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

[Ranajyoti Chakraborti]

Hi

The sensor is attached to SPI4 interface. The timer handler simply uses the BMI160 SDK code to read from the sensor using nrf_drv_spi_transfer and then transfer data to BLE sofdevice buffer using sd_ble_gatts_hvx. I am able to sample max upto 200 hz. No matter how low the tick count I set for the timer. The timer gets started by app_timer_start

[awneil]

Are you confusing the Sensor's internal sample rate with the rate at which you read data over its external interface ... ?

[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]

This is actually a requirement I am trying to meet to read the sensor 1600 times / sec, so essentially collect 1600 readings / sec and transmit that over BLE. I am not certain that this can be achieved and that is why I posted the question.