Abstract: A method for determining an ending of a frame in serial data is provided. The frame has in sequence a header, a data stream, and a cyclic redundancy check (CRC) corresponding to the data stream. The last bit of the frame is the last bit of the CRC. The method includes (a) detecting the header of the frame, (b) determining the initial bit of the data stream according to the header of the frame, (c) utilizing a generator polynomial corresponding to the CRC of the data stream to perform CRC calculation on the initial bit of the data stream, in order to generate a remainder, and (d) comparing the remainder with a fixed value, wherein the last bit of the plurality of bits is determined to be the ending of the frame when the remainder equals to the fixed value.