Hi all,
I set the FIFO watermark level to 15, and ODR at 3200Hz, which makes a sample every 312.5us.The INT0 is the watermark interrupt pin.
As you can see we take 346us to:
which is more than 312.5us.
My question is : Do we lose a sample ?
Hello patopat thanks for your patience.
After checking the configuration I am not sure if I am following your scope or there is a little misunderstanding;
-You are working on "Stream mode" (Pg-11 ADXL375 DS) but you are checking the status register. (0x39) This register and the bit D7 within it (FIFO_TRIG) are only related with the "Trigger Mode" (Pg-12 DS). Since you are working with the Stream mode, you should ignore the register 0x39.
-If I am not mistaken, you are asking about a system limitation in which you can only read data (15 samples) every 346 us, this should not limit the application at first sight, because if you are able to process the whole batch of 15 samples within those 346 us, you have plenty of sampling time space available, until the 17 following 312 us samples fill the FIFO (32 samples space) and you start to lose information.
In any case if you are worried about loosing data you should check the register 0x30 INT_SOURCE bit D0 Overrun (Pg-23 DS). With your current configuration you are only getting an interruption when you reach the 15 samples watermark limit, which should be enough to avoid data lost if your system retrieves the FIFO info within the times specified above.
I may also recommend you to follow Pg-23 DS recommendation of configure reg 0x2F before 0x2E.
Let me know if this solves your problem, and have a nice day
Mario SM
