HowTo: nRF52840 Dongle + 6 Axis IMU connected via SPI -> sending raw data with BLE to MatLab

[Matthias Lauer]

Hi,

I want to connect "nRF52840 Dongle" via SPI to an 6-Axis IMU (Adafruit ICM-20649 / InvenSense). The collected data (cycle = appx. 10ms) should be sent out with BLE to MatLab.

Is the an example or a comperable project on which I can build on?

For example I am not sure if I should use NRF-Connect or Arduino as platform in VS Code. I have tested both and got e.g. Blinky sketch worked.

Also reading data from IMU sensor and print out on serial terminal was ok with arduino.

Thank you in advance.

[Simon]

I'm not aware of any samples with both Bluetooth and SPI/ICM-20649 support, but if you get both of them to work separately, it should be easy to merge them together.

Unfortunately, I could not find any ICM-20649 related samples. However I found a sample for the icm42605 (not sure how different it is from the icm20649?): ncs/zephyr/samples/sensor/icm42605. Maybe you could make it work by modifying the underlying driver ncs/zephyr/drivers/sensor/icm42605.

If you can't get that to work, you can use the SPI API directly and write the driver for ICM20649 yourself on top of that, check out these SPI samples:

• https://github.com/crfosse/ncs_projects/tree/main/peripheral_zephyr/spi
  • You might need to modify this a little to make it compatible with NCS v1.8.0
• https://github.com/nrfconnect/sdk-zephyr/tree/d4cde89906b0738436bb566f75b6fbbf57ff741f/tests/drivers/spi/spi_loopback 
  • A test demonstrating how to use the SPI API

Check out these folders to find Bluetooth samples:

ncs/nrf/samples/bluetooth

ncs/zephyr/samples/bluetooth

Maybe https://github.com/nrfconnect/sdk-nrf/tree/v1.8.0/samples/bluetooth/peripheral_uart would be a good starting point?

Best regards,

Simon