I have a similar task, but I'm having trouble with data acquisition. I set up the ADXL345 to 3200 Hz, connected to the STM32 using I2C. I want to sample data at a frequency of fs = 256 Hz, so I call the function to retrieve data in an interrupt occurring at that frequency. I send this data to a PC application via UART, which plots graphs for me.
The problem is that I have many repeating samples (about 50 samples are needed to change the value) - unfortunately, I can't afford this because the results and graphs will be incorrect.
Have you encountered such an issue, or could you share the solution you used?