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 Computation Operation for a more detailed description of the mathematical operation). In this mode,
the ADCRS bits determine the cut-off frequency of the low-pass filter (as demonstrated by Digital Filter/Average).