| 摘要 |
PURPOSE:To extract and inspect parallel data as serial data by designation from an outside from a regular operation terminal of an LSI by selecting the parallel data given by plural register outputs and converting them to the serial data, and outputting them. CONSTITUTION:An address is inputted from an external terminal of an LSI in accordance with a regular operation and an insulating operation, and by its address designation, a decoding port 111 outputs selecting signals 108 (so... sn). Each switching circuit 103 inputs the signal 108 and switches the input. For instance, by inputting the selecting signal so, parallel data i1o... imo are inputted to a converting circuit 104. These (m) pieces of data are extracted from a terminal 109 as serial data 203 by the circuit 104. Also, the data i1o... imo, and other data can be used as an original operation output of the LSI, and inspection data, respectively, and by designating an address, the regular operation and the inspection can be switched and outputted. That is, the state of (m) pieces of an output terminal of a register which cannot be inspected directly from the outside of the LSI is switched and they are inputted to the circuit 104, and can be extracted as serial data 203 from the terminal 109. |
