BMI08x Synced Frequency

[harry7]

Hi,

We are using the BMI085 in synced mode with the output rate set to 2KHz. The actual output rate seems to be more like 1980Hz. Is this within the expected range or is there a possibility that we are using the device wrong? What is the expected tolerance on the data rate in synced mode?

Thanks!

[o_o · Accepted solution]

Hi Harry,

With BMI085, the gyroscope is always sampling at its own rate. In synced mode, the gyroscope is the master of the clock, and the accelerometer is synchronized to the gyroscope. Therefore the data rate accuracy is governed by the gyroscope data rate accuracy.

1% error is possible and would not be considered a failure part, but quite rare. How many devices have you built and what is the data rate distribution plot ?

Which measuring equipment did you use to measure this 1980Hz ?

o_o

[harry7]

Hi o_o,

Thanks for the detailed reply. We measured the rate directly on the device consuming the IMU data. After further investigation we narrowed the problem down to occasionally missed interrupts on the host device. Without missed interrupts the rate is closer to 2000Hz (+- 3Hz).

Thanks,

Harry