Patent ID: 7280544

Claim:
A transmission convergence sublayer circuit of an asynchronous transfer receiver for receiving data cells submitted from a deframer after receiving a data stream enable signal from the deframer, wherein the data cell comprises a plurality of bytes divided into a header and a payload, the transmission convergence sublayer circuit comprising: a byte-wise data pipeline for receiving and temporarily holding the data bytes in the data cell; a header cyclic redundancy checker for receiving the data bytes and transmitting a syndrome code capable of indicating the presence a header cell; an idle cell identifier for deciding whether the data cell received by the byte-wise data pipeline is a non-idle data cell or not; a cell delineation state machine for determining a transmission state of the data cell according to a content and frequency of the syndrome code and transmitting state signals reflecting a current state, wherein possible states at least include a search state and a complete synchronization state; a byte pointer for issuing a pointer signal, wherein the pointer signal indicates a sequence number of the byte belonging to the data cell received by the byte-wise data pipeline and serves as an address pointer for sending double word data converted from newly received bytes into a buffer; a descrambler for descrambling a plurality of bytes residing temporarily in the byte-wise data pipeline and sending resulting descrambled data to the buffer; and a write-in buffer controller for writing the descrambled data into the buffer according to the indication provided by the byte pointer when permission to do so is granted by the idle cell identifier and the cell delineation state machine, wherein the transmission convergence circuit further includes a cell counter for responding to conditions reguiring the cell delineation state machine to change from a search state into a complete synchronization state and vice versa according to the pointer signal submitted by the byte pointer, and the cell counter acts by first counting number of received data cells after the state transition and deciding if going into the complete synchronization state or returning to the search state is necessary.