Methods of motion processing and related devices are provided. A representative method includes: generating a plurality of first sensor samples; generating a plurality of second sensor samples at a sampling rate according a first clock signal; storing the second sensor samples in a first buffer; fetching the first sensor samples; fetching the second sensor samples in batches from the first buffer; merging the first sensor samples and the second sensor samples to form a sensing merged signal; storing the sensing merged signal in a second buffer; providing a first preset processing signal; and selectively performing a second preset processing according to the first preset processing signal.