Hello,
I made some measurements on my APM board togethet with a 3DR power module and an atto 90A board.
Both sensors gives a stable sense voltage to the APM board but the reading out on MP is allways oscillating between 16.5 and 16.7V (multimeter is reading a perfect 16.6V). So I checked the shematics of the APM board and saw that the analog reference voltage supply pin (AVCC) was directly connected to VCC ! When I check the recommendations of Atmel about AVCC they ask to use an LPF between VCC and AVCC (just a 10mH inductance with a 100nF capacitor). You can imagine now my question, Why is this LPF not implemented ? My two cents are that if the reference voltage is not stable then the ADC’s can’t do their job’s on an accurate manner. What do you think about this ?
Regards,
Bernard