Patent ID: 6526534
Filing Date: 2003-02-25
Classification: G01R

Abstract:
A communication element comprising:a plurality of input-side boundary cells; a plurality of output-side boundary cells corresponding to said input-side boundary cells; and a TAP circuit for controlling input and output of data to/from said input-side and output-side boundary cells, said TAP circuit being connected to a TCK line to which a clock signal is inputted, a TMS line to which a mode signal for switching operation modes is inputted, and data input and output lines for inputting and outputting the data to/from a terminal equipment which is an object of communication, wherein said input-side boundary cells are connected in parallel to said corresponding output-side boundary cells through said TAP circuit; said TAP circuit has at least (a) a function of transferring data stored in said input-side boundary cells to said output-side boundary cells; (b) a function of generating data, number of bits thereof being controlled for controlling the terminal equipment or for other purposes in accordance with the data stored in the input-side boundary cells and then this data being outputted from terminal-equipment-side output terminal; said TAP circuit executes an operation mode corresponding to said functions (a) or (b) due to an operation mode signal inputted to said TAP circuit; said input-side boundary cells store the data to be processed in the operation mode of said TAP circuit; and said output-side boundary cells store data having been processed in the operation mode of said TAP circuit.