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    BNO055 - Custom PCB shows all values as zeros.

    Prajwal_shenoy
    New Poster

    BNO055 - Custom PCB shows all values as zeros.

    We made a custom PCB using BNO055 and all other components as mentioned in the datasheet. Unfortunately, all values are read as zeros.  I am using  arduino IDE. Upon checking the system status, I get the following error:

    System Status: 0x5
    Self Test: 0x8
    System Error: 0x2

    Which according to the datasheet is:

    5 = Sensor fusio algorithm running
    8= MCU self test pass. Accelerometer, gyro, magnetometer self test failed.

    2= System initialization error

    Can someone please help me in understanding what could have gone wrong?

     

    Thank you

    4 REPLIES 4
    BSTRobin
    Community Moderator

    Re: BNO055 - Custom PCB shows all values as zeros.

    Hello Prajwal_shenoy,

    Could we know detailed information about your hardware and software?

    Prajwal_shenoy
    New Poster

    Re: BNO055 - Custom PCB shows all values as zeros.

    Hi

    Please find the attached hardware details. The code I used was from arduino example under the Adafruit BNO055 library. The code is also attached.


    Thank you

    Prajwal_shenoy
    New Poster

    Re: BNO055 - Custom PCB shows all values as zeros.

    I cross-checked my connections with the 12C connection diagram in the datasheet (page 97, Section 5.2). It looks like I have made a few mistakes which I am going to highlight below: 

    1. Pin 15 and 16, I have left open whereas the datasheet 12C connection diagram has them connected to the ground. (Note: in another version of my prototype, I had left these pins unconnected and it had worked. Is it necessary to connect these pins to the ground?)
    2. Pin 3, I have not connected to Vdd but in the datasheet, it is connected to Vdd. (Note: I feel this might be the problem because the only difference (as far as the connections to the BNO0555 are concerned)between my previous prototype (which worked) and the current prototype connections is this.)
    3. Pin 9 should be connected to a 100nF capacitor as per the datasheet connections, I have used 1 micro Farad instead.
    4. Between Pins 28 and 25, capacitors 120nF and 6.8 nF are connected in parallel as per the datasheet. I have used only 120nF for my current prototype.

    Could you kindly let me know which of the above mistakes I should have absolutely avoided? Any further suggestions or insights that will help me would also be great.

    Additionally, the temperature used during soldering was 240 degrees. I hope this is fine. 

    Thank you for the support.  

     

    BSTRobin
    Community Moderator

    Re: BNO055 - Custom PCB shows all values as zeros.

    Hello Prajwal_shenoy,

    Your schematic had mistake connection, please restrictly check it with reference diagram in data sheet.

    BNO055 I2C connection.png

    This is soldering guideling.

    BNO055 soldering guideling.png

     

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