33.5.6 Low-pass Filter Mode

The Low-pass Filter mode (ADMD = 100) acts similarly to the Average mode in how it handles samples (accumulates samples until ADCNT value greater than or equal to ADRPT, then triggers threshold comparison), but instead of a simple average, it performs a low-pass filter operation on all of the samples, reducing the effect of high-frequency noise on the average, then performs a threshold comparison on the results. (see 33.5 Computation Operation for a more detailed description of the mathematical operation). In this mode, the ADCRS bits determine the cutoff frequency of the low-pass filter (as demonstrated by 33.5.1 Digital Filter/Average).