CELL DEVICE FOR CHANNELS OF ADAPTIVE LAYER-2 IN ASYNCHRONOUS TRANSFER MODE

摘要

PURPOSE: A cell device for channels of adaptive layer-2 in an asynchronous transfer mode(ATM), is provided to utilize an utopia level in 1 or 2 with four 53 multiplied by 8-bit dual port RAM of an input terminal and a 53 multiplied by 8-bit FIFO of an output terminal so as to interface with a chip built-in an utopia function. CONSTITUTION: An input selecting circuit(1) selectively stores inputted data in one among four input buffers. First-fourth ATM adaptive layer(AAL)2 input buffers(2-5) are connected to an output terminal of the input selecting circuit. A read controlling circuit(6) controls a reading operation according to an AAL2 packet format. AAL2 cell header/cells per second(CPS) packet processing circuits(7,8) convert an ATM header by connecting to the read controlling circuit. A padding processing circuit(9) divides an AAL2 packet into users by padding an output of the CPS packet processing circuit. A write controlling circuit(10) stores the divided data in one output buffer. First-fourth AAL2 output buffers(11-14) store data by connecting to an output terminal of the write controlling circuit. An output selecting circuit(15) selects to data from the output buffers(11-14).