Sampling a BMI160 sensor at 1600hz

[Ranajyoti Chakraborti]

Hi
I am using a nrf52832 board with a BMI160 sensor. I am trying to sample Accel and Gyro at 1600hz using a timer. The timer timeout is set at 20 ticks (32768/1600) @32768 hz (which is the timer resolution of NRF52832. I am not getting anywhere near 1600hz. Is there a better way of doing this?

[Jørgen Holmefjord]

Hi,

• How you are interfacing the device, and what you are doing in the timer handler?
• Are you using SPI or TWI bus?
• What rate are you able to sample the sensor at?

Best regards,
Jørgen

[Jørgen Holmefjord]

How do you measure the sample rate? Sending notifications on BLE at a rate of 1600 Hz might not work, and will heavily depend on your BLE configurations.

Please try removing the part where you send the data over BLE, and toggle a GPIO to measure the rate you are able to read data over SPI. 

[Ranajyoti Chakraborti]

It would be very kind of you if you can elaborate on the BLE configuration you mentioned. One of the things I was planning on trying is to store the data in the program memory or in a flash memory and then transmit from there. But that too seems to be tough as the limit of BLE transmission seems to be 20 bytes and from whatever I could gather from my logging that the Softdevice internal buffer is holding around 400 bytes of data. To answer you question about measurement currently I have a .Net service running on a Windows 10 machine which receives the data and logs them. The BMI160 data includes a tick count of the BMI160 internal clock. The differential of consecutive tick count and the number of data received per second is what I am relying on to calculate the transmission speed.