PURPOSE: To surely save internal state data to external memory when power interruption occurs by restoring data saved via a scan pass to an original register.

CONSTITUTION: A counter 4 counts a scan clock SC, and outputs the address A of the external memory 3 in which the data outputted from an integrated circuit 2 is stored. The integrated circuit 2 outputs the internal state data from a scan output terminal SO synchronizing with the scan clock SC, and such data is supplied to the data input terminal D1 of the external memory 3, and is stored in an address-designated position by the counter 4. In other words, the internal state data transferred synchronizing with the scan clock SC by utilizing the scan pass of the integrated circuit 2 can be outputted from the scan output terminal SO and it can be saved to the external memory 3. Thence, when the power source of a system is restored. the data restoration mode of resume function is set, and the system restores saved internal state data to the integrated circuit 2.