NHS3100SENSORDB Accelerometer Raw Data Extraction

[vulpliks]

Hello, recently I acquired a new NHS3100 SensorBoard for testing its functionality.

I installed the Android App SensorBoard Monitor on my cellphone, connected to the board and it seems ok, I can log the Temperature, Humidity, and sense some Tilting information.

However, this is not exactly what I expect. I would like to measure the output of the accelerometer for measuring pitch and roll angles. Is there a way that I can communicate with the board using JTAG (LPC-Link 2), read these values on Windows 10 and log the accelerometer information just like the Temperature and Humidity?

I have installed the LPCXpresso software on my computer, but do not have any clue of how to communicate with the board.

Thank you very much

[stevekuh]

Could you let me know if we could have the source code of the phone App? I would like to modify it for our use with the NHS3100SENSOR board.

[driesmoors]

The source code for the apps is available in the SDK under sw/XF/Monitor

[driesmoors · Accepted solution]

Hi,

In the SensorBoard Monitor demo, the FXLS accelerometer is configured to report threshold excursions, and based on that, different events are deduced. The firmware application running on the NHS3100 does not interpret the raw XYZ data. This is done on purpose to save battery life, as it allows the NHS3100 IC to spend more time in deep power down mode.

It is definitely possible to work with the raw accelerometer data, and 'live stream' them to your PC.

• The least disturbing way to communicate to your PC is to use a UART connection. On the IC, use the uarttx module; on the PC side, use an FTDI FT232R.
• The driver of the FXLS IC on the NHS3100 is not a full implementation of all the functionality of the accelerometer; you must expand it and change the configuration settings. Set a watermark level, and when the interrupt is fired when the accelerometer's internal buffer is nearly full, fetch all the raw data. Then pass it upwards, so that the application can work it it and send it off over UART to your PC.

Some pointers:

• To get started with development of the Sensor Board using the LPCXpresso IDE, check out UM10876 under <SDK>/docs
• To learn how to use the uarttx module, check the firmware documentation in the code, but also under <SDK>/docs/firmware.html > Modules > Modules > uarttx: Uart Tx-only module.
• The FXLS datasheet can be found here: https://www.nxp.com/docs/en/data-sheet/FXLS8974CF.pdf

Kind regards,
Dries.