Trying to debug why the magnetic sensor of my MPU9250/6500 won't connect to my Raspberry Pi 4+

I am trying to debug why the magnetic sensor of my MPU9250/6500 won't connect to my Raspberry Pi 4+, but all the other sensors will. I did a bad soldering job on my first one of these sensors and it just wouldn't connect. I got two new ones though and both of them are detected and give the 0x68 address and work except for the magnetic sensor (if I comment out self.configureAK8963(self.mfs, self.mode), I don't get any errors).

So. my question is, is it possible I just have two bad solders that give the same error message or is it a software problem?

I can't see any problems with the physical unit:

Code

import sys
sys.path.append('/home/tor/robot/MPU-9250-Sensors-Data-Collect/MPU-9250-Sensors-Data-Collect/mpu9250_jmdev')
from registers import *
from mpu_9250 import MPU9250
import time
import logging
##################################################
# Create                                         #
##################################################
mpu = MPU9250(
    address_ak=AK8963_ADDRESS, 
    address_mpu_master=MPU9050_ADDRESS_68, # In 0x68 Address
    address_mpu_slave=None, 
    bus=1, 
    gfs=GFS_1000, 
    afs=AFS_8G, 
    mfs=AK8963_BIT_16, 
    mode=AK8963_MODE_C8HZ)
##################################################
# Configure                                      #
##################################################
mpu.configure() # Apply the settings to the registers.
##################################################
# Show Values                                    #
##################################################
while True:
    print("|.....MPU9250 in 0x68 Address.....|")
    print("Accelerometer", mpu.readAccelerometerMaster())
    print("Gyroscope", mpu.readGyroscopeMaster())
    print("Magnetometer", mpu.readMagnetometerMaster())
    print("Temperature", mpu.readTemperatureMaster())
    print("\n")
    time.sleep(1)

Results

Traceback (most recent call last):
  File "/usr/local/lib/python3.8/dist-packages/mpu9250_jmdev/mpu_9250.py", line 97, in configure
    self.configureAK8963(self.mfs, self.mode)
  File "/usr/local/lib/python3.8/dist-packages/mpu9250_jmdev/mpu_9250.py", line 233, in configureAK8963
    self.writeAK(AK8963_CNTL1, 0x00, 0.1)
  File "/usr/local/lib/python3.8/dist-packages/mpu9250_jmdev/mpu_9250.py", line 1013, in writeAK
    self.bus.write_byte_data(self.address_ak, register, value)
  File "/usr/local/lib/python3.8/dist-packages/smbus2/smbus2.py", line 458, in write_byte_data
    ioctl(self.fd, I2C_SMBUS, msg)
OSError: [Errno 121] Remote I/O error

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/lib/python3.8/dist-packages/mpu9250_jmdev/mpu_9250.py", line 97, in configure
    self.configureAK8963(self.mfs, self.mode)
  File "/usr/local/lib/python3.8/dist-packages/mpu9250_jmdev/mpu_9250.py", line 233, in configureAK8963
    self.writeAK(AK8963_CNTL1, 0x00, 0.1)
  File "/usr/local/lib/python3.8/dist-packages/mpu9250_jmdev/mpu_9250.py", line 1013, in writeAK
    self.bus.write_byte_data(self.address_ak, register, value)
  File "/usr/local/lib/python3.8/dist-packages/smbus2/smbus2.py", line 458, in write_byte_data
    ioctl(self.fd, I2C_SMBUS, msg)
OSError: [Errno 121] Remote I/O error

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "sensorTest.py", line 13, in <module>
    mpu.configure() # Apply the settings to the registers.
  File "/usr/local/lib/python3.8/dist-packages/mpu9250_jmdev/mpu_9250.py", line 102, in configure
    self.configure(retry - 1)
  File "/usr/local/lib/python3.8/dist-packages/mpu9250_jmdev/mpu_9250.py", line 102, in configure
    self.configure(retry - 1)
  File "/usr/local/lib/python3.8/dist-packages/mpu9250_jmdev/mpu_9250.py", line 105, in configure
    raise err
  File "/usr/local/lib/python3.8/dist-packages/mpu9250_jmdev/mpu_9250.py", line 97, in configure
    self.configureAK8963(self.mfs, self.mode)
  File "/usr/local/lib/python3.8/dist-packages/mpu9250_jmdev/mpu_9250.py", line 233, in configureAK8963
    self.writeAK(AK8963_CNTL1, 0x00, 0.1)
  File "/usr/local/lib/python3.8/dist-packages/mpu9250_jmdev/mpu_9250.py", line 1013, in writeAK
    self.bus.write_byte_data(self.address_ak, register, value)
  File "/usr/local/lib/python3.8/dist-packages/smbus2/smbus2.py", line 458, in write_byte_data
    ioctl(self.fd, I2C_SMBUS, msg)
OSError: [Errno 121] Remote I/O error

If I put try/except blocks around smbus2.py (ioctl(self.fd, I2C_SMBUS, msg)), I can get data for the other three sensors:

|.....MPU9250 in 0x68 Address.....|
Accelerometer [-1.210205078125, -8.0, -8.0]
Gyroscope [43.9453125, -1.373291015625, -21.270751953125]
[OSError(121, 'Remote I/O error'),
 <smbus2d.SMBus object at 0xffff8d0f20a0>,
 12,
 3,
 7,
 None]
Magnetometer [0.0, 0.0, 0.0]
Temperature 24.258753407014705

What the offending function looks like:

    def read_i2c_block_data(self, i2c_addr, register, length, force=None):
        """
        Read a block of byte data from a given register.

        :param i2c_addr: i2c address
        :type i2c_addr: int
        :param register: Start register
        :type register: int
        :param length: Desired block length
        :type length: int
        :param force:
        :type force: Boolean
        :return: List of bytes
        :rtype: list
        """
        if length > I2C_SMBUS_BLOCK_MAX:
            raise ValueError("Desired block length over %d bytes" % I2C_SMBUS_BLOCK_MAX)
        self._set_address(i2c_addr, force=force)
        msg = i2c_smbus_ioctl_data.create(
            read_write=I2C_SMBUS_READ, command=register, size=I2C_SMBUS_I2C_BLOCK_DATA
        )
        msg.data.contents.byte = length
        try:
            ioctl(self.fd, I2C_SMBUS, msg)
        except Exception as e:
            if hasattr(e, 'message'):
                print(e.message)
            pprint([e, self, i2c_addr, register, length, force])
        return msg.data.contents.block[1:length + 1]

The sensor is readable and is detecting the correct address:

tor@tor:~/robot$ i2cdetect -y 1
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- -- 
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
40: -- -- -- -- -- -- -- -- 48 -- -- -- -- -- -- -- 
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
60: -- -- -- -- -- -- -- -- 68 -- -- -- -- -- -- -- 
70: -- -- -- -- -- -- -- --

Thanks!

jefmenegazzo / mpu-i2c-drivers-python

Trying to debug why the magnetic sensor of my MPU9250/6500 won't connect to my Raspberry Pi 4+ #14