Reset FIFO and DMP

[mark2b]

There is a line in the acc/gyr calibration function writeByte(MPU9250_ADDRESS, MPU9250_USER_CTRL, 0x0C); // Reset FIFO and DMP Why value is 0x0C and not 0x6? 0x0C = 0b1100 Bits 2 and 3 are high But according to documentation for USER_CTRL, bit 3 is Reserved

[kriswiner]

Long story short, Invensense didn't expose DMP control register bits in their public MPU9250 documents. So bit 3 is DMP reset.

You can use 0x06, or try both and see what difference it makes (none on power-up initialization), or consult the Motion_Sense code to see how Invensense does this, or find a MPU9250 DMP application note to see how to use this register bit, etc.

On Sat, Nov 11, 2023 at 11:47 PM Mark Berner @.***> wrote:

There is a line in the acc/gyr calibration function writeByte(MPU9250_ADDRESS, MPU9250_USER_CTRL, 0x0C); // Reset FIFO and DMP Why value is 0x0C and not 0x6? 0x0C = 0b1100 Bits 2 and 3 are high But according to documentation for USER_CTRL, bit 3 is Reserved [image: Screenshot 2023-11-12 at 9 43 38] https://user-images.githubusercontent.com/539063/282285459-07d71ae7-e775-465f-91eb-c6ca9f561d98.png

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[mark2b]

Thanks for quick answer and great repository

I have another question about calibration

I'm porting this code to rust for Pico 10DOF IMU There is a code - writing accelerometer biases, for me it works when I comment out this code only

// Apparently this is not working for the acceleration biases in the MPU-9250 // Are we handling the temperature correction bit properly? // Push accelerometer biases to hardware registers writeByte(MPU9250_ADDRESS, XA_OFFSET_H, data[0]); writeByte(MPU9250_ADDRESS, XA_OFFSET_L, data[1]); writeByte(MPU9250_ADDRESS, YA_OFFSET_H, data[2]); writeByte(MPU9250_ADDRESS, YA_OFFSET_L, data[3]); writeByte(MPU9250_ADDRESS, ZA_OFFSET_H, data[4]); writeByte(MPU9250_ADDRESS, ZA_OFFSET_L, data[5]); Thanks

[kriswiner]

What is the question?

On Sun, Nov 12, 2023 at 10:38 AM Mark Berner @.***> wrote:

Thanks for quick answer and great repository

I have another question about calibration

I'm porting this code to rust for Pico 10DOF IMU There is a code - writing accelerometer biases, for me it works when I comment out this code only

// Apparently this is not working for the acceleration biases in the MPU-9250 // Are we handling the temperature correction bit properly? // Push accelerometer biases to hardware registers writeByte(MPU9250_ADDRESS, XA_OFFSET_H, data[0]); writeByte(MPU9250_ADDRESS, XA_OFFSET_L, data[1]); writeByte(MPU9250_ADDRESS, YA_OFFSET_H, data[2]); writeByte(MPU9250_ADDRESS, YA_OFFSET_L, data[3]); writeByte(MPU9250_ADDRESS, ZA_OFFSET_H, data[4]); writeByte(MPU9250_ADDRESS, ZA_OFFSET_L, data[5]);

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[mark2b]

Sorry, should I expect it works properly if I write accelerometer biases or on some boards it will not work. (on some ino files this code commented out) I'm new with IMU.

[kriswiner]

This technically works, that is, you should be able to write the accel biases to the appropriate registers, but I have found the results to be unsatisfactory since the LSB is serves double duty as some sort of indicator bit such that the biases can be slightly off. So I apply accel biases in the main loop. The gyro bias registers work fine.

On Sun, Nov 12, 2023 at 10:50 AM Mark Berner @.***> wrote:

Sorry, should I expect it works properly if I write accelerometer biases or on some boards it will not work. (on some ino files this code commented out) I'm new with IMU.

— Reply to this email directly, view it on GitHub https://github.com/kriswiner/MPU9250/issues/492#issuecomment-1807209099, or unsubscribe https://github.com/notifications/unsubscribe-auth/ABTDLKR55CXZXJTTZCPHOC3YEEK6FAVCNFSM6AAAAAA7H2SFZ2VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMYTQMBXGIYDSMBZHE . You are receiving this because you commented.Message ID: @.***>