to get a consistent count ?

Thanks

Morgan

0 Bhavya Dayananda Kattapuni over 10 years ago in reply to Mikonos

Prodigy 115 points

Hi Mike

It would be great if you would be able to help out. I have printed out the raw values from cc2650 in the CCS console using system_printf(). Now I need to print out the quaternions and use them for a application. I included the motion driver 6.12 library in CCS but as expected it does not compile.

how do I print out the quaternion values?

0 Mikonos over 10 years ago in reply to Bhavya Dayananda Kattapuni

Intellectual 330 points

Hello Bhavya,

I am writing an android app that will use the advanced features of the mpu9250 and will allow you to log the quaternion values out of the CC2650STK, among many other features. My deadline is the end of November (but this is not a rigid deadline as it is a personal project of mine).

Let me know if you have other features that you need.

So check this post soon, I will post updates.

0 Bhavya Dayananda Kattapuni over 10 years ago in reply to Mikonos

Prodigy 115 points

Hi Mike

Thank you for your reply. Have you tried to integrate Motion Driver 6.12 to the SensorTag project in cc2650 in CCS ide? It would be helpful if you could tel me how to activate the mpl library i.e. motion_driver_6.12\arm\STM32F4_MD6\Projects\eMD6\core\mpl\libmpllib.a

0 Jomar Hønsi over 10 years ago

TI__Expert 4095 points

Have you tried to contact InvenSense directly? I don't think the issues you see are related to TO hardware or software.

0 Ross Arnott over 10 years ago in reply to Mikonos

Intellectual 470 points

Hi Mike,

Have you had any problems with memory allocations when enabling the MPU9250 advanced features? I have the code compiling, but I am running into flash memory contraints when I try to enable too many features. Have you had the 9 axis sensor fusion running or are you sticking to the code that executes on the DMP only?

Any suggestions on how to optimise the memory footprint would be very welcome.

Thanks,

Ross

0 Zaed over 10 years ago in reply to Ross Arnott

Intellectual 815 points

Hi Ross,

Yes, I did 9 axis and 6 axis code both. 6 Axis code works on SensorTag with out any any issues. But when you try running 9axis Code you will run short of memory(~20KB). I tried to reduce the memory foot print for a month but of no avail. What you can do is get rid of ble stack and run only 9axis Standalone code.
SensorFusion with invensese library is only applicable for 2G and 2000DPS.

Thanks and Regards,
Faizan

0 Markus Mann over 10 years ago in reply to Zaed

Prodigy 180 points

Hi Zaed,

could you explain how you got the Sensor Fusion of MPU-9250 activated? I am struggling with this problem...

Best regards,

Markus

0 Jose Esquivel over 9 years ago

Intellectual 430 points

Hi Mikonos, would you like to share the DMP library for the CC2650? Thanks

0 Jose Esquivel over 9 years ago in reply to Zaed

Intellectual 430 points

Hi Zaed, are you able to share your code to run the DMP in the CC26050? Thanks

0 Behzad Behroozan over 9 years ago in reply to Zaed

Prodigy 60 points

Hi Zaed, It would be great if you can share the steps you took or your code. I am struggling with it as well.

Thanks,

0 Behzad Behroozan over 9 years ago in reply to Ross Arnott

Prodigy 60 points

Hi Mike,

Greatly appreciate if you share your experience. Have you had a chance to create the Youtube video?

0 EinSoldiatGott over 9 years ago in reply to Zaed

Intellectual 395 points

Hi Zaed, I've my dmp working. But it has drift and angle offset like 15deg. Did it happen to you?
e2e.ti.com/.../519008

At the end was the DMP a solution for your application? I'm thinking about implement my own integration :(.

Thanks

0 Behzad Behroozan over 9 years ago in reply to EinSoldiatGott

Prodigy 60 points

Hi @EinSoldiatGott

I am using Invensense 6.1 but getting error in CCS V6. Do you have any tutorial or steps handy how you got DMP working?

Cheers,

0 EinSoldiatGott over 9 years ago in reply to Behzad Behroozan

Intellectual 395 points

Hi, you can find my code here
e2e.ti.com/.../1885989

0 Behzad Behroozan over 9 years ago in reply to EinSoldiatGott

Prodigy 60 points

Thank you. I'll follow it and will update you.

Cheers,

0 user4264345 over 9 years ago in reply to Mikonos

Intellectual 305 points

I would be more than willing to pay you for a month of beer. I have been trying to use the DMP with the CC2650 launch pad but no luck. Could you give me a hand? Its for a school project.

Thank you!

Alejandro

0 Zaed over 9 years ago in reply to user4264345

Intellectual 815 points

If thats the case you can contact me at zfaizanz@gmail.com :) I have completely integerated the dmp code in cc2650 , I have used almost all the motion processing feature in it and even shipped the product :)

0 EinSoldiatGott over 9 years ago in reply to user4264345

Intellectual 395 points

I understand. It also took me a lot to get it working for my research project. That's why I shared the code. You can see it in the gitHub repository that I put on my original post.

I love beer :)

0 EinSoldiatGott over 9 years ago in reply to user4264345

Intellectual 395 points

e2e.ti.com/.../1885989

This is my git repo with commented progress
github.com/.../CC2650_MPU9250_DMP_2

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CC2650 ST using the DMP & FIFO of the MPU 9250