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    BNO055 power on reset issues

    BNO055 power on reset issues

    New Poster

    I'm trying to resolve a persistent issue I'm having with a BNO055 IMU on a custom PCBA. I'm communicating via I2C and am experiencing different behavior between device reset (using "Power on Reset" reset pin) with and without power cycling. In situations where I reprogram my MCU and start directly into my application code without power cycling, the IMU will respond with NAKs to any and all read/write messages. If I power-cycle the system, it works correctly. In both scenarios I'm pulling the reset pin low for ~25ms, pulling the reset pin high, and then waiting for ~725ms before initiating I2C communication. All other signals (COM1, COM2, PS0, PS1, nBOOT_LOAD_PIN) are connected to VDD or GND directly or through a 10kΩ resistor. A partial schematic is attached.

    The firmware is heavily based upon the BNO055 XPlained Pro example code and is being run on a SAMD21G18A.

    Can you help me to understand the differences in behavior between device reset for the BNO055 from an 'unknown' state and from a power-on state? Do I need to set the SDA/SCL lines to a certain level before/during/after Power on Reset?

    Attached are logic analyzer screenshots of the system failing without power cycle (BNO055_noPowerCycle.png) and working with power cycle (BNO055_withPowerCycle.png), as well as a partial schematic (BNO055_sch.png).

    17 REPLIES 17


    I exactly did the same thing. Please find the attached schematics. Even the current consumption in suspend mode is 180 uA. The Bosch flyer board gives 3.3uA with same code. In low power mode, my board gives 500uA and flyer board gives 145uA. Also is performance affected if I supply 2.5volt instead of 3.v volt rail?



    Rohit Soni


    Performance is not affected by voltage. At 2.5 volts, the sensor would operate at maximum performance.

    The current consumption does not include the crystal, i2c communication, or the current flowing through R39 due to internal pull-up on COM3 pin. (see Table 4-6)

    Can you confirm current measurement and config ?


    Hi, Bosh!! Please tell me if the FW has already been released to fix this issue? Any hot news about?