| 摘要 |
PURPOSE:To observe the state of an arbitrary flip flop by permitting a logical unit including a register being the object of scan to select a scan address from a scan control part and to execute a scan operation in the middle of the scan operation. CONSTITUTION:When the scan operation is executed, a scan busty signal 5 becomes '1' and the scan address of a scan address register 2 is inputted to a scan address decoder 7. As the decoding result of the scan address, a scan enable signal 9 becomes '1' and the output of a scan address selector 15 is switched from the output of a scoping scan address register 13 to the scan address which a scan control part 1 outputs, for example. Then, the scan-out operation is executed as against a flip flop group 33 and the content of the flip flop group 33 is set to a scan out data register 3 through a scan out data path 24. Thus, the state of the arbitrary flip flop can be observed even at the time of the scan operation. |
