BNO055 Long I2C clock stretching

[Digisolve]

I find that the BNO055 induces quite long I2C clock stretching. The BNO055 is running in normal power mode and DNOF mode. Below is the CALIB STATUS read once every 1.2 seconds. There is no other I2C traffic.

Below are some scope traces; These were all taken during the same test. It randomly occurs

Is this expected behaviour, or do I have an problem?

[Digisolve]

I'm having inacurate heading readings. I just want to be sure that everything is operating ok. There's no mention in the data sheet about potential clock stretching induced by the BNO055, so I need to be sure that I've not set anthing up wrong, or running the I2C bus too fast

[Digisolve]

In my waveform you can see I'm only reading one register 0x35 (CALIB_STAT) & it's during this one-byte read I'm seeing clock stretching occuring. I suspect this is ok, but I need to know if this is expected. If not, then I need some guidance as to how to address this.

I also this this occuring on an independent system with a Aduino board fixed with the BNO055

[BSTRobin]

Hi Digisolve,

If there is no protocol error in your waveform, such as lack of stop, no response, etc., then this is a normal communication.

[Digisolve]

Thank you. It works fine so I must assume it woks correctly.

[BSTRobin]

Welcome, Digisolve.