Cannot connect to MPU-9250. It returns 0x73 instead of 0x71

[Poley09]

So everytime i try to connect, it prints this message -

MPU9250 I AM 73 I should be 71 Could not connect to MPU9250: 0x73

I have completed i2c scans and received raw data from my sensor before so i'm not sure what i'm doing wrong. Thanks in advance

[kriswiner]

Do you have I2C ports exposed? You could simply connect another board to the main board and see if the MCU and software can properly detect the WHO_AM_I.

Does this occur on all of your "professionally" designed boards?

Can't the "professionals" figure it out?

On Fri, Jun 14, 2019 at 7:48 AM amod8 notifications@github.com wrote:

Nope, we are working on a custom hardware board designed by some professional company. so depending on the hardware faults would be our last option which I think will be opting in a few days if no software faults are detected.

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[AleDanielGuerrero]

hi kris i am new and i would like to know why it is important to check the connectivity of mpu 9250 and AK8963. Since previously I was testing a code in which I did not do this check and obtained the sensor readings without any problem.

[kriswiner]

This is not important to do just good practice to check all communication paths as part of the setup and initiation. If your program works for you without doing this then there is no problem.

On Thu, Mar 26, 2020 at 8:22 AM AleDanielGuerrero notifications@github.com wrote:

hi kris i am new and i would like to know why it is important to check the connectivity of mpu 9250 and AK8963. Since previously I was testing a code in which I did not do this check and obtained the sensor readings without any problem.

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[AleDanielGuerrero]

thank you very much for answering kris

[seandepagnier]

I have a much improved unified drive for mpu9250 and mpu9255: https://github.com/seandepagnier/RTIMULib2

It actually utilizes the fifo for all the sensors and has lower noise with reduced cpu usage.

[thiagottjv]

@seandepagnier Where can I find your files for Arduino?

[seandepagnier]

I am not running this on arduino, I only use the raspberry pi, but the code may work since it's the same i2c interface.

On Mon, Apr 6, 2020 at 8:58 PM thiagottjv notifications@github.com wrote:

@seandepagnier https://github.com/seandepagnier Where can I find your files for Arduino?

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[andrasj]

Did you ever figure out the whoami value of 0x40? I'm reading the same value (over spi) from a sensor which should be a MPU9250... (The sensor is on some GNSS-receiver I bought, so I guess/hope the hardware is good. Meanwhile I've asked the vendor to confirm the sensor model is MPU9250)

inv-mpu6050-i2c 1-0068: invalid whoami 0x40 expected 0x71 (MPU9250)

[kriswiner]

Don't know what 0x40 is. 0x71 is MPU9250 and 0x73 is MPU9255. There might be others, but not that I know of....

On Thu, Jul 2, 2020 at 5:05 PM andrasj notifications@github.com wrote:

Did you ever figure out the whoami value of 0x40? I'm reading the same value (over spi) from a sensor which should be a MPU9250... (The sensor is on some GNSS-receiver I bought, so I guess/hope the hardware is good. Meanwhile I've asked the vendor to confirm the sensor model is MPU9250)

inv-mpu6050-i2c 1-0068: invalid whoami 0x40 expected 0x71 (MPU9250)

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[za3k]

Hey, I don't have any answers but thought I'd make a note as I saw this.

0x68 is documented as the "reset value" for WHO_AM_I in the MPU9250 register spec. So it's possible a reset got issued somehow, if that's accurate. (I haven't seen 0x68 returned, I just noticed this in the spec)

[andrasj]

I forgot to post a follow up on this (sorry). The vendor of my device confirmed the IMU-chip was changed from MPU9250 to ICM20948. With that information, everything started to make sense :smiley:

[HefnySco]

Don't know what 0x40 is. 0x71 is MPU9250 and 0x73 is MPU9255. There might be others, but not that I know of.... "10DOF – GY-91 4-in-1 MPU-9250 and BMP280 Multi-Sensor Module" gives me 0x73 "MPU 9250 6500" & "MPU-92/65" both gives me 0x71 This should be wrong... butI used many sensors from these models from the same seller. They all reply in the same way. This is opposite to the datasheet. Could you explain why ?

[kriswiner]

Not sure what you are asking. The WHO_AM_I for both the MPU9250 and MPU6500 should be 0x71. What is the problem?

On Wed, Aug 4, 2021 at 10:35 PM MHefny @.***> wrote:

Don't know what 0x40 is. 0x71 is MPU9250 and 0x73 is MPU9255. There might be others, but not that I know of.... "10DOF – GY-91 4-in-1 MPU-9250 and BMP280 Multi-Sensor Module" gives me 0x73 "MPU 9250 6500" & "MPU-92/65" both gives me 0x71 This should be wrong... butI used many sensors from these models from the same seller. They all reply in the same way. This is opposite to the datasheet. Could you explain why ?

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