SmartMotion® MEMS Motion Sensors

Hello,

I am trying to read the WHO_AM_I registers on the MPU9250 to check that the I2C communications are working correctly. There are two WHO_AM_I registers, one for the 9250 section (accelerometer and gyroscope) and one for the magnetometer section, (AK8963).
I can successfully read the 9250 WHO_AM_I using the following sequence:

I2C Start
Transmit byte 0xD0 (9250 ID)
Transmit byte 0x75 (9250 WHO_AM_I)
I2C Restart
Transmit byte 0xD1
Who_9250 = Receive Byte
I2C Stop

This reads 0x71 which is correct.

Hi,

I am experiencing a problem when measuring angle

I am using this formula, so I get a 0 – 127 range
pitch = atan2(accele_x, accele_z) * 80.8507;

I have a MPU6000 connected to a MCU through SPI. No INT pin used. In main cycle MCU is continously reading FIFO_COUNT, and reads out FIFO if FIFO_COUNT>=12 (6*16bit data to read: 6axis only, no external I2C slaves and no TEMP data). The problem is FIFO_COUNT always reads 0.
SPI communication seems to work well, as reading WHO_AM_I(0x75) register responds 0x68 which is correct (checking SCK, MISO, MOSI, CS lines with logic analyzer).

Initialization:

Is it possible to access DMP data if my MPU 9250 INT PIN is floating ?

I'd like to download application notes such as self test and calibration processes the spec sheet promised there would be downloads available. The spec sheet says nothing about how the device should be operated at all. Where are the downloads?

I realize that to use SPI I need to disable the initial I2C interface, and that I do this by setting bit 4 of register 3. But since SPI doesn't initially work, it appears that I have to use I2C to set that bit. So I have to use I2C just long enough to turn itself off so I can switch over to SPI.

There has got to be a smoother way to do this. Can I get the chip into SPI mode from an exclusively SPI connection? Can I use SPI to turn SPI on? I realize this sounds rather chicken & egg, but I'm not sure what else to do.

Hi, Dear

I'developping a board with ICM20948.
I use the firmware, which is ICM20948_eMD_nucleo_1.0.zip.

I rotated the sensor and mounted it.
So I have to change the orientation of the sensor.

I call following function, inv_device_set_sensor_mounting_matrix(), with matrix of { 0,0,1.f, 0,1.f,0, 1.f,0,0 }
However, the result was not the desired value.

Can anyone tell me How to do?

Hello All,

I am working on a project which requires to detect vibrations in Hz, i am using MPU-9250 sensor and able to read the accelerometer data (3 axis).
Can anyone help to find the vibrations in Hz for the same.

Appreciate your quick revert.

Thanks
Coolhobbyist

I am trying to communicate with the ICM 20789 in the SDK 20789 development board using SPI. I have had a hard time finding proper documentation for this process and am relying on the pin descriptions printed on the board itself: MISO, MOSI, /CS, and SCLK. I have confirmed that I am sending correct messages with an oscilloscope but I get no reply from the MISO pin. I am not even totally sure I am using the correct clock phase, polarity, etc but I have tried every combination. Does anyone have experience using this platform with SPI?

I've been running some tests with the ICM-20689 and it seems like its recording at ~1005Hz with the default SPI sampling frequency, rather than 1000 as stated in the data sheet. I've recorded for short periods of time as well as long periods of time, and there is always more samples than I would expect with a 1k sampling frequency. This effect is most pronounced when the experiment lasts for more than 1000seconds and I end up having more than 5 seconds of extra IMU data. Any thoughts on where things could be breaking down here?